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https://math.stackexchange.com/questions/464565/definition-of-the-integral-in-non-standard-calculus
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# Definition of the integral in non-standard calculus
In the sources I've seen, the integral is defined in non-standard calculus as the hyperreal extension of a function related to Riemann sums. E.g.,
Let $$S(\Delta x) = \sum_{a}^{b}f(x)\Delta x$$ be a function of a Riemann sum where $\Delta x$ is the length of each partition. Then let $S^*(\Delta x)$ be the hyperreal extension of that function, which exists due to the transfer principle. Then we can talk about $S^*(\rm dx)$, where $\rm dx$ is an infinitesimal.
This is very simple and seems to work, but it doesn't really explain what's happening in the function $S^*(\Delta x)$. What does a Riemann sum with infinitesimal partitions mean? How do I sum $H$ terms, where $H$ is a hyperinteger?
Can anyone direct me to other definitions of integrals in non-standard calculus (not necessarily Riemann equivalent) that answer some of these questions? Or possibly a textbook that goes into more detail about this subject?
Edit: Let me clarify something. I understand the definition. I certainly don't think it's not well-defined.
I just feel it sort of "covers up" the really interesting bits. "Interesting bits" includes, for example, using induction on the hyperintegers.
• What is covered up is the construction of the hyperreals. If you don't understand it, you can't claim to understand them intuitively without it being just blind faith. And remember that the hyperreals are simply the ultraproduct of the reals using an ultrafilter on the naturals. So if you think the usual reals don't make intuitive sense, then you can forget about the hyperreals making sense. I upvoted your question but I do think you chose the wrong answer, since it covers up what is covered up. – user21820 Sep 11 '17 at 8:00
• Remember that you can't just willy-nilly integrate any function; it must be first-order definable so that the transfer principle works. See for example this post and the chain of comments, for just the surface of the iceberg that has been covered up. – user21820 Sep 11 '17 at 8:04
## 2 Answers
The integral is not the hyperfinite sum $S^{\ast}(dx)$ but rather the standard part of that hyperfinite sum. This is similar to the situation with the derivative, where one can form the quotient of infinitesimals $\frac{dy}{dx}$ where $dy$ is the $y$-increment corresponding to the $x$-increment $dx$. Here the derivative is not the quotient but rather the standard part of that quotient. Usually one denotes the infinitesimal $x$-increment by the symbol $\Delta x$ and the corresponding $y$-increment by $\Delta y$. The derivative is then defined to be $$\text{st}\left(\frac{\Delta y}{\Delta x}\right)$$ rather than the ratio itself. Here "st" is the standard part function. Then one sets $dx=\Delta x$ and defines $dy$ by $dy=f'(x)dx$ so that the derivative can be written as $dy/dx$.
I have had good experience teaching using Keisler's textbook which is available online here. A more advanced companion volume by Keisler that covers more of the theoretical material can be found here.
To answer more specifically your questions "What does a Riemann sum with infinitesimal partitions mean? How do I sum H terms, where H is a hyperinteger?": your intuition of a very small partition step and a very large number of partition points is already the right intuition. The notion of an infinite hyperinteger is merely a way of formalizing your intuition. The advantage of the hyperreal approach is that such intuitions, which remain at the level of vague musings in the epsilon, delta approach (without infinitesimals), can now be formalized rigorously. This allows one to write down proofs that are closer to the original intuition than in the epsilon, delta approach. One notion that gets clarified this way is that of a Cauchy sequence; see the related discussion I would like to know an intuitive way to understand a Cauchy sequence and the Cauchy criterion.
• Thank you! I was familiar with Keisler's textbook, but not familiar with the additional volume. Do you know any other material on the subject of non-standard analysis/calculus, at around the same level? – GregRos Aug 11 '13 at 16:30
• A slightly more advanced text is Goldblatt, Robert, Lectures on the hyperreals. An introduction to nonstandard analysis. Graduate Texts in Mathematics, 188. Springer-Verlag, New York, 1998. I enjoyed teaching from that, also. For a discussion of the basic intuitions, you could consult the question math.stackexchange.com/questions/405492/… – Mikhail Katz Aug 11 '13 at 16:36
Due to the transfer principle, as long as you don't compare them against each other, nonstandard analysis is completely indistinguishable from standard analysis.
In standard analysis, you have the (standard) finite summation operator: given (standard) integer limits $a \leq b$ and a (standard) real-valued function $f$ of the integers, the operator produces a real number $S$, which we often write as
$$S = \sum_{n=a}^b f(n)$$
If we apply transfer, we get the (nonstandard) hyperfinite summation operator: given hyperinteger limits $a \leq b$ and an internal hyperreal-valued function $f$ of the hyperintegers, the operator produces a hyperreal number $S$. We might write it as
$$S = {}^\star\sum_{n=a}^b f(n)$$
to emphasize that this is the nonstandard summation operator rather than the standard summation, but I would prefer to just write it as
$$S = \sum_{n=a}^b f(n)$$
If you were so inclined, you don't even have to bother with the transfer principle. The nonstandard integers satisfy the (internal) principle of induction, so you could just recursively define the nonstandard summation operator in any usual way, such as
$${}^\star\sum_{n=a}^a f(n) = f(a)$$ $${}^\star\sum_{n=a}^{b+1} f(n) = f(b+1) + {}^\star\sum_{n=a}^b f(n)$$
which recursively defines the summation for all hyperintegers $a,b$ with $a \leq b$, and for all (internal) hyperreal-valued functions $f$ of the hyperintegers.
The reason you are having trouble seeing that the summation is well-defined is because you are implicitly trying to use induction over standard integers to justify recursions over nonstandard integers, but that simply doesn't work.
• if the OP understood the notion of "internal" (as in "internal induction" and "internal hyperreal-valued functions"), he wouldn't have phrased the question the way he did. Also, understanding what you mean when you write "nonstandard analysis is completely indistinguishable from standard analysis", one needs a fairly detailed grasp of the semantic/syntactic distinction in logic, as well as the notion of first-order sentence and such. I certainly hope he benefits from your answer, but it may be helpful to provide some motivating details, as well. – Mikhail Katz Aug 11 '13 at 14:02
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2019-06-17 05:03:41
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https://www.transtutors.com/questions/if-an-object-is-located-at-0-5-times-the-focal-length-of-a-thin-lens-calculate-the-l-3608846.htm
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# If an object is located at 0.5 times the focal length of a thin lens, calculate the location and... 1 answer below »
If an object is located at 0.5 times the focal length of a thin lens, calculate the location and lateral magnification of the image. Assume that both sides of the lensare filled with air, that the index of refraction of the lens is n=1.5, and that the radius of curvature of the surface is R=15 cm
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2019-09-16 14:12:49
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https://en.cppreference.com/w/cpp/preprocessor/replace
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Replacing text macros
C++
Compiler support Freestanding and hosted Language Standard library headers Named requirements Feature test macros (C++20) Language support library Concepts library (C++20) Diagnostics library General utilities library Strings library Containers library Iterators library Ranges library (C++20) Algorithms library Numerics library Localizations library Input/output library Filesystem library (C++17) Regular expressions library (C++11) Atomic operations library (C++11) Thread support library (C++11) Technical specifications Symbols index External libraries
C++ language
General topics
Flow control
Conditional execution statements
Iteration statements (loops)
for range-for (C++11)
Jump statements
goto - return
Functions
Function declaration
Lambda function declaration
inline specifier
Dynamic exception specifications (until C++20)
noexcept specifier (C++11)
Exceptions
Namespaces
Types
Specifiers
decltype (C++11) auto (C++11) alignas (C++11)
Storage duration specifiers
Initialization
Expressions
Alternative representations
Literals
Boolean - Integer - Floating-point
Character - String - nullptr (C++11)
User-defined (C++11)
Utilities
Attributes (C++11)
Types
typedef declaration
Type alias declaration (C++11)
Casts
Implicit conversions - Explicit conversions
static_cast - dynamic_cast
const_cast - reinterpret_cast
Memory allocation
Classes
Class-specific function properties
Virtual function override specifier (C++11) final specifier (C++11)
explicit (C++11) static
Special member functions
Default constructor Copy constructor Move constructor (C++11)
Copy assignment Move assignment (C++11) Destructor
Templates
Template specialization Parameter packs (C++11)
Miscellaneous
Preprocessor
#if#ifdef#ifndef#else#elif#endif #define#undef#,## operators #include__has_include(C++17) #error #pragma_Pragma(C++11) #line
The preprocessor supports text macro replacement. Function-like text macro replacement is also supported.
Contents
Syntax
#define identifier replacement-list(optional) (1) #define identifier( parameters ) replacement-list(optional) (2) #define identifier( parameters, ... ) replacement-list(optional) (3) (since C++11) #define identifier( ... ) replacement-list(optional) (4) (since C++11) #undef identifier (5)
Explanation
#define directives
The #define directives define the identifier as macro, that is instruct the compiler to replace all successive occurrences of identifier with replacement-list, which can be optionally additionally processed. If the identifier is already defined as any type of macro, the program is ill-formed unless the definitions are identical.
Object-like macros
Object-like macros replace every occurrence of defined identifier with replacement-list. Version (1) of the #define directive behaves exactly like that.
Function-like macros
Function-like macros replace each occurrence of defined identifier with replacement-list, additionally taking a number of arguments, which then replace corresponding occurrences of any of the parameters in the replacement-list.
The syntax of a function-like macro invocation is similar to the syntax of a function call: each instance of the macro name followed by a ( as the next preprocessing token introduces the sequence of tokens that is replaced by the replacement-list. The sequence is terminated by the matching ) token, skipping intervening matched pairs of left and right parentheses.
For version (2), the number of arguments must be the same as the number of parameters in macro definition. For versions (3,4), the number of arguments must not be less than the number of parameters (not (since C++20) counting ...). Otherwise the program is ill-formed. If the identifier is not in functional-notation, i.e. does not have parentheses after itself, it is not replaced at all.
Version (2) of the #define directive defines a simple function-like macro.
Version (3) of the #define directive defines a function-like macro with variable number of arguments. The additional arguments (called variable arguments) can be accessed using __VA_ARGS__ identifier, which is then replaced with arguments, supplied with the identifier to be replaced.
Version (4) of the #define directive defines a function-like macro with variable number of arguments, but no regular arguments. The arguments (called variable arguments) can be accessed only with __VA_ARGS__ identifier, which is then replaced with arguments, supplied with identifier to be replaced.
For versions (3,4), replacement-list may contain the token sequence __VA_OPT__ ( content ), which is replaced by content if __VA_ARGS__ is non-empty, and expands to nothing otherwise. #define F(...) f(0 __VA_OPT__(,) __VA_ARGS__) F(a, b, c) // replaced by f(0, a, b, c) F() // replaced by f(0) #define G(X, ...) f(0, X __VA_OPT__(,) __VA_ARGS__) G(a, b, c) // replaced by f(0, a, b, c) G(a, ) // replaced by f(0, a) G(a) // replaced by f(0, a) #define SDEF(sname, ...) S sname __VA_OPT__(= { __VA_ARGS__ }) SDEF(foo); // replaced by S foo; SDEF(bar, 1, 2); // replaced by S bar = { 1, 2 }; (since C++20)
Note: if an argument of a function-like macro includes commas that are not protected by matched pairs of left and right parentheses (most commonly found in template argument lists, as in assert(std::is_same_v<int, int>); or BOOST_FOREACH(std::pair<int,int> p, m)), the comma is interpreted as macro argument separator, causing a compilation failure due to argument count mismatch.
Reserved macro names
A translation unit that includes a standard library header may not #define or #undef names declared in any standard library header.
A translation unit that uses any part of the standard library may not #define or #undef names lexically identical to:
(since C++11)
except that likely and unlikely may be defined as function-like macros. (since C++20)
Otherwise, the behavior is undefined.
# and ## operators
In function-like macros, a # operator before an identifier in the replacement-list runs the identifier through parameter replacement and encloses the result in quotes, effectively creating a string literal. In addition, the preprocessor adds backslashes to escape the quotes surrounding embedded string literals, if any, and doubles the backslashes within the string as necessary. All leading and trailing whitespace is removed, and any sequence of whitespace in the middle of the text (but not inside embedded string literals) is collapsed to a single space. This operation is called "stringification". If the result of stringification is not a valid string literal, the behavior is undefined.
When # appears before __VA_ARGS__, the entire expanded __VA_ARGS__ is enclosed in quotes: #define showlist(...) puts(#__VA_ARGS__) showlist(); // expands to puts("") showlist(1, "x", int); // expands to puts("1, \"x\", int") (since C++11)
A ## operator between any two successive identifiers in the replacement-list runs parameter replacement on the two identifiers (which are not macro-expanded first) and then concatenates the result. This operation is called "concatenation" or "token pasting". Only tokens that form a valid token together may be pasted: identifiers that form a longer identifier, digits that form a number, or operators + and = that form a +=. A comment cannot be created by pasting / and * because comments are removed from text before macro substitution is considered. If the result begins with a sequence matching the syntax of universal character name, the behavior is undefined. This determination does not consider the replacement of universal character names in translation phase 3. (since C++23) If the result of concatenation is not a valid token, the behavior is undefined.
Note: some compilers offer an extension that allows ## to appear after a comma and before __VA_ARGS__, in which case the ## does nothing when the variable arguments are present, but removes the comma when the variable arguments are not present: this makes it possible to define macros such as fprintf (stderr, format, ##__VA_ARGS__)
#undef directive
The #undef directive undefines the identifier, that is cancels previous definition of the identifier by #define directive. If the identifier does not have associated macro, the directive is ignored.
Predefined macros
The following macro names are predefined in every translation unit.
__cplusplus denotes the version of C++ standard that is being used, expands to value 199711L(until C++11), 201103L(C++11), 201402L(C++14), 201703L(C++17), or 202002L(C++20) (macro constant) __STDC_HOSTED__(C++11) expands to the integer constant 1 if the implementation is hosted (runs under an OS), 0 if freestanding (runs without an OS) (macro constant) __FILE__ expands to the name of the current file, as a character string literal, can be changed by the #line directive (macro constant) __LINE__ expands to the source file line number, an integer constant, can be changed by the #line directive (macro constant) __DATE__ expands to the date of translation, a character string literal of the form "Mmm dd yyyy". The first character of "dd" is a space if the day of the month is less than 10. The name of the month is as if generated by (macro constant) __TIME__ expands to the time of translation, a character string literal of the form "hh:mm:ss" (macro constant) __STDCPP_DEFAULT_NEW_ALIGNMENT__(C++17) expands to an std::size_t literal whose value is the alignment guaranteed by a call to alignment-unaware operator new (larger alignments will be passed to alignment-aware overload, such as (macro constant)
The following additional macro names may be predefined by the implementations.
__STDC__ implementation-defined value, if present, typically used to indicate C conformance (macro constant) __STDC_VERSION__(C++11) implementation-defined value, if present (macro constant) __STDC_ISO_10646__(C++11) expands to an integer constant of the form yyyymmL, if wchar_t uses Unicode, the date indicates the latest revision of Unicode supported (macro constant) __STDC_MB_MIGHT_NEQ_WC__(C++11) expands to 1 if 'x' == L'x' might be false for a member of the basic character set, such as on EBCDIC-based systems that use Unicode for wchar_t (macro constant) __STDCPP_THREADS__(C++11) expands to 1 if the program can have more than one thread of execution (macro constant)
__STDCPP_STRICT_POINTER_SAFETY__(C++11)(removed in C++23) expands to 1 if the implementation has strict std::pointer_safety (macro constant)
The values of these macros (except for __FILE__ and __LINE__) remain constant throughout the translation unit. Attempts to redefine or undefine these macros result in undefined behavior.
Note: in the scope of every function body, there is a special function-local predefined variable named __func__, defined as a static character array holding the name of the function in implementation-defined format. It is not a preprocessor macro, but it is used together with __FILE__ and __LINE__, e.g. by assert. (since C++11)
Language feature-testing macros
The standard defines a set of preprocessor macros corresponding to C++ language features introduced in C++11 or later. They are intended as a simple and portable way to detect the presence of said features.
See Feature testing for details.
(since C++20)
Example
#include <iostream>
// Make function factory and use it
#define FUNCTION(name, a) int fun_##name() { return a;}
FUNCTION(abcd, 12)
FUNCTION(fff, 2)
FUNCTION(qqq, 23)
#undef FUNCTION
#define FUNCTION 34
#define OUTPUT(a) std::cout << "output: " #a << '\n'
// Using a macro in the definition of a later macro
#define WORD "Hello "
#define OUTER(...) WORD #__VA_ARGS__
int main()
{
std::cout << "abcd: " << fun_abcd() << '\n';
std::cout << "fff: " << fun_fff() << '\n';
std::cout << "qqq: " << fun_qqq() << '\n';
std::cout << FUNCTION << '\n';
OUTPUT(million); //note the lack of quotes
std::cout << OUTER(World) << '\n';
std::cout << OUTER(WORD World) << '\n';
}
Output:
abcd: 12
fff: 2
qqq: 23
34
output: million
Hello World
Hello WORD World
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2021-12-06 14:20:25
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https://mailman.ntg.nl/pipermail/ntg-context/2016/086398.html
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Ursula Hermann ursula.hermann at univie.ac.at
Fri Aug 5 16:28:43 CEST 2016
```Hello Henry and Alan and Wolfgang!
If I have this example, wich works really fine , I would like to know , how
the same sample works
if i have a link in a footnote and want to write \cite ,with an autor and a
year ? .
\startbuffer[biblio]
@url? , what is next to write, the autor, the year? Or only the link?
}
\stopbuffer
\mainlanguage[en]
\usebtxdataset[biblio.buffer]
\starttext
\startbodymatter
\startchapter[title={Me}]
Your attachment actively impedes the aim that brought you to it
initially
\footnote{\cite[url] [www.contextgarden.net]?
\stopchapter
\stopbodymatter
\startbackmatter
\startchapter[title={Bibliography}]
\placelistofpublications
\stopchapter
\stopbackmatter
\stoptext
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2020-04-02 15:13:43
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https://ls.mathematicstip.com/7422-47-the-mean-value-theorem.html
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4.7: The Mean Value Theorem
The Mean Value Theorem is one of the most important theorems in calculus. First, let’s start with a special case of the Mean Value Theorem, called Rolle’s theorem.
Rolle’s Theorem
Informally, Rolle’s theorem states that if the outputs of a differentiable function (f) are equal at the endpoints of an interval, then there must be an interior point (c) where (f'(c)=0). Figure illustrates this theorem.
Figure (PageIndex{1}): If a differentiable function f satisfies f(a)=f(b), then its derivative must be zero at some point(s) between a and b.
Rolle’s Theorem
Let (f) be a continuous function over the closed interval ([a,b]) and differentiable over the open interval ((a,b)) such that (f(a)=f(b)). There then exists at least one (c∈(a,b)) such that (f'(c)=0.)
Proof
Let (k=f(a)=f(b).) We consider three cases:
1. (f(x)=k) for all (x∈(a,b).)
2. There exists (x∈(a,b)) such that (f(x)>k.)
3. There exists (x∈(a,b)) such that (f(x)
Case 1: If (f(x)=0) for all (x∈(a,b)), then (f'(x)=0) for all (x∈(a,b).)
Case 2: Since (f) is a continuous function over the closed, bounded interval ([a,b]), by the extreme value theorem, it has an absolute maximum. Also, since there is a point (x∈(a,b)) such that (f(x)>k), the absolute maximum is greater than (k). Therefore, the absolute maximum does not occur at either endpoint. As a result, the absolute maximum must occur at an interior point (c∈(a,b)). Because (f) has a maximum at an interior point (c), and (f) is differentiable at (c), by Fermat’s theorem, (f'(c)=0.)
Case 3: The case when there exists a point (x∈(a,b)) such that (f(x)
An important point about Rolle’s theorem is that the differentiability of the function (f) is critical. If f is not differentiable, even at a single point, the result may not hold. For example, the function f(x)=|x|−1 is continuous over ([−1,1]) and (f(−1)=0=f(1)), but (f'(c)≠0) for any (c∈(−1,1)) as shown in the following figure.
Figure (PageIndex{2}): Since (f(x)=|x|−1) is not differentiable at (x=0), the conditions of Rolle’s theorem are not satisfied. In fact, the conclusion does not hold here; there is no (c∈(−1,1)) such that (f'(c)=0.)
Let’s now consider functions that satisfy the conditions of Rolle’s theorem and calculate explicitly the points c where (f'(c)=0.)
Example (PageIndex{1}): Using Rolle’s Theorem
For each of the following functions, verify that the function satisfies the criteria stated in Rolle’s theorem and find all values (c) in the given interval where (f'(c)=0.)
1. (f(x)=x^2+2x) over ([−2,0])
2. (f(x)=x^3−4x) over ([−2,2])
Solution
Since (f) is a polynomial, it is continuous and differentiable everywhere. In addition, (f(−2)=0=f(0).) Therefore, (f) satisfies the criteria of Rolle’s theorem. We conclude that there exists at least one value (c∈(−2,0)) such that (f'(c)=0). Since (f'(x)=2x+2=2(x+1),) we see that (f'(c)=2(c+1)=0) implies (c=−1) as shown in the following graph.
Figure (PageIndex{3}): This function is continuous and differentiable over [−2,0], f'(c)=0 when c=−1.
b. As in part a. (f) is a polynomial and therefore is continuous and differentiable everywhere. Also, (f(−2)=0=f(2).) That said, (f) satisfies the criteria of Rolle’s theorem. Differentiating, we find that (f'(x)=3x^2−4.) Therefore, (f'(c)=0) when (x=±frac{2}{sqrt{3}}). Both points are in the interval ([−2,2]), and, therefore, both points satisfy the conclusion of Rolle’s theorem as shown in the following graph.
Figure (PageIndex{4}): For this polynomial over ([−2,2], f'(c)=0) at (x=±2/sqrt{3}).
Exercise (PageIndex{1})
Verify that the function (f(x)=2x^2−8x+6) defined over the interval ([1,3]) satisfies the conditions of Rolle’s theorem. Find all points (c) guaranteed by Rolle’s theorem.
Hint
Find all values (c), where (f'(c)=0).
(c=2)
The Mean Value Theorem and Its Meaning
Rolle’s theorem is a special case of the Mean Value Theorem. In Rolle’s theorem, we consider differentiable functions (f) that are zero at the endpoints. The Mean Value Theorem generalizes Rolle’s theorem by considering functions that are not necessarily zero at the endpoints. Consequently, we can view the Mean Value Theorem as a slanted version of Rolle’s theorem (Figure). The Mean Value Theorem states that if (f) is continuous over the closed interval ([a,b]) and differentiable over the open interval ((a,b)), then there exists a point (c∈(a,b)) such that the tangent line to the graph of (f) at (c) is parallel to the secant line connecting ((a,f(a))) and ((b,f(b)).)
Figure (PageIndex{5}): The Mean Value Theorem says that for a function that meets its conditions, at some point the tangent line has the same slope as the secant line between the ends. For this function, there are two values (c_1) and (c_2) such that the tangent line to (f) at (c_1) and (c_2) has the same slope as the secant line.
Mean Value Theorem
Let (f) be continuous over the closed interval ([a,b]) and differentiable over the open interval ((a,b)). Then, there exists at least one point (c∈(a,b)) such that
[f'(c)=frac{f(b)−f(a)}{b−a}]
Proof
The proof follows from Rolle’s theorem by introducing an appropriate function that satisfies the criteria of Rolle’s theorem. Consider the line connecting ((a,f(a))) and ((b,f(b)).) Since the slope of that line is
[frac{f(b)−f(a)}{b−a}]
and the line passes through the point ((a,f(a)),) the equation of that line can be written as
[y=frac{f(b)−f(a)}{b−a}(x−a)+f(a).]
Let (g(x)) denote the vertical difference between the point ((x,f(x))) and the point ((x,y)) on that line. Therefore,
[g(x)=f(x)−[frac{f(b)−f(a)}{b−a}(x−a)+f(a)].]
Figure (PageIndex{6}): The value g(x) is the vertical difference between the point (x,f(x)) and the point (x,y) on the secant line connecting (a,f(a)) and (b,f(b)).
Since the graph of (f) intersects the secant line when (x=a) and (x=b), we see that (g(a)=0=g(b)). Since (f) is a differentiable function over ((a,b)), (g) is also a differentiable function over ((a,b)). Furthermore, since (f) is continuous over ([a,b], g) is also continuous over ([a,b]). Therefore, (g) satisfies the criteria of Rolle’s theorem. Consequently, there exists a point (c∈(a,b)) such that (g'(c)=0.) Since
[g'(x)=f'(x)−frac{f(b)−f(a)}{b−a},]
we see that
[g'(c)=f'(c)−frac{f(b)−f(a)}{b−a}.]
Since (g'(c)=0,) we conclude that
[f'(c)=frac{f(b)−f(a)}{b−a}.]
In the next example, we show how the Mean Value Theorem can be applied to the function (f(x)=sqrt{x}) over the interval ([0,9]). The method is the same for other functions, although sometimes with more interesting consequences.
Example (PageIndex{2}): Verifying that the Mean Value Theorem Applies
For (f(x)=sqrt{x}) over the interval ([0,9]), show that (f) satisfies the hypothesis of the Mean Value Theorem, and therefore there exists at least one value (c∈(0,9)) such that (f′(c)) is equal to the slope of the line connecting ((0,f(0))) and ((9,f(9))). Find these values (c) guaranteed by the Mean Value Theorem.
Solution
We know that (f(x)=sqrt{x}) is continuous over ([0,9]) and differentiable over ((0,9).) Therefore, (f) satisfies the hypotheses of the Mean Value Theorem, and there must exist at least one value (c∈(0,9)) such that (f′(c)) is equal to the slope of the line connecting ((0,f(0))) and ((9,f(9))) (Figure). To determine which value(s) of (c) are guaranteed, first calculate the derivative of (f). The derivative (f′(x)=frac{1}{(2sqrt{x})}). The slope of the line connecting ((0,f(0))) and ((9,f(9))) is given by
[frac{f(9)−f(0)}{9−0}=frac{sqrt{9}−sqrt{0}}{9−0}=frac{3}{9}=frac{1}{3}.]
We want to find (c) such that (f′(c)=frac{1}{3}). That is, we want to find (c) such that
[frac{1}{2sqrt{c}}=frac{1}{3}.]
Solving this equation for (c), we obtain (c=frac{9}{4}). At this point, the slope of the tangent line equals the slope of the line joining the endpoints.
Figure (PageIndex{7}): The slope of the tangent line at c=9/4 is the same as the slope of the line segment connecting (0,0) and (9,3).
One application that helps illustrate the Mean Value Theorem involves velocity. For example, suppose we drive a car for 1 h down a straight road with an average velocity of 45 mph. Let (s(t)) and (v(t)) denote the position and velocity of the car, respectively, for (0≤t≤1) h. Assuming that the position function (s(t)) is differentiable, we can apply the Mean Value Theorem to conclude that, at some time (c∈(0,1)), the speed of the car was exactly
[v(c)=s′(c)=frac{s(1)−s(0)}{1−0}=45mph.]
Example (PageIndex{3}): Mean Value Theorem and Velocity
If a rock is dropped from a height of 100 ft, its position (t) seconds after it is dropped until it hits the ground is given by the function (s(t)=−16t^2+100.)
1. Determine how long it takes before the rock hits the ground.
2. Find the average velocity (v_{avg}) of the rock for when the rock is released and the rock hits the ground.
3. Find the time (t) guaranteed by the Mean Value Theorem when the instantaneous velocity of the rock is (v_{avg}.)
Solution
a. When the rock hits the ground, its position is (s(t)=0.) Solving the equation (−16t^2+100=0) for (t), we find that (t=±frac{5}{2}sec). Since we are only considering (t≥0), the ball will hit the ground (frac{5}{2}) sec after it is dropped.
b. The average velocity is given by
(v_{avg}=frac{s(5/2)−s(0)}{5/2−0}=frac{1−100}{5/2}=−40ft/sec.)
c. The instantaneous velocity is given by the derivative of the position function. Therefore, we need to find a time (t) such that (v(t)=s′(t)=vavg=−40ft/sec.) Since s(t) is continuous over the interval ([0,5/2]) and differentiable over the interval ((0,5/2),) by the Mean Value Theorem, there is guaranteed to be a point (c∈(0,5/2)) such that
(s′(c)=frac{s(5/2)−s(0)}{5/2−0}=−40.)
Taking the derivative of the position function (s(t)), we find that (s′(t)=−32t.) Therefore, the equation reduces to (s′(c)=−32c=−40.) Solving this equation for (c), we have (c=frac{5}{4}). Therefore, (frac{5}{4}) sec after the rock is dropped, the instantaneous velocity equals the average velocity of the rock during its free fall: (−40) ft/sec.
Figure (PageIndex{8}): At time (t=5/4) sec, the velocity of the rock is equal to its average velocity from the time it is dropped until it hits the ground.
Exercise (PageIndex{2})
Suppose a ball is dropped from a height of 200 ft. Its position at time (t) is (s(t)=−16t^2+200.) Find the time (t) when the instantaneous velocity of the ball equals its average velocity.
Hint
First, determine how long it takes for the ball to hit the ground. Then, find the average velocity of the ball from the time it is dropped until it hits the ground.
(frac{5}{2sqrt{2}}) sec
Corollaries of the Mean Value Theorem
Let’s now look at three corollaries of the Mean Value Theorem. These results have important consequences, which we use in upcoming sections.
At this point, we know the derivative of any constant function is zero. The Mean Value Theorem allows us to conclude that the converse is also true. In particular, if (f′(x)=0) for all (x) in some interval (I), then (f(x)) is constant over that interval. This result may seem intuitively obvious, but it has important implications that are not obvious, and we discuss them shortly.
Corollary 1: Functions with a Derivative of Zero
Let (f) be differentiable over an interval (I). If (f′(x)=0) for all (x∈I), then (f(x)=) constant for all (x∈I.)
Proof
Since (f) is differentiable over (I), (f) must be continuous over (I). Suppose (f(x)) is not constant for all (x) in (I). Then there exist (a,b∈I), where (a≠b) and (f(a)≠f(b).) Choose the notation so that (a
(frac{f(b)−f(a)}{b−a}≠0.)
Since (f) s a differentiable function, by the Mean Value Theorem, there exists (c∈(a,b)) such that
(f′(c)=frac{f(b)−f(a)}{b−a}).
Therefore, there exists (c∈I) such that (f′(c)≠0), which contradicts the assumption that (f′(x)=0) for all (x∈I).
From Note, it follows that if two functions have the same derivative, they differ by, at most, a constant.
Corollary 2: Constant Difference Theorem
If (f) and (g) are differentiable over an interval (I) and (f′(x)=g′(x)) for all (x∈I), then (f(x)=g(x)+C) for some constant (C).
Proof
Let (h(x)=f(x)−g(x).) Then, (h′(x)=f′(x)−g′(x)=0) for all (x∈I.) By Corollary 1, there is a constant (C) such that (h(x)=C) for all (x∈I). Therefore, (f(x)=g(x)+C) for all (x∈I.)
The third corollary of the Mean Value Theorem discusses when a function is increasing and when it is decreasing. Recall that a function (f) is increasing over (I) if (f(x_1)f(x_2)) whenever (x_1
This fact is important because it means that for a given function (f), if there exists a function (F) such that (F′(x)=f(x)); then, the only other functions that have a derivative equal to (f) are (F(x)+C) for some constant (C). We discuss this result in more detail later in the chapter.
Figure (PageIndex{9}): If a function has a positive derivative over some interval (I), then the function increases over that interval (I); if the derivative is negative over some interval (I), then the function decreases over that interval (I).
Corollary 3: Increasing and Decreasing Functions
Let (f) be continuous over the closed interval ([a,b]) and differentiable over the open interval ((a,b)).
1. If (f′(x)>0) for all (x∈(a,b)), then (f) is an increasing function over ([a,b].)
2. If (f′(x)<0) for all (x∈(a,b)), then (f) is a decreasing function over ([a,b].)
Proof
We will prove i.; the proof of ii. is similar. Suppose (f) is not an increasing function on (I). Then there exist (a) and (b) in (I) such that (a
[f′(c)=frac{f(b)−f(a)}{b−a}.]
Since (f(a)≥f(b)), we know that (f(b)−f(a)≤0). Also, (a0.) We conclude that
[f′(c)=frac{f(b)−f(a)}{b−a}≤0.]
However, (f′(x)>0) for all (x∈I). This is a contradiction, and therefore (f) must be an increasing function over (I).
Key Concepts
• If (f) is continuous over ([a,b]) and differentiable over ((a,b)) and (f(a)=0=f(b)), then there exists a point (c∈(a,b)) such that (f′(c)=0.) This is Rolle’s theorem.
• If (f) is continuous over ([a,b]) and differentiable over ((a,b)), then there exists a point (c∈(a,b)) such that
(f'(c)=frac{f(b)−f(a)}{b−a}.)
This is the Mean Value Theorem.
• If (f'(x)=0) over an interval (I), then (f) is constant over (I).
• If two differentiable functions (f) and (g) satisfy (f′(x)=g′(x)) over (I), then (f(x)=g(x)+C) for some constant (C).
• If (f′(x)>0) over an interval (I), then (f) is increasing over (I). If (f′(x)<0) over (I), then (f) is decreasing over (I).
Glossary
mean value theorem
if (f) is continuous over ([a,b]) and differentiable over ((a,b)), then there exists (c∈(a,b)) such that
(f′(c)=frac{f(b)−f(a)}{b−a})
rolle’s theorem
if (f) is continuous over ([a,b]) and differentiable over ((a,b)), and if (f(a)=f(b)), then there exists (c∈(a,b)) such that (f′(c)=0)
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2021-12-06 16:45:08
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https://solvedlib.com/n/solve-the-following-systems-of-de-in-the-formax-where-a,5200418
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# Solve the following systems of DE in the formAX() where A are given as follows: (40 pts)x(0)7 subject to y(o)]
###### Question:
Solve the following systems of DE in the form AX() where A are given as follows: (40 pts) x(0)7 subject to y(o)] |-[:] (10 pts) A-L-" J (10 pts)
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2022-08-09 23:53:15
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http://www.exim.org/viewvc/pcre/code/trunk/doc/pcrepattern.3?annotate=333&sortby=rev&pathrev=579
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# Contents of /code/trunk/doc/pcrepattern.3
Thu Apr 10 19:55:57 2008 UTC (5 years, 1 month ago) by ph10
File size: 91051 byte(s)
Add Oniguruma syntax \g<...> and \g'...' for subroutine calls.
1 nigel 79 .TH PCREPATTERN 3 2 nigel 63 .SH NAME 3 PCRE - Perl-compatible regular expressions 4 nigel 75 .SH "PCRE REGULAR EXPRESSION DETAILS" 5 nigel 63 .rs 6 .sp 7 ph10 208 The syntax and semantics of the regular expressions that are supported by PCRE 8 are described in detail below. There is a quick-reference syntax summary in the 9 .\" HREF 10 \fBpcresyntax\fP 11 .\" 12 ph10 333 page. PCRE tries to match Perl syntax and semantics as closely as it can. PCRE 13 also supports some alternative regular expression syntax (which does not 14 conflict with the Perl syntax) in order to provide some compatibility with 15 regular expressions in Python, .NET, and Oniguruma. 16 .P 17 Perl's regular expressions are described in its own documentation, and 18 ph10 208 regular expressions in general are covered in a number of books, some of which 19 have copious examples. Jeffrey Friedl's "Mastering Regular Expressions", 20 published by O'Reilly, covers regular expressions in great detail. This 21 description of PCRE's regular expressions is intended as reference material. 22 nigel 75 .P 23 The original operation of PCRE was on strings of one-byte characters. However, 24 there is now also support for UTF-8 character strings. To use this, you must 25 build PCRE to include UTF-8 support, and then call \fBpcre_compile()\fP with 26 the PCRE_UTF8 option. How this affects pattern matching is mentioned in several 27 places below. There is also a summary of UTF-8 features in the 28 nigel 63 .\" HTML 29 .\" 30 section on UTF-8 support 31 .\" 32 in the main 33 .\" HREF 34 nigel 75 \fBpcre\fP 35 nigel 63 .\" 36 page. 37 nigel 75 .P 38 nigel 77 The remainder of this document discusses the patterns that are supported by 39 PCRE when its main matching function, \fBpcre_exec()\fP, is used. 40 From release 6.0, PCRE offers a second matching function, 41 \fBpcre_dfa_exec()\fP, which matches using a different algorithm that is not 42 ph10 172 Perl-compatible. Some of the features discussed below are not available when 43 ph10 168 \fBpcre_dfa_exec()\fP is used. The advantages and disadvantages of the 44 alternative function, and how it differs from the normal function, are 45 discussed in the 46 nigel 77 .\" HREF 47 \fBpcrematching\fP 48 .\" 49 page. 50 nigel 93 . 51 . 52 ph10 227 .SH "NEWLINE CONVENTIONS" 53 .rs 54 .sp 55 PCRE supports five different conventions for indicating line breaks in 56 strings: a single CR (carriage return) character, a single LF (linefeed) 57 character, the two-character sequence CRLF, any of the three preceding, or any 58 Unicode newline sequence. The 59 .\" HREF 60 \fBpcreapi\fP 61 .\" 62 page has 63 .\" HTML 64 .\" 65 further discussion 66 .\" 67 about newlines, and shows how to set the newline convention in the 68 \fIoptions\fP arguments for the compiling and matching functions. 69 .P 70 It is also possible to specify a newline convention by starting a pattern 71 string with one of the following five sequences: 72 .sp 73 (*CR) carriage return 74 (*LF) linefeed 75 (*CRLF) carriage return, followed by linefeed 76 (*ANYCRLF) any of the three above 77 (*ANY) all Unicode newline sequences 78 .sp 79 These override the default and the options given to \fBpcre_compile()\fP. For 80 example, on a Unix system where LF is the default newline sequence, the pattern 81 .sp 82 (*CR)a.b 83 .sp 84 changes the convention to CR. That pattern matches "a\enb" because LF is no 85 longer a newline. Note that these special settings, which are not 86 Perl-compatible, are recognized only at the very start of a pattern, and that 87 ph10 231 they must be in upper case. If more than one of them is present, the last one 88 is used. 89 .P 90 The newline convention does not affect what the \eR escape sequence matches. By 91 default, this is any Unicode newline sequence, for Perl compatibility. However, 92 this can be changed; see the description of \eR in the section entitled 93 .\" HTML 94 .\" 95 "Newline sequences" 96 .\" 97 ph10 247 below. A change of \eR setting can be combined with a change of newline 98 ph10 246 convention. 99 ph10 227 . 100 . 101 nigel 93 .SH "CHARACTERS AND METACHARACTERS" 102 .rs 103 .sp 104 nigel 63 A regular expression is a pattern that is matched against a subject string from 105 left to right. Most characters stand for themselves in a pattern, and match the 106 corresponding characters in the subject. As a trivial example, the pattern 107 nigel 75 .sp 108 nigel 63 The quick brown fox 109 nigel 75 .sp 110 nigel 77 matches a portion of a subject string that is identical to itself. When 111 caseless matching is specified (the PCRE_CASELESS option), letters are matched 112 independently of case. In UTF-8 mode, PCRE always understands the concept of 113 case for characters whose values are less than 128, so caseless matching is 114 always possible. For characters with higher values, the concept of case is 115 supported if PCRE is compiled with Unicode property support, but not otherwise. 116 If you want to use caseless matching for characters 128 and above, you must 117 ensure that PCRE is compiled with Unicode property support as well as with 118 UTF-8 support. 119 .P 120 The power of regular expressions comes from the ability to include alternatives 121 and repetitions in the pattern. These are encoded in the pattern by the use of 122 nigel 75 \fImetacharacters\fP, which do not stand for themselves but instead are 123 nigel 63 interpreted in some special way. 124 nigel 75 .P 125 There are two different sets of metacharacters: those that are recognized 126 nigel 63 anywhere in the pattern except within square brackets, and those that are 127 nigel 93 recognized within square brackets. Outside square brackets, the metacharacters 128 are as follows: 129 nigel 75 .sp 130 \e general escape character with several uses 131 nigel 63 ^ assert start of string (or line, in multiline mode) 132 $assert end of string (or line, in multiline mode) 133 . match any character except newline (by default) 134 [ start character class definition 135 | start of alternative branch 136 ( start subpattern 137 ) end subpattern 138 ? extends the meaning of ( 139 also 0 or 1 quantifier 140 also quantifier minimizer 141 * 0 or more quantifier 142 + 1 or more quantifier 143 also "possessive quantifier" 144 { start min/max quantifier 145 nigel 75 .sp 146 nigel 63 Part of a pattern that is in square brackets is called a "character class". In 147 nigel 75 a character class the only metacharacters are: 148 .sp 149 \e general escape character 150 nigel 63 ^ negate the class, but only if the first character 151 - indicates character range 152 nigel 75 .\" JOIN 153 nigel 63 [ POSIX character class (only if followed by POSIX 154 syntax) 155 ] terminates the character class 156 nigel 75 .sp 157 The following sections describe the use of each of the metacharacters. 158 . 159 nigel 93 . 160 nigel 63 .SH BACKSLASH 161 .rs 162 .sp 163 The backslash character has several uses. Firstly, if it is followed by a 164 nigel 91 non-alphanumeric character, it takes away any special meaning that character 165 may have. This use of backslash as an escape character applies both inside and 166 nigel 63 outside character classes. 167 nigel 75 .P 168 For example, if you want to match a * character, you write \e* in the pattern. 169 nigel 63 This escaping action applies whether or not the following character would 170 nigel 75 otherwise be interpreted as a metacharacter, so it is always safe to precede a 171 non-alphanumeric with backslash to specify that it stands for itself. In 172 particular, if you want to match a backslash, you write \e\e. 173 .P 174 nigel 63 If a pattern is compiled with the PCRE_EXTENDED option, whitespace in the 175 pattern (other than in a character class) and characters between a # outside 176 nigel 91 a character class and the next newline are ignored. An escaping backslash can 177 be used to include a whitespace or # character as part of the pattern. 178 nigel 75 .P 179 nigel 63 If you want to remove the special meaning from a sequence of characters, you 180 nigel 75 can do so by putting them between \eQ and \eE. This is different from Perl in 181 that$ and @ are handled as literals in \eQ...\eE sequences in PCRE, whereas in 182 nigel 63 Perl, $and @ cause variable interpolation. Note the following examples: 183 nigel 75 .sp 184 nigel 63 Pattern PCRE matches Perl matches 185 nigel 75 .sp 186 .\" JOIN 187 \eQabc$xyz\eE abc$xyz abc followed by the 188 nigel 63 contents of$xyz 189 nigel 75 \eQabc\e$xyz\eE abc\e$xyz abc\e$xyz 190 \eQabc\eE\e$\eQxyz\eE abc$xyz abc$xyz 191 .sp 192 The \eQ...\eE sequence is recognized both inside and outside character classes. 193 . 194 . 195 .\" HTML 196 .SS "Non-printing characters" 197 .rs 198 .sp 199 nigel 63 A second use of backslash provides a way of encoding non-printing characters 200 in patterns in a visible manner. There is no restriction on the appearance of 201 non-printing characters, apart from the binary zero that terminates a pattern, 202 but when a pattern is being prepared by text editing, it is usually easier to 203 use one of the following escape sequences than the binary character it 204 represents: 205 nigel 75 .sp 206 \ea alarm, that is, the BEL character (hex 07) 207 \ecx "control-x", where x is any character 208 \ee escape (hex 1B) 209 \ef formfeed (hex 0C) 210 ph10 227 \en linefeed (hex 0A) 211 nigel 75 \er carriage return (hex 0D) 212 \et tab (hex 09) 213 \eddd character with octal code ddd, or backreference 214 \exhh character with hex code hh 215 nigel 87 \ex{hhh..} character with hex code hhh.. 216 nigel 75 .sp 217 The precise effect of \ecx is as follows: if x is a lower case letter, it 218 nigel 63 is converted to upper case. Then bit 6 of the character (hex 40) is inverted. 219 nigel 75 Thus \ecz becomes hex 1A, but \ec{ becomes hex 3B, while \ec; becomes hex 220 nigel 63 7B. 221 nigel 75 .P 222 After \ex, from zero to two hexadecimal digits are read (letters can be in 223 nigel 87 upper or lower case). Any number of hexadecimal digits may appear between \ex{ 224 and }, but the value of the character code must be less than 256 in non-UTF-8 225 ph10 211 mode, and less than 2**31 in UTF-8 mode. That is, the maximum value in 226 hexadecimal is 7FFFFFFF. Note that this is bigger than the largest Unicode code 227 point, which is 10FFFF. 228 nigel 75 .P 229 ph10 211 If characters other than hexadecimal digits appear between \ex{ and }, or if 230 there is no terminating }, this form of escape is not recognized. Instead, the 231 initial \ex will be interpreted as a basic hexadecimal escape, with no 232 following digits, giving a character whose value is zero. 233 .P 234 nigel 63 Characters whose value is less than 256 can be defined by either of the two 235 nigel 87 syntaxes for \ex. There is no difference in the way they are handled. For 236 example, \exdc is exactly the same as \ex{dc}. 237 nigel 75 .P 238 nigel 91 After \e0 up to two further octal digits are read. If there are fewer than two 239 digits, just those that are present are used. Thus the sequence \e0\ex\e07 240 specifies two binary zeros followed by a BEL character (code value 7). Make 241 sure you supply two digits after the initial zero if the pattern character that 242 follows is itself an octal digit. 243 nigel 75 .P 244 nigel 63 The handling of a backslash followed by a digit other than 0 is complicated. 245 Outside a character class, PCRE reads it and any following digits as a decimal 246 number. If the number is less than 10, or if there have been at least that many 247 previous capturing left parentheses in the expression, the entire sequence is 248 nigel 75 taken as a \fIback reference\fP. A description of how this works is given 249 .\" HTML 250 .\" 251 later, 252 .\" 253 following the discussion of 254 .\" HTML 255 .\" 256 parenthesized subpatterns. 257 .\" 258 .P 259 nigel 63 Inside a character class, or if the decimal number is greater than 9 and there 260 have not been that many capturing subpatterns, PCRE re-reads up to three octal 261 nigel 93 digits following the backslash, and uses them to generate a data character. Any 262 nigel 91 subsequent digits stand for themselves. In non-UTF-8 mode, the value of a 263 character specified in octal must be less than \e400. In UTF-8 mode, values up 264 to \e777 are permitted. For example: 265 nigel 75 .sp 266 \e040 is another way of writing a space 267 .\" JOIN 268 \e40 is the same, provided there are fewer than 40 269 nigel 63 previous capturing subpatterns 270 nigel 75 \e7 is always a back reference 271 .\" JOIN 272 \e11 might be a back reference, or another way of 273 nigel 63 writing a tab 274 nigel 75 \e011 is always a tab 275 \e0113 is a tab followed by the character "3" 276 .\" JOIN 277 \e113 might be a back reference, otherwise the 278 nigel 63 character with octal code 113 279 nigel 75 .\" JOIN 280 \e377 might be a back reference, otherwise 281 nigel 63 the byte consisting entirely of 1 bits 282 nigel 75 .\" JOIN 283 \e81 is either a back reference, or a binary zero 284 nigel 63 followed by the two characters "8" and "1" 285 nigel 75 .sp 286 nigel 63 Note that octal values of 100 or greater must not be introduced by a leading 287 zero, because no more than three octal digits are ever read. 288 nigel 75 .P 289 nigel 91 All the sequences that define a single character value can be used both inside 290 and outside character classes. In addition, inside a character class, the 291 sequence \eb is interpreted as the backspace character (hex 08), and the 292 nigel 93 sequences \eR and \eX are interpreted as the characters "R" and "X", 293 respectively. Outside a character class, these sequences have different 294 meanings 295 nigel 75 .\" HTML 296 .\" 297 (see below). 298 .\" 299 . 300 . 301 nigel 93 .SS "Absolute and relative back references" 302 .rs 303 .sp 304 ph10 208 The sequence \eg followed by an unsigned or a negative number, optionally 305 enclosed in braces, is an absolute or relative back reference. A named back 306 reference can be coded as \eg{name}. Back references are discussed 307 nigel 93 .\" HTML 308 .\" 309 later, 310 .\" 311 following the discussion of 312 .\" HTML 313 .\" 314 parenthesized subpatterns. 315 .\" 316 . 317 . 318 ph10 333 .SS "Absolute and relative subroutine calls" 319 .rs 320 .sp 321 For compatibility with Oniguruma, the non-Perl syntax \eg followed by a name or 322 a number enclosed either in angle brackets or single quotes, is an alternative 323 syntax for referencing a subpattern as a "subroutine". Details are discussed 324 .\" HTML 325 .\" 326 later. 327 .\" 328 Note that \eg{...} (Perl syntax) and \eg<...> (Oniguruma syntax) are \fInot\fP 329 synonymous. The former is a back reference; the latter is a subroutine call. 330 . 331 . 332 nigel 75 .SS "Generic character types" 333 .rs 334 .sp 335 nigel 93 Another use of backslash is for specifying generic character types. The 336 nigel 75 following are always recognized: 337 .sp 338 ph10 182 \ed any decimal digit 339 nigel 75 \eD any character that is not a decimal digit 340 ph10 178 \eh any horizontal whitespace character 341 ph10 182 \eH any character that is not a horizontal whitespace character 342 nigel 75 \es any whitespace character 343 \eS any character that is not a whitespace character 344 ph10 178 \ev any vertical whitespace character 345 ph10 182 \eV any character that is not a vertical whitespace character 346 nigel 75 \ew any "word" character 347 \eW any "non-word" character 348 .sp 349 nigel 63 Each pair of escape sequences partitions the complete set of characters into 350 two disjoint sets. Any given character matches one, and only one, of each pair. 351 nigel 75 .P 352 These character type sequences can appear both inside and outside character 353 classes. They each match one character of the appropriate type. If the current 354 matching point is at the end of the subject string, all of them fail, since 355 there is no character to match. 356 .P 357 For compatibility with Perl, \es does not match the VT character (code 11). 358 This makes it different from the the POSIX "space" class. The \es characters 359 ph10 178 are HT (9), LF (10), FF (12), CR (13), and space (32). If "use locale;" is 360 nigel 91 included in a Perl script, \es may match the VT character. In PCRE, it never 361 ph10 178 does. 362 nigel 75 .P 363 ph10 178 In UTF-8 mode, characters with values greater than 128 never match \ed, \es, or 364 \ew, and always match \eD, \eS, and \eW. This is true even when Unicode 365 ph10 182 character property support is available. These sequences retain their original 366 meanings from before UTF-8 support was available, mainly for efficiency 367 ph10 178 reasons. 368 .P 369 ph10 182 The sequences \eh, \eH, \ev, and \eV are Perl 5.10 features. In contrast to the 370 ph10 178 other sequences, these do match certain high-valued codepoints in UTF-8 mode. 371 The horizontal space characters are: 372 .sp 373 U+0009 Horizontal tab 374 U+0020 Space 375 U+00A0 Non-break space 376 U+1680 Ogham space mark 377 U+180E Mongolian vowel separator 378 U+2000 En quad 379 U+2001 Em quad 380 U+2002 En space 381 U+2003 Em space 382 U+2004 Three-per-em space 383 U+2005 Four-per-em space 384 U+2006 Six-per-em space 385 U+2007 Figure space 386 U+2008 Punctuation space 387 U+2009 Thin space 388 U+200A Hair space 389 U+202F Narrow no-break space 390 U+205F Medium mathematical space 391 U+3000 Ideographic space 392 .sp 393 The vertical space characters are: 394 .sp 395 U+000A Linefeed 396 U+000B Vertical tab 397 U+000C Formfeed 398 U+000D Carriage return 399 U+0085 Next line 400 U+2028 Line separator 401 U+2029 Paragraph separator 402 .P 403 nigel 75 A "word" character is an underscore or any character less than 256 that is a 404 letter or digit. The definition of letters and digits is controlled by PCRE's 405 low-valued character tables, and may vary if locale-specific matching is taking 406 place (see 407 nigel 63 .\" HTML 408 .\" 409 "Locale support" 410 .\" 411 in the 412 .\" HREF 413 nigel 75 \fBpcreapi\fP 414 nigel 63 .\" 415 ph10 139 page). For example, in a French locale such as "fr_FR" in Unix-like systems, 416 or "french" in Windows, some character codes greater than 128 are used for 417 ph10 178 accented letters, and these are matched by \ew. The use of locales with Unicode 418 is discouraged. 419 nigel 75 . 420 . 421 ph10 231 .\" HTML 422 nigel 93 .SS "Newline sequences" 423 .rs 424 .sp 425 ph10 231 Outside a character class, by default, the escape sequence \eR matches any 426 Unicode newline sequence. This is a Perl 5.10 feature. In non-UTF-8 mode \eR is 427 equivalent to the following: 428 nigel 93 .sp 429 (?>\er\en|\en|\ex0b|\ef|\er|\ex85) 430 .sp 431 This is an example of an "atomic group", details of which are given 432 .\" HTML 433 .\" 434 below. 435 .\" 436 This particular group matches either the two-character sequence CR followed by 437 LF, or one of the single characters LF (linefeed, U+000A), VT (vertical tab, 438 U+000B), FF (formfeed, U+000C), CR (carriage return, U+000D), or NEL (next 439 line, U+0085). The two-character sequence is treated as a single unit that 440 cannot be split. 441 .P 442 In UTF-8 mode, two additional characters whose codepoints are greater than 255 443 are added: LS (line separator, U+2028) and PS (paragraph separator, U+2029). 444 Unicode character property support is not needed for these characters to be 445 recognized. 446 .P 447 ph10 231 It is possible to restrict \eR to match only CR, LF, or CRLF (instead of the 448 complete set of Unicode line endings) by setting the option PCRE_BSR_ANYCRLF 449 ph10 247 either at compile time or when the pattern is matched. (BSR is an abbrevation 450 ph10 246 for "backslash R".) This can be made the default when PCRE is built; if this is 451 the case, the other behaviour can be requested via the PCRE_BSR_UNICODE option. 452 It is also possible to specify these settings by starting a pattern string with 453 one of the following sequences: 454 ph10 231 .sp 455 (*BSR_ANYCRLF) CR, LF, or CRLF only 456 (*BSR_UNICODE) any Unicode newline sequence 457 .sp 458 These override the default and the options given to \fBpcre_compile()\fP, but 459 they can be overridden by options given to \fBpcre_exec()\fP. Note that these 460 special settings, which are not Perl-compatible, are recognized only at the 461 very start of a pattern, and that they must be in upper case. If more than one 462 ph10 247 of them is present, the last one is used. They can be combined with a change of 463 ph10 246 newline convention, for example, a pattern can start with: 464 .sp 465 (*ANY)(*BSR_ANYCRLF) 466 .sp 467 nigel 93 Inside a character class, \eR matches the letter "R". 468 . 469 . 470 nigel 75 .\" HTML 471 .SS Unicode character properties 472 .rs 473 .sp 474 When PCRE is built with Unicode character property support, three additional 475 ph10 184 escape sequences that match characters with specific properties are available. 476 When not in UTF-8 mode, these sequences are of course limited to testing 477 characters whose codepoints are less than 256, but they do work in this mode. 478 The extra escape sequences are: 479 nigel 75 .sp 480 nigel 87 \ep{\fIxx\fP} a character with the \fIxx\fP property 481 \eP{\fIxx\fP} a character without the \fIxx\fP property 482 \eX an extended Unicode sequence 483 nigel 75 .sp 484 nigel 87 The property names represented by \fIxx\fP above are limited to the Unicode 485 script names, the general category properties, and "Any", which matches any 486 character (including newline). Other properties such as "InMusicalSymbols" are 487 not currently supported by PCRE. Note that \eP{Any} does not match any 488 characters, so always causes a match failure. 489 nigel 75 .P 490 nigel 87 Sets of Unicode characters are defined as belonging to certain scripts. A 491 character from one of these sets can be matched using a script name. For 492 example: 493 nigel 75 .sp 494 nigel 87 \ep{Greek} 495 \eP{Han} 496 .sp 497 Those that are not part of an identified script are lumped together as 498 "Common". The current list of scripts is: 499 .P 500 Arabic, 501 Armenian, 502 nigel 93 Balinese, 503 nigel 87 Bengali, 504 Bopomofo, 505 Braille, 506 Buginese, 507 Buhid, 508 Canadian_Aboriginal, 509 Cherokee, 510 Common, 511 Coptic, 512 nigel 93 Cuneiform, 513 nigel 87 Cypriot, 514 Cyrillic, 515 Deseret, 516 Devanagari, 517 Ethiopic, 518 Georgian, 519 Glagolitic, 520 Gothic, 521 Greek, 522 Gujarati, 523 Gurmukhi, 524 Han, 525 Hangul, 526 Hanunoo, 527 Hebrew, 528 Hiragana, 529 Inherited, 530 Kannada, 531 Katakana, 532 Kharoshthi, 533 Khmer, 534 Lao, 535 Latin, 536 Limbu, 537 Linear_B, 538 Malayalam, 539 Mongolian, 540 Myanmar, 541 New_Tai_Lue, 542 nigel 93 Nko, 543 nigel 87 Ogham, 544 Old_Italic, 545 Old_Persian, 546 Oriya, 547 Osmanya, 548 nigel 93 Phags_Pa, 549 Phoenician, 550 nigel 87 Runic, 551 Shavian, 552 Sinhala, 553 Syloti_Nagri, 554 Syriac, 555 Tagalog, 556 Tagbanwa, 557 Tai_Le, 558 Tamil, 559 Telugu, 560 Thaana, 561 Thai, 562 Tibetan, 563 Tifinagh, 564 Ugaritic, 565 Yi. 566 .P 567 Each character has exactly one general category property, specified by a 568 two-letter abbreviation. For compatibility with Perl, negation can be specified 569 by including a circumflex between the opening brace and the property name. For 570 example, \ep{^Lu} is the same as \eP{Lu}. 571 .P 572 If only one letter is specified with \ep or \eP, it includes all the general 573 category properties that start with that letter. In this case, in the absence 574 of negation, the curly brackets in the escape sequence are optional; these two 575 examples have the same effect: 576 .sp 577 nigel 75 \ep{L} 578 \epL 579 .sp 580 nigel 87 The following general category property codes are supported: 581 nigel 75 .sp 582 C Other 583 Cc Control 584 Cf Format 585 Cn Unassigned 586 Co Private use 587 Cs Surrogate 588 .sp 589 L Letter 590 Ll Lower case letter 591 Lm Modifier letter 592 Lo Other letter 593 Lt Title case letter 594 Lu Upper case letter 595 .sp 596 M Mark 597 Mc Spacing mark 598 Me Enclosing mark 599 Mn Non-spacing mark 600 .sp 601 N Number 602 Nd Decimal number 603 Nl Letter number 604 No Other number 605 .sp 606 P Punctuation 607 Pc Connector punctuation 608 Pd Dash punctuation 609 Pe Close punctuation 610 Pf Final punctuation 611 Pi Initial punctuation 612 Po Other punctuation 613 Ps Open punctuation 614 .sp 615 S Symbol 616 Sc Currency symbol 617 Sk Modifier symbol 618 Sm Mathematical symbol 619 So Other symbol 620 .sp 621 Z Separator 622 Zl Line separator 623 Zp Paragraph separator 624 Zs Space separator 625 .sp 626 nigel 87 The special property L& is also supported: it matches a character that has 627 the Lu, Ll, or Lt property, in other words, a letter that is not classified as 628 a modifier or "other". 629 nigel 75 .P 630 ph10 211 The Cs (Surrogate) property applies only to characters in the range U+D800 to 631 U+DFFF. Such characters are not valid in UTF-8 strings (see RFC 3629) and so 632 cannot be tested by PCRE, unless UTF-8 validity checking has been turned off 633 (see the discussion of PCRE_NO_UTF8_CHECK in the 634 .\" HREF 635 \fBpcreapi\fP 636 .\" 637 page). 638 .P 639 nigel 87 The long synonyms for these properties that Perl supports (such as \ep{Letter}) 640 nigel 91 are not supported by PCRE, nor is it permitted to prefix any of these 641 nigel 87 properties with "Is". 642 .P 643 No character that is in the Unicode table has the Cn (unassigned) property. 644 Instead, this property is assumed for any code point that is not in the 645 Unicode table. 646 .P 647 nigel 75 Specifying caseless matching does not affect these escape sequences. For 648 example, \ep{Lu} always matches only upper case letters. 649 .P 650 The \eX escape matches any number of Unicode characters that form an extended 651 Unicode sequence. \eX is equivalent to 652 .sp 653 (?>\ePM\epM*) 654 .sp 655 That is, it matches a character without the "mark" property, followed by zero 656 or more characters with the "mark" property, and treats the sequence as an 657 atomic group 658 .\" HTML 659 .\" 660 (see below). 661 .\" 662 Characters with the "mark" property are typically accents that affect the 663 ph10 185 preceding character. None of them have codepoints less than 256, so in 664 ph10 184 non-UTF-8 mode \eX matches any one character. 665 nigel 75 .P 666 Matching characters by Unicode property is not fast, because PCRE has to search 667 a structure that contains data for over fifteen thousand characters. That is 668 why the traditional escape sequences such as \ed and \ew do not use Unicode 669 properties in PCRE. 670 . 671 . 672 ph10 168 .\" HTML 673 .SS "Resetting the match start" 674 .rs 675 .sp 676 ph10 172 The escape sequence \eK, which is a Perl 5.10 feature, causes any previously 677 matched characters not to be included in the final matched sequence. For 678 ph10 168 example, the pattern: 679 .sp 680 foo\eKbar 681 .sp 682 ph10 172 matches "foobar", but reports that it has matched "bar". This feature is 683 ph10 168 similar to a lookbehind assertion 684 .\" HTML 685 .\" 686 (described below). 687 .\" 688 ph10 172 However, in this case, the part of the subject before the real match does not 689 have to be of fixed length, as lookbehind assertions do. The use of \eK does 690 ph10 168 not interfere with the setting of 691 .\" HTML 692 .\" 693 captured substrings. 694 ph10 172 .\" 695 ph10 168 For example, when the pattern 696 .sp 697 (foo)\eKbar 698 .sp 699 ph10 172 matches "foobar", the first substring is still set to "foo". 700 ph10 168 . 701 . 702 nigel 75 .\" HTML 703 .SS "Simple assertions" 704 .rs 705 .sp 706 nigel 93 The final use of backslash is for certain simple assertions. An assertion 707 nigel 63 specifies a condition that has to be met at a particular point in a match, 708 without consuming any characters from the subject string. The use of 709 nigel 75 subpatterns for more complicated assertions is described 710 .\" HTML 711 .\" 712 below. 713 .\" 714 nigel 91 The backslashed assertions are: 715 nigel 75 .sp 716 \eb matches at a word boundary 717 \eB matches when not at a word boundary 718 nigel 93 \eA matches at the start of the subject 719 \eZ matches at the end of the subject 720 also matches before a newline at the end of the subject 721 \ez matches only at the end of the subject 722 \eG matches at the first matching position in the subject 723 nigel 75 .sp 724 These assertions may not appear in character classes (but note that \eb has a 725 nigel 63 different meaning, namely the backspace character, inside a character class). 726 nigel 75 .P 727 nigel 63 A word boundary is a position in the subject string where the current character 728 nigel 75 and the previous character do not both match \ew or \eW (i.e. one matches 729 \ew and the other matches \eW), or the start or end of the string if the 730 first or last character matches \ew, respectively. 731 .P 732 The \eA, \eZ, and \ez assertions differ from the traditional circumflex and 733 dollar (described in the next section) in that they only ever match at the very 734 start and end of the subject string, whatever options are set. Thus, they are 735 independent of multiline mode. These three assertions are not affected by the 736 PCRE_NOTBOL or PCRE_NOTEOL options, which affect only the behaviour of the 737 circumflex and dollar metacharacters. However, if the \fIstartoffset\fP 738 argument of \fBpcre_exec()\fP is non-zero, indicating that matching is to start 739 at a point other than the beginning of the subject, \eA can never match. The 740 nigel 91 difference between \eZ and \ez is that \eZ matches before a newline at the end 741 of the string as well as at the very end, whereas \ez matches only at the end. 742 nigel 75 .P 743 The \eG assertion is true only when the current matching position is at the 744 start point of the match, as specified by the \fIstartoffset\fP argument of 745 \fBpcre_exec()\fP. It differs from \eA when the value of \fIstartoffset\fP is 746 non-zero. By calling \fBpcre_exec()\fP multiple times with appropriate 747 nigel 63 arguments, you can mimic Perl's /g option, and it is in this kind of 748 nigel 75 implementation where \eG can be useful. 749 .P 750 Note, however, that PCRE's interpretation of \eG, as the start of the current 751 nigel 63 match, is subtly different from Perl's, which defines it as the end of the 752 previous match. In Perl, these can be different when the previously matched 753 string was empty. Because PCRE does just one match at a time, it cannot 754 reproduce this behaviour. 755 nigel 75 .P 756 If all the alternatives of a pattern begin with \eG, the expression is anchored 757 nigel 63 to the starting match position, and the "anchored" flag is set in the compiled 758 regular expression. 759 nigel 75 . 760 . 761 .SH "CIRCUMFLEX AND DOLLAR" 762 nigel 63 .rs 763 .sp 764 Outside a character class, in the default matching mode, the circumflex 765 nigel 75 character is an assertion that is true only if the current matching point is 766 at the start of the subject string. If the \fIstartoffset\fP argument of 767 \fBpcre_exec()\fP is non-zero, circumflex can never match if the PCRE_MULTILINE 768 nigel 63 option is unset. Inside a character class, circumflex has an entirely different 769 nigel 75 meaning 770 .\" HTML 771 .\" 772 (see below). 773 .\" 774 .P 775 nigel 63 Circumflex need not be the first character of the pattern if a number of 776 alternatives are involved, but it should be the first thing in each alternative 777 in which it appears if the pattern is ever to match that branch. If all 778 possible alternatives start with a circumflex, that is, if the pattern is 779 constrained to match only at the start of the subject, it is said to be an 780 "anchored" pattern. (There are also other constructs that can cause a pattern 781 to be anchored.) 782 nigel 75 .P 783 A dollar character is an assertion that is true only if the current matching 784 nigel 63 point is at the end of the subject string, or immediately before a newline 785 nigel 91 at the end of the string (by default). Dollar need not be the last character of 786 the pattern if a number of alternatives are involved, but it should be the last 787 item in any branch in which it appears. Dollar has no special meaning in a 788 character class. 789 nigel 75 .P 790 nigel 63 The meaning of dollar can be changed so that it matches only at the very end of 791 the string, by setting the PCRE_DOLLAR_ENDONLY option at compile time. This 792 nigel 75 does not affect the \eZ assertion. 793 .P 794 nigel 63 The meanings of the circumflex and dollar characters are changed if the 795 nigel 91 PCRE_MULTILINE option is set. When this is the case, a circumflex matches 796 immediately after internal newlines as well as at the start of the subject 797 string. It does not match after a newline that ends the string. A dollar 798 matches before any newlines in the string, as well as at the very end, when 799 PCRE_MULTILINE is set. When newline is specified as the two-character 800 sequence CRLF, isolated CR and LF characters do not indicate newlines. 801 nigel 75 .P 802 nigel 91 For example, the pattern /^abc$/ matches the subject string "def\enabc" (where 803 \en represents a newline) in multiline mode, but not otherwise. Consequently, 804 patterns that are anchored in single line mode because all branches start with 805 ^ are not anchored in multiline mode, and a match for circumflex is possible 806 when the \fIstartoffset\fP argument of \fBpcre_exec()\fP is non-zero. The 807 PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is set. 808 .P 809 nigel 75 Note that the sequences \eA, \eZ, and \ez can be used to match the start and 810 nigel 63 end of the subject in both modes, and if all branches of a pattern start with 811 nigel 91 \eA it is always anchored, whether or not PCRE_MULTILINE is set. 812 nigel 75 . 813 . 814 .SH "FULL STOP (PERIOD, DOT)" 815 nigel 63 .rs 816 .sp 817 Outside a character class, a dot in the pattern matches any one character in 818 nigel 91 the subject string except (by default) a character that signifies the end of a 819 nigel 93 line. In UTF-8 mode, the matched character may be more than one byte long. 820 nigel 91 .P 821 nigel 93 When a line ending is defined as a single character, dot never matches that 822 character; when the two-character sequence CRLF is used, dot does not match CR 823 if it is immediately followed by LF, but otherwise it matches all characters 824 (including isolated CRs and LFs). When any Unicode line endings are being 825 recognized, dot does not match CR or LF or any of the other line ending 826 characters. 827 .P 828 nigel 91 The behaviour of dot with regard to newlines can be changed. If the PCRE_DOTALL 829 nigel 93 option is set, a dot matches any one character, without exception. If the 830 two-character sequence CRLF is present in the subject string, it takes two dots 831 to match it. 832 nigel 91 .P 833 The handling of dot is entirely independent of the handling of circumflex and 834 dollar, the only relationship being that they both involve newlines. Dot has no 835 special meaning in a character class. 836 nigel 75 . 837 . 838 .SH "MATCHING A SINGLE BYTE" 839 nigel 63 .rs 840 .sp 841 nigel 75 Outside a character class, the escape sequence \eC matches any one byte, both 842 nigel 93 in and out of UTF-8 mode. Unlike a dot, it always matches any line-ending 843 characters. The feature is provided in Perl in order to match individual bytes 844 in UTF-8 mode. Because it breaks up UTF-8 characters into individual bytes, 845 what remains in the string may be a malformed UTF-8 string. For this reason, 846 the \eC escape sequence is best avoided. 847 nigel 75 .P 848 PCRE does not allow \eC to appear in lookbehind assertions 849 .\" HTML 850 .\" 851 (described below), 852 .\" 853 because in UTF-8 mode this would make it impossible to calculate the length of 854 the lookbehind. 855 . 856 . 857 .\" HTML 858 .SH "SQUARE BRACKETS AND CHARACTER CLASSES" 859 nigel 63 .rs 860 .sp 861 An opening square bracket introduces a character class, terminated by a closing 862 square bracket. A closing square bracket on its own is not special. If a 863 closing square bracket is required as a member of the class, it should be the 864 first data character in the class (after an initial circumflex, if present) or 865 escaped with a backslash. 866 nigel 75 .P 867 nigel 63 A character class matches a single character in the subject. In UTF-8 mode, the 868 character may occupy more than one byte. A matched character must be in the set 869 of characters defined by the class, unless the first character in the class 870 definition is a circumflex, in which case the subject character must not be in 871 the set defined by the class. If a circumflex is actually required as a member 872 of the class, ensure it is not the first character, or escape it with a 873 backslash. 874 nigel 75 .P 875 nigel 63 For example, the character class [aeiou] matches any lower case vowel, while 876 [^aeiou] matches any character that is not a lower case vowel. Note that a 877 nigel 75 circumflex is just a convenient notation for specifying the characters that 878 are in the class by enumerating those that are not. A class that starts with a 879 circumflex is not an assertion: it still consumes a character from the subject 880 string, and therefore it fails if the current pointer is at the end of the 881 string. 882 .P 883 nigel 63 In UTF-8 mode, characters with values greater than 255 can be included in a 884 nigel 75 class as a literal string of bytes, or by using the \ex{ escaping mechanism. 885 .P 886 nigel 63 When caseless matching is set, any letters in a class represent both their 887 upper case and lower case versions, so for example, a caseless [aeiou] matches 888 "A" as well as "a", and a caseless [^aeiou] does not match "A", whereas a 889 nigel 77 caseful version would. In UTF-8 mode, PCRE always understands the concept of 890 case for characters whose values are less than 128, so caseless matching is 891 always possible. For characters with higher values, the concept of case is 892 supported if PCRE is compiled with Unicode property support, but not otherwise. 893 If you want to use caseless matching for characters 128 and above, you must 894 ensure that PCRE is compiled with Unicode property support as well as with 895 UTF-8 support. 896 nigel 75 .P 897 nigel 93 Characters that might indicate line breaks are never treated in any special way 898 when matching character classes, whatever line-ending sequence is in use, and 899 whatever setting of the PCRE_DOTALL and PCRE_MULTILINE options is used. A class 900 such as [^a] always matches one of these characters. 901 nigel 75 .P 902 nigel 63 The minus (hyphen) character can be used to specify a range of characters in a 903 character class. For example, [d-m] matches any letter between d and m, 904 inclusive. If a minus character is required in a class, it must be escaped with 905 a backslash or appear in a position where it cannot be interpreted as 906 indicating a range, typically as the first or last character in the class. 907 nigel 75 .P 908 nigel 63 It is not possible to have the literal character "]" as the end character of a 909 range. A pattern such as [W-]46] is interpreted as a class of two characters 910 ("W" and "-") followed by a literal string "46]", so it would match "W46]" or 911 "-46]". However, if the "]" is escaped with a backslash it is interpreted as 912 nigel 75 the end of range, so [W-\e]46] is interpreted as a class containing a range 913 followed by two other characters. The octal or hexadecimal representation of 914 "]" can also be used to end a range. 915 .P 916 nigel 63 Ranges operate in the collating sequence of character values. They can also be 917 nigel 75 used for characters specified numerically, for example [\e000-\e037]. In UTF-8 918 nigel 63 mode, ranges can include characters whose values are greater than 255, for 919 nigel 75 example [\ex{100}-\ex{2ff}]. 920 .P 921 nigel 63 If a range that includes letters is used when caseless matching is set, it 922 matches the letters in either case. For example, [W-c] is equivalent to 923 nigel 75 [][\e\e^_`wxyzabc], matched caselessly, and in non-UTF-8 mode, if character 924 ph10 139 tables for a French locale are in use, [\exc8-\excb] matches accented E 925 nigel 75 characters in both cases. In UTF-8 mode, PCRE supports the concept of case for 926 characters with values greater than 128 only when it is compiled with Unicode 927 property support. 928 .P 929 The character types \ed, \eD, \ep, \eP, \es, \eS, \ew, and \eW may also appear 930 in a character class, and add the characters that they match to the class. For 931 example, [\edABCDEF] matches any hexadecimal digit. A circumflex can 932 nigel 63 conveniently be used with the upper case character types to specify a more 933 restricted set of characters than the matching lower case type. For example, 934 nigel 75 the class [^\eW_] matches any letter or digit, but not underscore. 935 .P 936 The only metacharacters that are recognized in character classes are backslash, 937 hyphen (only where it can be interpreted as specifying a range), circumflex 938 (only at the start), opening square bracket (only when it can be interpreted as 939 introducing a POSIX class name - see the next section), and the terminating 940 closing square bracket. However, escaping other non-alphanumeric characters 941 does no harm. 942 . 943 . 944 .SH "POSIX CHARACTER CLASSES" 945 nigel 63 .rs 946 .sp 947 nigel 75 Perl supports the POSIX notation for character classes. This uses names 948 nigel 63 enclosed by [: and :] within the enclosing square brackets. PCRE also supports 949 this notation. For example, 950 nigel 75 .sp 951 nigel 63 [01[:alpha:]%] 952 nigel 75 .sp 953 nigel 63 matches "0", "1", any alphabetic character, or "%". The supported class names 954 are 955 nigel 75 .sp 956 nigel 63 alnum letters and digits 957 alpha letters 958 ascii character codes 0 - 127 959 blank space or tab only 960 cntrl control characters 961 nigel 75 digit decimal digits (same as \ed) 962 nigel 63 graph printing characters, excluding space 963 lower lower case letters 964 print printing characters, including space 965 punct printing characters, excluding letters and digits 966 nigel 75 space white space (not quite the same as \es) 967 nigel 63 upper upper case letters 968 nigel 75 word "word" characters (same as \ew) 969 nigel 63 xdigit hexadecimal digits 970 nigel 75 .sp 971 nigel 63 The "space" characters are HT (9), LF (10), VT (11), FF (12), CR (13), and 972 space (32). Notice that this list includes the VT character (code 11). This 973 nigel 75 makes "space" different to \es, which does not include VT (for Perl 974 nigel 63 compatibility). 975 nigel 75 .P 976 nigel 63 The name "word" is a Perl extension, and "blank" is a GNU extension from Perl 977 5.8. Another Perl extension is negation, which is indicated by a ^ character 978 after the colon. For example, 979 nigel 75 .sp 980 nigel 63 [12[:^digit:]] 981 nigel 75 .sp 982 nigel 63 matches "1", "2", or any non-digit. PCRE (and Perl) also recognize the POSIX 983 syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not 984 supported, and an error is given if they are encountered. 985 nigel 75 .P 986 In UTF-8 mode, characters with values greater than 128 do not match any of 987 nigel 63 the POSIX character classes. 988 nigel 75 . 989 . 990 .SH "VERTICAL BAR" 991 nigel 63 .rs 992 .sp 993 Vertical bar characters are used to separate alternative patterns. For example, 994 the pattern 995 nigel 75 .sp 996 nigel 63 gilbert|sullivan 997 nigel 75 .sp 998 nigel 63 matches either "gilbert" or "sullivan". Any number of alternatives may appear, 999 nigel 91 and an empty alternative is permitted (matching the empty string). The matching 1000 process tries each alternative in turn, from left to right, and the first one 1001 that succeeds is used. If the alternatives are within a subpattern 1002 nigel 75 .\" HTML 1003 .\" 1004 (defined below), 1005 .\" 1006 "succeeds" means matching the rest of the main pattern as well as the 1007 alternative in the subpattern. 1008 . 1009 . 1010 .SH "INTERNAL OPTION SETTING" 1011 nigel 63 .rs 1012 .sp 1013 The settings of the PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and 1014 ph10 231 PCRE_EXTENDED options (which are Perl-compatible) can be changed from within 1015 the pattern by a sequence of Perl option letters enclosed between "(?" and ")". 1016 The option letters are 1017 nigel 75 .sp 1018 nigel 63 i for PCRE_CASELESS 1019 m for PCRE_MULTILINE 1020 s for PCRE_DOTALL 1021 x for PCRE_EXTENDED 1022 nigel 75 .sp 1023 nigel 63 For example, (?im) sets caseless, multiline matching. It is also possible to 1024 unset these options by preceding the letter with a hyphen, and a combined 1025 setting and unsetting such as (?im-sx), which sets PCRE_CASELESS and 1026 PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED, is also 1027 permitted. If a letter appears both before and after the hyphen, the option is 1028 unset. 1029 nigel 75 .P 1030 ph10 231 The PCRE-specific options PCRE_DUPNAMES, PCRE_UNGREEDY, and PCRE_EXTRA can be 1031 changed in the same way as the Perl-compatible options by using the characters 1032 J, U and X respectively. 1033 .P 1034 nigel 63 When an option change occurs at top level (that is, not inside subpattern 1035 parentheses), the change applies to the remainder of the pattern that follows. 1036 If the change is placed right at the start of a pattern, PCRE extracts it into 1037 the global options (and it will therefore show up in data extracted by the 1038 nigel 75 \fBpcre_fullinfo()\fP function). 1039 .P 1040 nigel 93 An option change within a subpattern (see below for a description of 1041 subpatterns) affects only that part of the current pattern that follows it, so 1042 nigel 75 .sp 1043 nigel 63 (a(?i)b)c 1044 nigel 75 .sp 1045 nigel 63 matches abc and aBc and no other strings (assuming PCRE_CASELESS is not used). 1046 By this means, options can be made to have different settings in different 1047 parts of the pattern. Any changes made in one alternative do carry on 1048 into subsequent branches within the same subpattern. For example, 1049 nigel 75 .sp 1050 nigel 63 (a(?i)b|c) 1051 nigel 75 .sp 1052 nigel 63 matches "ab", "aB", "c", and "C", even though when matching "C" the first 1053 branch is abandoned before the option setting. This is because the effects of 1054 option settings happen at compile time. There would be some very weird 1055 behaviour otherwise. 1056 ph10 251 .P 1057 \fBNote:\fP There are other PCRE-specific options that can be set by the 1058 application when the compile or match functions are called. In some cases the 1059 pattern can contain special leading sequences to override what the application 1060 has set or what has been defaulted. Details are given in the section entitled 1061 .\" HTML 1062 .\" 1063 "Newline sequences" 1064 .\" 1065 ph10 259 above. 1066 nigel 75 . 1067 . 1068 .\" HTML 1069 nigel 63 .SH SUBPATTERNS 1070 .rs 1071 .sp 1072 Subpatterns are delimited by parentheses (round brackets), which can be nested. 1073 nigel 75 Turning part of a pattern into a subpattern does two things: 1074 .sp 1075 nigel 63 1. It localizes a set of alternatives. For example, the pattern 1076 nigel 75 .sp 1077 nigel 63 cat(aract|erpillar|) 1078 nigel 75 .sp 1079 nigel 63 matches one of the words "cat", "cataract", or "caterpillar". Without the 1080 nigel 93 parentheses, it would match "cataract", "erpillar" or an empty string. 1081 nigel 75 .sp 1082 2. It sets up the subpattern as a capturing subpattern. This means that, when 1083 the whole pattern matches, that portion of the subject string that matched the 1084 subpattern is passed back to the caller via the \fIovector\fP argument of 1085 \fBpcre_exec()\fP. Opening parentheses are counted from left to right (starting 1086 from 1) to obtain numbers for the capturing subpatterns. 1087 .P 1088 nigel 63 For example, if the string "the red king" is matched against the pattern 1089 nigel 75 .sp 1090 nigel 63 the ((red|white) (king|queen)) 1091 nigel 75 .sp 1092 nigel 63 the captured substrings are "red king", "red", and "king", and are numbered 1, 1093 2, and 3, respectively. 1094 nigel 75 .P 1095 nigel 63 The fact that plain parentheses fulfil two functions is not always helpful. 1096 There are often times when a grouping subpattern is required without a 1097 capturing requirement. If an opening parenthesis is followed by a question mark 1098 and a colon, the subpattern does not do any capturing, and is not counted when 1099 computing the number of any subsequent capturing subpatterns. For example, if 1100 the string "the white queen" is matched against the pattern 1101 nigel 75 .sp 1102 nigel 63 the ((?:red|white) (king|queen)) 1103 nigel 75 .sp 1104 nigel 63 the captured substrings are "white queen" and "queen", and are numbered 1 and 1105 nigel 93 2. The maximum number of capturing subpatterns is 65535. 1106 nigel 75 .P 1107 nigel 63 As a convenient shorthand, if any option settings are required at the start of 1108 a non-capturing subpattern, the option letters may appear between the "?" and 1109 the ":". Thus the two patterns 1110 nigel 75 .sp 1111 nigel 63 (?i:saturday|sunday) 1112 (?:(?i)saturday|sunday) 1113 nigel 75 .sp 1114 nigel 63 match exactly the same set of strings. Because alternative branches are tried 1115 from left to right, and options are not reset until the end of the subpattern 1116 is reached, an option setting in one branch does affect subsequent branches, so 1117 the above patterns match "SUNDAY" as well as "Saturday". 1118 nigel 75 . 1119 . 1120 ph10 175 .SH "DUPLICATE SUBPATTERN NUMBERS" 1121 .rs 1122 .sp 1123 ph10 182 Perl 5.10 introduced a feature whereby each alternative in a subpattern uses 1124 the same numbers for its capturing parentheses. Such a subpattern starts with 1125 (?| and is itself a non-capturing subpattern. For example, consider this 1126 ph10 175 pattern: 1127 .sp 1128 (?|(Sat)ur|(Sun))day 1129 ph10 182 .sp 1130 Because the two alternatives are inside a (?| group, both sets of capturing 1131 parentheses are numbered one. Thus, when the pattern matches, you can look 1132 at captured substring number one, whichever alternative matched. This construct 1133 is useful when you want to capture part, but not all, of one of a number of 1134 alternatives. Inside a (?| group, parentheses are numbered as usual, but the 1135 ph10 175 number is reset at the start of each branch. The numbers of any capturing 1136 ph10 182 buffers that follow the subpattern start after the highest number used in any 1137 branch. The following example is taken from the Perl documentation. 1138 ph10 175 The numbers underneath show in which buffer the captured content will be 1139 stored. 1140 .sp 1141 # before ---------------branch-reset----------- after 1142 / ( a ) (?| x ( y ) z | (p (q) r) | (t) u (v) ) ( z ) /x 1143 # 1 2 2 3 2 3 4 1144 ph10 182 .sp 1145 ph10 175 A backreference or a recursive call to a numbered subpattern always refers to 1146 the first one in the pattern with the given number. 1147 .P 1148 An alternative approach to using this "branch reset" feature is to use 1149 duplicate named subpatterns, as described in the next section. 1150 . 1151 . 1152 nigel 75 .SH "NAMED SUBPATTERNS" 1153 nigel 63 .rs 1154 .sp 1155 Identifying capturing parentheses by number is simple, but it can be very hard 1156 to keep track of the numbers in complicated regular expressions. Furthermore, 1157 nigel 75 if an expression is modified, the numbers may change. To help with this 1158 nigel 93 difficulty, PCRE supports the naming of subpatterns. This feature was not 1159 added to Perl until release 5.10. Python had the feature earlier, and PCRE 1160 introduced it at release 4.0, using the Python syntax. PCRE now supports both 1161 the Perl and the Python syntax. 1162 .P 1163 In PCRE, a subpattern can be named in one of three ways: (?...) or 1164 (?'name'...) as in Perl, or (?P...) as in Python. References to capturing 1165 nigel 91 parentheses from other parts of the pattern, such as 1166 .\" HTML 1167 .\" 1168 backreferences, 1169 .\" 1170 .\" HTML 1171 .\" 1172 recursion, 1173 .\" 1174 and 1175 .\" HTML 1176 .\" 1177 conditions, 1178 .\" 1179 can be made by name as well as by number. 1180 nigel 75 .P 1181 nigel 91 Names consist of up to 32 alphanumeric characters and underscores. Named 1182 nigel 93 capturing parentheses are still allocated numbers as well as names, exactly as 1183 if the names were not present. The PCRE API provides function calls for 1184 extracting the name-to-number translation table from a compiled pattern. There 1185 is also a convenience function for extracting a captured substring by name. 1186 nigel 91 .P 1187 By default, a name must be unique within a pattern, but it is possible to relax 1188 this constraint by setting the PCRE_DUPNAMES option at compile time. This can 1189 be useful for patterns where only one instance of the named parentheses can 1190 match. Suppose you want to match the name of a weekday, either as a 3-letter 1191 abbreviation or as the full name, and in both cases you want to extract the 1192 abbreviation. This pattern (ignoring the line breaks) does the job: 1193 .sp 1194 nigel 93 (?Mon|Fri|Sun)(?:day)?| 1195 (?Tue)(?:sday)?| 1196 (?Wed)(?:nesday)?| 1197 (?Thu)(?:rsday)?| 1198 (?Sat)(?:urday)? 1199 nigel 91 .sp 1200 There are five capturing substrings, but only one is ever set after a match. 1201 ph10 182 (An alternative way of solving this problem is to use a "branch reset" 1202 ph10 175 subpattern, as described in the previous section.) 1203 .P 1204 nigel 91 The convenience function for extracting the data by name returns the substring 1205 nigel 93 for the first (and in this example, the only) subpattern of that name that 1206 nigel 91 matched. This saves searching to find which numbered subpattern it was. If you 1207 make a reference to a non-unique named subpattern from elsewhere in the 1208 pattern, the one that corresponds to the lowest number is used. For further 1209 details of the interfaces for handling named subpatterns, see the 1210 nigel 63 .\" HREF 1211 nigel 75 \fBpcreapi\fP 1212 nigel 63 .\" 1213 documentation. 1214 nigel 75 . 1215 . 1216 nigel 63 .SH REPETITION 1217 .rs 1218 .sp 1219 Repetition is specified by quantifiers, which can follow any of the following 1220 items: 1221 nigel 75 .sp 1222 nigel 63 a literal data character 1223 nigel 93 the dot metacharacter 1224 nigel 75 the \eC escape sequence 1225 the \eX escape sequence (in UTF-8 mode with Unicode properties) 1226 nigel 93 the \eR escape sequence 1227 nigel 75 an escape such as \ed that matches a single character 1228 nigel 63 a character class 1229 a back reference (see next section) 1230 a parenthesized subpattern (unless it is an assertion) 1231 nigel 75 .sp 1232 nigel 63 The general repetition quantifier specifies a minimum and maximum number of 1233 permitted matches, by giving the two numbers in curly brackets (braces), 1234 separated by a comma. The numbers must be less than 65536, and the first must 1235 be less than or equal to the second. For example: 1236 nigel 75 .sp 1237 nigel 63 z{2,4} 1238 nigel 75 .sp 1239 nigel 63 matches "zz", "zzz", or "zzzz". A closing brace on its own is not a special 1240 character. If the second number is omitted, but the comma is present, there is 1241 no upper limit; if the second number and the comma are both omitted, the 1242 quantifier specifies an exact number of required matches. Thus 1243 nigel 75 .sp 1244 nigel 63 [aeiou]{3,} 1245 nigel 75 .sp 1246 nigel 63 matches at least 3 successive vowels, but may match many more, while 1247 nigel 75 .sp 1248 \ed{8} 1249 .sp 1250 nigel 63 matches exactly 8 digits. An opening curly bracket that appears in a position 1251 where a quantifier is not allowed, or one that does not match the syntax of a 1252 quantifier, is taken as a literal character. For example, {,6} is not a 1253 quantifier, but a literal string of four characters. 1254 nigel 75 .P 1255 nigel 63 In UTF-8 mode, quantifiers apply to UTF-8 characters rather than to individual 1256 nigel 75 bytes. Thus, for example, \ex{100}{2} matches two UTF-8 characters, each of 1257 which is represented by a two-byte sequence. Similarly, when Unicode property 1258 support is available, \eX{3} matches three Unicode extended sequences, each of 1259 which may be several bytes long (and they may be of different lengths). 1260 .P 1261 nigel 63 The quantifier {0} is permitted, causing the expression to behave as if the 1262 previous item and the quantifier were not present. 1263 nigel 75 .P 1264 nigel 93 For convenience, the three most common quantifiers have single-character 1265 abbreviations: 1266 nigel 75 .sp 1267 nigel 63 * is equivalent to {0,} 1268 + is equivalent to {1,} 1269 ? is equivalent to {0,1} 1270 nigel 75 .sp 1271 nigel 63 It is possible to construct infinite loops by following a subpattern that can 1272 match no characters with a quantifier that has no upper limit, for example: 1273 nigel 75 .sp 1274 nigel 63 (a?)* 1275 nigel 75 .sp 1276 nigel 63 Earlier versions of Perl and PCRE used to give an error at compile time for 1277 such patterns. However, because there are cases where this can be useful, such 1278 patterns are now accepted, but if any repetition of the subpattern does in fact 1279 match no characters, the loop is forcibly broken. 1280 nigel 75 .P 1281 nigel 63 By default, the quantifiers are "greedy", that is, they match as much as 1282 possible (up to the maximum number of permitted times), without causing the 1283 rest of the pattern to fail. The classic example of where this gives problems 1284 nigel 75 is in trying to match comments in C programs. These appear between /* and */ 1285 and within the comment, individual * and / characters may appear. An attempt to 1286 match C comments by applying the pattern 1287 .sp 1288 /\e*.*\e*/ 1289 .sp 1290 nigel 63 to the string 1291 nigel 75 .sp 1292 /* first comment */ not comment /* second comment */ 1293 .sp 1294 nigel 63 fails, because it matches the entire string owing to the greediness of the .* 1295 item. 1296 nigel 75 .P 1297 nigel 63 However, if a quantifier is followed by a question mark, it ceases to be 1298 greedy, and instead matches the minimum number of times possible, so the 1299 pattern 1300 nigel 75 .sp 1301 /\e*.*?\e*/ 1302 .sp 1303 nigel 63 does the right thing with the C comments. The meaning of the various 1304 quantifiers is not otherwise changed, just the preferred number of matches. 1305 Do not confuse this use of question mark with its use as a quantifier in its 1306 own right. Because it has two uses, it can sometimes appear doubled, as in 1307 nigel 75 .sp 1308 \ed??\ed 1309 .sp 1310 nigel 63 which matches one digit by preference, but can match two if that is the only 1311 way the rest of the pattern matches. 1312 nigel 75 .P 1313 nigel 93 If the PCRE_UNGREEDY option is set (an option that is not available in Perl), 1314 nigel 63 the quantifiers are not greedy by default, but individual ones can be made 1315 greedy by following them with a question mark. In other words, it inverts the 1316 default behaviour. 1317 nigel 75 .P 1318 nigel 63 When a parenthesized subpattern is quantified with a minimum repeat count that 1319 nigel 75 is greater than 1 or with a limited maximum, more memory is required for the 1320 nigel 63 compiled pattern, in proportion to the size of the minimum or maximum. 1321 nigel 75 .P 1322 nigel 63 If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equivalent 1323 nigel 93 to Perl's /s) is set, thus allowing the dot to match newlines, the pattern is 1324 nigel 63 implicitly anchored, because whatever follows will be tried against every 1325 character position in the subject string, so there is no point in retrying the 1326 overall match at any position after the first. PCRE normally treats such a 1327 nigel 75 pattern as though it were preceded by \eA. 1328 .P 1329 nigel 63 In cases where it is known that the subject string contains no newlines, it is 1330 worth setting PCRE_DOTALL in order to obtain this optimization, or 1331 alternatively using ^ to indicate anchoring explicitly. 1332 nigel 75 .P 1333 nigel 63 However, there is one situation where the optimization cannot be used. When .* 1334 is inside capturing parentheses that are the subject of a backreference 1335 nigel 93 elsewhere in the pattern, a match at the start may fail where a later one 1336 succeeds. Consider, for example: 1337 nigel 75 .sp 1338 (.*)abc\e1 1339 .sp 1340 nigel 63 If the subject is "xyz123abc123" the match point is the fourth character. For 1341 this reason, such a pattern is not implicitly anchored. 1342 nigel 75 .P 1343 nigel 63 When a capturing subpattern is repeated, the value captured is the substring 1344 that matched the final iteration. For example, after 1345 nigel 75 .sp 1346 (tweedle[dume]{3}\es*)+ 1347 .sp 1348 nigel 63 has matched "tweedledum tweedledee" the value of the captured substring is 1349 "tweedledee". However, if there are nested capturing subpatterns, the 1350 corresponding captured values may have been set in previous iterations. For 1351 example, after 1352 nigel 75 .sp 1353 nigel 63 /(a|(b))+/ 1354 nigel 75 .sp 1355 nigel 63 matches "aba" the value of the second captured substring is "b". 1356 nigel 75 . 1357 . 1358 .\" HTML 1359 .SH "ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS" 1360 nigel 63 .rs 1361 .sp 1362 nigel 93 With both maximizing ("greedy") and minimizing ("ungreedy" or "lazy") 1363 repetition, failure of what follows normally causes the repeated item to be 1364 re-evaluated to see if a different number of repeats allows the rest of the 1365 pattern to match. Sometimes it is useful to prevent this, either to change the 1366 nature of the match, or to cause it fail earlier than it otherwise might, when 1367 the author of the pattern knows there is no point in carrying on. 1368 nigel 75 .P 1369 Consider, for example, the pattern \ed+foo when applied to the subject line 1370 .sp 1371 nigel 63 123456bar 1372 nigel 75 .sp 1373 nigel 63 After matching all 6 digits and then failing to match "foo", the normal 1374 nigel 75 action of the matcher is to try again with only 5 digits matching the \ed+ 1375 nigel 63 item, and then with 4, and so on, before ultimately failing. "Atomic grouping" 1376 (a term taken from Jeffrey Friedl's book) provides the means for specifying 1377 that once a subpattern has matched, it is not to be re-evaluated in this way. 1378 nigel 75 .P 1379 nigel 93 If we use atomic grouping for the previous example, the matcher gives up 1380 nigel 63 immediately on failing to match "foo" the first time. The notation is a kind of 1381 special parenthesis, starting with (?> as in this example: 1382 nigel 75 .sp 1383 (?>\ed+)foo 1384 .sp 1385 nigel 63 This kind of parenthesis "locks up" the part of the pattern it contains once 1386 it has matched, and a failure further into the pattern is prevented from 1387 backtracking into it. Backtracking past it to previous items, however, works as 1388 normal. 1389 nigel 75 .P 1390 nigel 63 An alternative description is that a subpattern of this type matches the string 1391 of characters that an identical standalone pattern would match, if anchored at 1392 the current point in the subject string. 1393 nigel 75 .P 1394 nigel 63 Atomic grouping subpatterns are not capturing subpatterns. Simple cases such as 1395 the above example can be thought of as a maximizing repeat that must swallow 1396 nigel 75 everything it can. So, while both \ed+ and \ed+? are prepared to adjust the 1397 nigel 63 number of digits they match in order to make the rest of the pattern match, 1398 nigel 75 (?>\ed+) can only match an entire sequence of digits. 1399 .P 1400 nigel 63 Atomic groups in general can of course contain arbitrarily complicated 1401 subpatterns, and can be nested. However, when the subpattern for an atomic 1402 group is just a single repeated item, as in the example above, a simpler 1403 notation, called a "possessive quantifier" can be used. This consists of an 1404 additional + character following a quantifier. Using this notation, the 1405 previous example can be rewritten as 1406 nigel 75 .sp 1407 \ed++foo 1408 .sp 1409 ph10 208 Note that a possessive quantifier can be used with an entire group, for 1410 example: 1411 .sp 1412 (abc|xyz){2,3}+ 1413 .sp 1414 nigel 63 Possessive quantifiers are always greedy; the setting of the PCRE_UNGREEDY 1415 option is ignored. They are a convenient notation for the simpler forms of 1416 nigel 93 atomic group. However, there is no difference in the meaning of a possessive 1417 quantifier and the equivalent atomic group, though there may be a performance 1418 difference; possessive quantifiers should be slightly faster. 1419 nigel 75 .P 1420 nigel 93 The possessive quantifier syntax is an extension to the Perl 5.8 syntax. 1421 Jeffrey Friedl originated the idea (and the name) in the first edition of his 1422 book. Mike McCloskey liked it, so implemented it when he built Sun's Java 1423 package, and PCRE copied it from there. It ultimately found its way into Perl 1424 at release 5.10. 1425 nigel 75 .P 1426 nigel 93 PCRE has an optimization that automatically "possessifies" certain simple 1427 pattern constructs. For example, the sequence A+B is treated as A++B because 1428 there is no point in backtracking into a sequence of A's when B must follow. 1429 .P 1430 nigel 63 When a pattern contains an unlimited repeat inside a subpattern that can itself 1431 be repeated an unlimited number of times, the use of an atomic group is the 1432 only way to avoid some failing matches taking a very long time indeed. The 1433 pattern 1434 nigel 75 .sp 1435 (\eD+|<\ed+>)*[!?] 1436 .sp 1437 nigel 63 matches an unlimited number of substrings that either consist of non-digits, or 1438 digits enclosed in <>, followed by either ! or ?. When it matches, it runs 1439 quickly. However, if it is applied to 1440 nigel 75 .sp 1441 nigel 63 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 1442 nigel 75 .sp 1443 nigel 63 it takes a long time before reporting failure. This is because the string can 1444 nigel 75 be divided between the internal \eD+ repeat and the external * repeat in a 1445 large number of ways, and all have to be tried. (The example uses [!?] rather 1446 than a single character at the end, because both PCRE and Perl have an 1447 optimization that allows for fast failure when a single character is used. They 1448 remember the last single character that is required for a match, and fail early 1449 if it is not present in the string.) If the pattern is changed so that it uses 1450 an atomic group, like this: 1451 .sp 1452 ((?>\eD+)|<\ed+>)*[!?] 1453 .sp 1454 nigel 63 sequences of non-digits cannot be broken, and failure happens quickly. 1455 nigel 75 . 1456 . 1457 .\" HTML 1458 .SH "BACK REFERENCES" 1459 nigel 63 .rs 1460 .sp 1461 Outside a character class, a backslash followed by a digit greater than 0 (and 1462 possibly further digits) is a back reference to a capturing subpattern earlier 1463 (that is, to its left) in the pattern, provided there have been that many 1464 previous capturing left parentheses. 1465 nigel 75 .P 1466 nigel 63 However, if the decimal number following the backslash is less than 10, it is 1467 always taken as a back reference, and causes an error only if there are not 1468 that many capturing left parentheses in the entire pattern. In other words, the 1469 parentheses that are referenced need not be to the left of the reference for 1470 nigel 91 numbers less than 10. A "forward back reference" of this type can make sense 1471 when a repetition is involved and the subpattern to the right has participated 1472 in an earlier iteration. 1473 .P 1474 nigel 93 It is not possible to have a numerical "forward back reference" to a subpattern 1475 whose number is 10 or more using this syntax because a sequence such as \e50 is 1476 interpreted as a character defined in octal. See the subsection entitled 1477 nigel 91 "Non-printing characters" 1478 nigel 75 .\" HTML 1479 .\" 1480 above 1481 .\" 1482 nigel 93 for further details of the handling of digits following a backslash. There is 1483 no such problem when named parentheses are used. A back reference to any 1484 subpattern is possible using named parentheses (see below). 1485 nigel 75 .P 1486 nigel 93 Another way of avoiding the ambiguity inherent in the use of digits following a 1487 backslash is to use the \eg escape sequence, which is a feature introduced in 1488 ph10 208 Perl 5.10. This escape must be followed by an unsigned number or a negative 1489 number, optionally enclosed in braces. These examples are all identical: 1490 nigel 93 .sp 1491 (ring), \e1 1492 (ring), \eg1 1493 (ring), \eg{1} 1494 .sp 1495 ph10 208 An unsigned number specifies an absolute reference without the ambiguity that 1496 is present in the older syntax. It is also useful when literal digits follow 1497 the reference. A negative number is a relative reference. Consider this 1498 example: 1499 nigel 93 .sp 1500 (abc(def)ghi)\eg{-1} 1501 .sp 1502 The sequence \eg{-1} is a reference to the most recently started capturing 1503 subpattern before \eg, that is, is it equivalent to \e2. Similarly, \eg{-2} 1504 would be equivalent to \e1. The use of relative references can be helpful in 1505 long patterns, and also in patterns that are created by joining together 1506 fragments that contain references within themselves. 1507 .P 1508 nigel 63 A back reference matches whatever actually matched the capturing subpattern in 1509 the current subject string, rather than anything matching the subpattern 1510 itself (see 1511 .\" HTML 1512 .\" 1513 "Subpatterns as subroutines" 1514 .\" 1515 below for a way of doing that). So the pattern 1516 nigel 75 .sp 1517 (sens|respons)e and \e1ibility 1518 .sp 1519 nigel 63 matches "sense and sensibility" and "response and responsibility", but not 1520 "sense and responsibility". If caseful matching is in force at the time of the 1521 back reference, the case of letters is relevant. For example, 1522 nigel 75 .sp 1523 ((?i)rah)\es+\e1 1524 .sp 1525 nigel 63 matches "rah rah" and "RAH RAH", but not "RAH rah", even though the original 1526 capturing subpattern is matched caselessly. 1527 nigel 75 .P 1528 ph10 171 There are several different ways of writing back references to named 1529 subpatterns. The .NET syntax \ek{name} and the Perl syntax \ek or 1530 \ek'name' are supported, as is the Python syntax (?P=name). Perl 5.10's unified 1531 back reference syntax, in which \eg can be used for both numeric and named 1532 references, is also supported. We could rewrite the above example in any of 1533 nigel 93 the following ways: 1534 nigel 75 .sp 1535 nigel 93 (?(?i)rah)\es+\ek 1536 ph10 171 (?'p1'(?i)rah)\es+\ek{p1} 1537 nigel 91 (?P(?i)rah)\es+(?P=p1) 1538 ph10 171 (?(?i)rah)\es+\eg{p1} 1539 nigel 75 .sp 1540 nigel 91 A subpattern that is referenced by name may appear in the pattern before or 1541 after the reference. 1542 .P 1543 nigel 63 There may be more than one back reference to the same subpattern. If a 1544 subpattern has not actually been used in a particular match, any back 1545 references to it always fail. For example, the pattern 1546 nigel 75 .sp 1547 (a|(bc))\e2 1548 .sp 1549 nigel 63 always fails if it starts to match "a" rather than "bc". Because there may be 1550 many capturing parentheses in a pattern, all digits following the backslash are 1551 taken as part of a potential back reference number. If the pattern continues 1552 with a digit character, some delimiter must be used to terminate the back 1553 reference. If the PCRE_EXTENDED option is set, this can be whitespace. 1554 nigel 75 Otherwise an empty comment (see 1555 .\" HTML 1556 .\" 1557 "Comments" 1558 .\" 1559 below) can be used. 1560 .P 1561 nigel 63 A back reference that occurs inside the parentheses to which it refers fails 1562 nigel 75 when the subpattern is first used, so, for example, (a\e1) never matches. 1563 nigel 63 However, such references can be useful inside repeated subpatterns. For 1564 example, the pattern 1565 nigel 75 .sp 1566 (a|b\e1)+ 1567 .sp 1568 nigel 63 matches any number of "a"s and also "aba", "ababbaa" etc. At each iteration of 1569 the subpattern, the back reference matches the character string corresponding 1570 to the previous iteration. In order for this to work, the pattern must be such 1571 that the first iteration does not need to match the back reference. This can be 1572 done using alternation, as in the example above, or by a quantifier with a 1573 minimum of zero. 1574 nigel 75 . 1575 . 1576 .\" HTML 1577 nigel 63 .SH ASSERTIONS 1578 .rs 1579 .sp 1580 An assertion is a test on the characters following or preceding the current 1581 matching point that does not actually consume any characters. The simple 1582 nigel 75 assertions coded as \eb, \eB, \eA, \eG, \eZ, \ez, ^ and$ are described 1583 .\" HTML 1584 .\" 1585 above. 1586 .\" 1587 .P 1588 nigel 63 More complicated assertions are coded as subpatterns. There are two kinds: 1589 those that look ahead of the current position in the subject string, and those 1590 nigel 75 that look behind it. An assertion subpattern is matched in the normal way, 1591 except that it does not cause the current matching position to be changed. 1592 .P 1593 Assertion subpatterns are not capturing subpatterns, and may not be repeated, 1594 because it makes no sense to assert the same thing several times. If any kind 1595 of assertion contains capturing subpatterns within it, these are counted for 1596 the purposes of numbering the capturing subpatterns in the whole pattern. 1597 However, substring capturing is carried out only for positive assertions, 1598 because it does not make sense for negative assertions. 1599 . 1600 . 1601 .SS "Lookahead assertions" 1602 .rs 1603 .sp 1604 nigel 91 Lookahead assertions start with (?= for positive assertions and (?! for 1605 negative assertions. For example, 1606 nigel 75 .sp 1607 \ew+(?=;) 1608 .sp 1609 nigel 63 matches a word followed by a semicolon, but does not include the semicolon in 1610 the match, and 1611 nigel 75 .sp 1612 nigel 63 foo(?!bar) 1613 nigel 75 .sp 1614 nigel 63 matches any occurrence of "foo" that is not followed by "bar". Note that the 1615 apparently similar pattern 1616 nigel 75 .sp 1617 nigel 63 (?!foo)bar 1618 nigel 75 .sp 1619 nigel 63 does not find an occurrence of "bar" that is preceded by something other than 1620 "foo"; it finds any occurrence of "bar" whatsoever, because the assertion 1621 (?!foo) is always true when the next three characters are "bar". A 1622 nigel 75 lookbehind assertion is needed to achieve the other effect. 1623 .P 1624 nigel 63 If you want to force a matching failure at some point in a pattern, the most 1625 convenient way to do it is with (?!) because an empty string always matches, so 1626 an assertion that requires there not to be an empty string must always fail. 1627 nigel 75 . 1628 . 1629 .\" HTML 1630 .SS "Lookbehind assertions" 1631 .rs 1632 .sp 1633 nigel 63 Lookbehind assertions start with (?<= for positive assertions and (? 1663 .\" 1664 (see above) 1665 .\" 1666 can be used instead of a lookbehind assertion; this is not restricted to a 1667 fixed-length. 1668 .P 1669 nigel 63 The implementation of lookbehind assertions is, for each alternative, to 1670 nigel 93 temporarily move the current position back by the fixed length and then try to 1671 nigel 63 match. If there are insufficient characters before the current position, the 1672 nigel 93 assertion fails. 1673 nigel 75 .P 1674 PCRE does not allow the \eC escape (which matches a single byte in UTF-8 mode) 1675 nigel 63 to appear in lookbehind assertions, because it makes it impossible to calculate 1676 nigel 93 the length of the lookbehind. The \eX and \eR escapes, which can match 1677 different numbers of bytes, are also not permitted. 1678 nigel 75 .P 1679 nigel 93 Possessive quantifiers can be used in conjunction with lookbehind assertions to 1680 specify efficient matching at the end of the subject string. Consider a simple 1681 pattern such as 1682 nigel 75 .sp 1683 nigel 63 abcd$1684 nigel 75 .sp 1685 nigel 63 when applied to a long string that does not match. Because matching proceeds 1686 from left to right, PCRE will look for each "a" in the subject and then see if 1687 what follows matches the rest of the pattern. If the pattern is specified as 1688 nigel 75 .sp 1689 nigel 63 ^.*abcd$ 1690 nigel 75 .sp 1691 nigel 63 the initial .* matches the entire string at first, but when this fails (because 1692 there is no following "a"), it backtracks to match all but the last character, 1693 then all but the last two characters, and so on. Once again the search for "a" 1694 covers the entire string, from right to left, so we are no better off. However, 1695 if the pattern is written as 1696 nigel 75 .sp 1697 nigel 63 ^.*+(?<=abcd) 1698 nigel 75 .sp 1699 nigel 93 there can be no backtracking for the .*+ item; it can match only the entire 1700 nigel 63 string. The subsequent lookbehind assertion does a single test on the last four 1701 characters. If it fails, the match fails immediately. For long strings, this 1702 approach makes a significant difference to the processing time. 1703 nigel 75 . 1704 . 1705 .SS "Using multiple assertions" 1706 .rs 1707 .sp 1708 nigel 63 Several assertions (of any sort) may occur in succession. For example, 1709 nigel 75 .sp 1710 (?<=\ed{3})(? 1740 nigel 75 .SH "CONDITIONAL SUBPATTERNS" 1741 nigel 63 .rs 1742 .sp 1743 It is possible to cause the matching process to obey a subpattern 1744 conditionally or to choose between two alternative subpatterns, depending on 1745 the result of an assertion, or whether a previous capturing subpattern matched 1746 or not. The two possible forms of conditional subpattern are 1747 nigel 75 .sp 1748 nigel 63 (?(condition)yes-pattern) 1749 (?(condition)yes-pattern|no-pattern) 1750 nigel 75 .sp 1751 nigel 63 If the condition is satisfied, the yes-pattern is used; otherwise the 1752 no-pattern (if present) is used. If there are more than two alternatives in the 1753 subpattern, a compile-time error occurs. 1754 nigel 75 .P 1755 nigel 93 There are four kinds of condition: references to subpatterns, references to 1756 recursion, a pseudo-condition called DEFINE, and assertions. 1757 . 1758 .SS "Checking for a used subpattern by number" 1759 .rs 1760 .sp 1761 If the text between the parentheses consists of a sequence of digits, the 1762 condition is true if the capturing subpattern of that number has previously 1763 ph10 172 matched. An alternative notation is to precede the digits with a plus or minus 1764 ph10 167 sign. In this case, the subpattern number is relative rather than absolute. 1765 ph10 172 The most recently opened parentheses can be referenced by (?(-1), the next most 1766 ph10 167 recent by (?(-2), and so on. In looping constructs it can also make sense to 1767 refer to subsequent groups with constructs such as (?(+2). 1768 nigel 91 .P 1769 Consider the following pattern, which contains non-significant white space to 1770 make it more readable (assume the PCRE_EXTENDED option) and to divide it into 1771 three parts for ease of discussion: 1772 nigel 75 .sp 1773 ( \e( )? [^()]+ (?(1) \e) ) 1774 .sp 1775 nigel 63 The first part matches an optional opening parenthesis, and if that 1776 character is present, sets it as the first captured substring. The second part 1777 matches one or more characters that are not parentheses. The third part is a 1778 conditional subpattern that tests whether the first set of parentheses matched 1779 or not. If they did, that is, if subject started with an opening parenthesis, 1780 the condition is true, and so the yes-pattern is executed and a closing 1781 parenthesis is required. Otherwise, since no-pattern is not present, the 1782 subpattern matches nothing. In other words, this pattern matches a sequence of 1783 nigel 93 non-parentheses, optionally enclosed in parentheses. 1784 ph10 167 .P 1785 ph10 172 If you were embedding this pattern in a larger one, you could use a relative 1786 ph10 167 reference: 1787 .sp 1788 ...other stuff... ( \e( )? [^()]+ (?(-1) \e) ) ... 1789 .sp 1790 This makes the fragment independent of the parentheses in the larger pattern. 1791 nigel 93 . 1792 .SS "Checking for a used subpattern by name" 1793 .rs 1794 nigel 91 .sp 1795 nigel 93 Perl uses the syntax (?()...) or (?('name')...) to test for a used 1796 subpattern by name. For compatibility with earlier versions of PCRE, which had 1797 this facility before Perl, the syntax (?(name)...) is also recognized. However, 1798 there is a possible ambiguity with this syntax, because subpattern names may 1799 consist entirely of digits. PCRE looks first for a named subpattern; if it 1800 cannot find one and the name consists entirely of digits, PCRE looks for a 1801 subpattern of that number, which must be greater than zero. Using subpattern 1802 names that consist entirely of digits is not recommended. 1803 .P 1804 Rewriting the above example to use a named subpattern gives this: 1805 nigel 91 .sp 1806 nigel 93 (? \e( )? [^()]+ (?() \e) ) 1807 .sp 1808 . 1809 .SS "Checking for pattern recursion" 1810 .rs 1811 .sp 1812 nigel 91 If the condition is the string (R), and there is no subpattern with the name R, 1813 nigel 93 the condition is true if a recursive call to the whole pattern or any 1814 subpattern has been made. If digits or a name preceded by ampersand follow the 1815 letter R, for example: 1816 .sp 1817 (?(R3)...) or (?(R&name)...) 1818 .sp 1819 the condition is true if the most recent recursion is into the subpattern whose 1820 number or name is given. This condition does not check the entire recursion 1821 stack. 1822 nigel 75 .P 1823 nigel 93 At "top level", all these recursion test conditions are false. Recursive 1824 patterns are described below. 1825 . 1826 .SS "Defining subpatterns for use by reference only" 1827 .rs 1828 .sp 1829 If the condition is the string (DEFINE), and there is no subpattern with the 1830 name DEFINE, the condition is always false. In this case, there may be only one 1831 alternative in the subpattern. It is always skipped if control reaches this 1832 point in the pattern; the idea of DEFINE is that it can be used to define 1833 "subroutines" that can be referenced from elsewhere. (The use of "subroutines" 1834 is described below.) For example, a pattern to match an IPv4 address could be 1835 written like this (ignore whitespace and line breaks): 1836 .sp 1837 (?(DEFINE) (? 2[0-4]\ed | 25[0-5] | 1\ed\ed | [1-9]?\ed) ) 1838 \eb (?&byte) (\e.(?&byte)){3} \eb 1839 .sp 1840 The first part of the pattern is a DEFINE group inside which a another group 1841 named "byte" is defined. This matches an individual component of an IPv4 1842 address (a number less than 256). When matching takes place, this part of the 1843 pattern is skipped because DEFINE acts like a false condition. 1844 .P 1845 The rest of the pattern uses references to the named group to match the four 1846 dot-separated components of an IPv4 address, insisting on a word boundary at 1847 each end. 1848 . 1849 .SS "Assertion conditions" 1850 .rs 1851 .sp 1852 If the condition is not in any of the above formats, it must be an assertion. 1853 nigel 63 This may be a positive or negative lookahead or lookbehind assertion. Consider 1854 this pattern, again containing non-significant white space, and with the two 1855 alternatives on the second line: 1856 nigel 75 .sp 1857 nigel 63 (?(?=[^a-z]*[a-z]) 1858 nigel 75 \ed{2}-[a-z]{3}-\ed{2} | \ed{2}-\ed{2}-\ed{2} ) 1859 .sp 1860 nigel 63 The condition is a positive lookahead assertion that matches an optional 1861 sequence of non-letters followed by a letter. In other words, it tests for the 1862 presence of at least one letter in the subject. If a letter is found, the 1863 subject is matched against the first alternative; otherwise it is matched 1864 against the second. This pattern matches strings in one of the two forms 1865 dd-aaa-dd or dd-dd-dd, where aaa are letters and dd are digits. 1866 nigel 75 . 1867 . 1868 .\" HTML 1869 nigel 63 .SH COMMENTS 1870 .rs 1871 .sp 1872 nigel 75 The sequence (?# marks the start of a comment that continues up to the next 1873 nigel 63 closing parenthesis. Nested parentheses are not permitted. The characters 1874 that make up a comment play no part in the pattern matching at all. 1875 nigel 75 .P 1876 nigel 63 If the PCRE_EXTENDED option is set, an unescaped # character outside a 1877 nigel 91 character class introduces a comment that continues to immediately after the 1878 next newline in the pattern. 1879 nigel 75 . 1880 . 1881 nigel 91 .\" HTML 1882 nigel 75 .SH "RECURSIVE PATTERNS" 1883 nigel 63 .rs 1884 .sp 1885 Consider the problem of matching a string in parentheses, allowing for 1886 unlimited nested parentheses. Without the use of recursion, the best that can 1887 be done is to use a pattern that matches up to some fixed depth of nesting. It 1888 nigel 93 is not possible to handle an arbitrary nesting depth. 1889 .P 1890 For some time, Perl has provided a facility that allows regular expressions to 1891 recurse (amongst other things). It does this by interpolating Perl code in the 1892 expression at run time, and the code can refer to the expression itself. A Perl 1893 pattern using code interpolation to solve the parentheses problem can be 1894 created like this: 1895 nigel 75 .sp 1896 $re = qr{\e( (?: (?>[^()]+) | (?p{$re}) )* \e)}x; 1897 .sp 1898 nigel 63 The (?p{...}) item interpolates Perl code at run time, and in this case refers 1899 nigel 93 recursively to the pattern in which it appears. 1900 nigel 75 .P 1901 nigel 93 Obviously, PCRE cannot support the interpolation of Perl code. Instead, it 1902 supports special syntax for recursion of the entire pattern, and also for 1903 individual subpattern recursion. After its introduction in PCRE and Python, 1904 this kind of recursion was introduced into Perl at release 5.10. 1905 nigel 75 .P 1906 nigel 93 A special item that consists of (? followed by a number greater than zero and a 1907 closing parenthesis is a recursive call of the subpattern of the given number, 1908 provided that it occurs inside that subpattern. (If not, it is a "subroutine" 1909 call, which is described in the next section.) The special item (?R) or (?0) is 1910 a recursive call of the entire regular expression. 1911 nigel 87 .P 1912 nigel 93 In PCRE (like Python, but unlike Perl), a recursive subpattern call is always 1913 treated as an atomic group. That is, once it has matched some of the subject 1914 string, it is never re-entered, even if it contains untried alternatives and 1915 there is a subsequent matching failure. 1916 .P 1917 nigel 87 This PCRE pattern solves the nested parentheses problem (assume the 1918 PCRE_EXTENDED option is set so that white space is ignored): 1919 nigel 75 .sp 1920 \e( ( (?>[^()]+) | (?R) )* \e) 1921 .sp 1922 nigel 63 First it matches an opening parenthesis. Then it matches any number of 1923 substrings which can either be a sequence of non-parentheses, or a recursive 1924 nigel 87 match of the pattern itself (that is, a correctly parenthesized substring). 1925 nigel 63 Finally there is a closing parenthesis. 1926 nigel 75 .P 1927 nigel 63 If this were part of a larger pattern, you would not want to recurse the entire 1928 pattern, so instead you could use this: 1929 nigel 75 .sp 1930 ( \e( ( (?>[^()]+) | (?1) )* \e) ) 1931 .sp 1932 nigel 63 We have put the pattern into parentheses, and caused the recursion to refer to 1933 ph10 172 them instead of the whole pattern. 1934 ph10 166 .P 1935 In a larger pattern, keeping track of parenthesis numbers can be tricky. This 1936 is made easier by the use of relative references. (A Perl 5.10 feature.) 1937 Instead of (?1) in the pattern above you can write (?-2) to refer to the second 1938 most recently opened parentheses preceding the recursion. In other words, a 1939 negative number counts capturing parentheses leftwards from the point at which 1940 it is encountered. 1941 .P 1942 It is also possible to refer to subsequently opened parentheses, by writing 1943 references such as (?+2). However, these cannot be recursive because the 1944 reference is not inside the parentheses that are referenced. They are always 1945 "subroutine" calls, as described in the next section. 1946 .P 1947 An alternative approach is to use named parentheses instead. The Perl syntax 1948 for this is (?&name); PCRE's earlier syntax (?P>name) is also supported. We 1949 could rewrite the above example as follows: 1950 nigel 75 .sp 1951 nigel 93 (? \e( ( (?>[^()]+) | (?&pn) )* \e) ) 1952 nigel 75 .sp 1953 nigel 93 If there is more than one subpattern with the same name, the earliest one is 1954 ph10 172 used. 1955 ph10 166 .P 1956 This particular example pattern that we have been looking at contains nested 1957 unlimited repeats, and so the use of atomic grouping for matching strings of 1958 non-parentheses is important when applying the pattern to strings that do not 1959 match. For example, when this pattern is applied to 1960 nigel 75 .sp 1961 nigel 63 (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa() 1962 nigel 75 .sp 1963 nigel 63 it yields "no match" quickly. However, if atomic grouping is not used, 1964 the match runs for a very long time indeed because there are so many different 1965 ways the + and * repeats can carve up the subject, and all have to be tested 1966 before failure can be reported. 1967 nigel 75 .P 1968 nigel 63 At the end of a match, the values set for any capturing subpatterns are those 1969 from the outermost level of the recursion at which the subpattern value is set. 1970 If you want to obtain intermediate values, a callout function can be used (see 1971 nigel 93 below and the 1972 nigel 63 .\" HREF 1973 nigel 75 \fBpcrecallout\fP 1974 nigel 63 .\" 1975 documentation). If the pattern above is matched against 1976 nigel 75 .sp 1977 nigel 63 (ab(cd)ef) 1978 nigel 75 .sp 1979 nigel 63 the value for the capturing parentheses is "ef", which is the last value taken 1980 on at the top level. If additional parentheses are added, giving 1981 nigel 75 .sp 1982 \e( ( ( (?>[^()]+) | (?R) )* ) \e) 1983 nigel 63 ^ ^ 1984 ^ ^ 1985 nigel 75 .sp 1986 nigel 63 the string they capture is "ab(cd)ef", the contents of the top level 1987 parentheses. If there are more than 15 capturing parentheses in a pattern, PCRE 1988 has to obtain extra memory to store data during a recursion, which it does by 1989 nigel 75 using \fBpcre_malloc\fP, freeing it via \fBpcre_free\fP afterwards. If no 1990 nigel 63 memory can be obtained, the match fails with the PCRE_ERROR_NOMEMORY error. 1991 nigel 75 .P 1992 nigel 63 Do not confuse the (?R) item with the condition (R), which tests for recursion. 1993 Consider this pattern, which matches text in angle brackets, allowing for 1994 arbitrary nesting. Only digits are allowed in nested brackets (that is, when 1995 recursing), whereas any characters are permitted at the outer level. 1996 nigel 75 .sp 1997 < (?: (?(R) \ed++ | [^<>]*+) | (?R)) * > 1998 .sp 1999 nigel 63 In this pattern, (?(R) is the start of a conditional subpattern, with two 2000 different alternatives for the recursive and non-recursive cases. The (?R) item 2001 is the actual recursive call. 2002 nigel 75 . 2003 . 2004 nigel 63 .\" HTML 2005 nigel 75 .SH "SUBPATTERNS AS SUBROUTINES" 2006 nigel 63 .rs 2007 .sp 2008 If the syntax for a recursive subpattern reference (either by number or by 2009 name) is used outside the parentheses to which it refers, it operates like a 2010 nigel 93 subroutine in a programming language. The "called" subpattern may be defined 2011 ph10 166 before or after the reference. A numbered reference can be absolute or 2012 relative, as in these examples: 2013 nigel 75 .sp 2014 ph10 166 (...(absolute)...)...(?2)... 2015 (...(relative)...)...(?-1)... 2016 ph10 172 (...(?+1)...(relative)... 2017 ph10 166 .sp 2018 An earlier example pointed out that the pattern 2019 .sp 2020 nigel 75 (sens|respons)e and \e1ibility 2021 .sp 2022 nigel 63 matches "sense and sensibility" and "response and responsibility", but not 2023 "sense and responsibility". If instead the pattern 2024 nigel 75 .sp 2025 nigel 63 (sens|respons)e and (?1)ibility 2026 nigel 75 .sp 2027 nigel 63 is used, it does match "sense and responsibility" as well as the other two 2028 nigel 93 strings. Another example is given in the discussion of DEFINE above. 2029 nigel 87 .P 2030 Like recursive subpatterns, a "subroutine" call is always treated as an atomic 2031 group. That is, once it has matched some of the subject string, it is never 2032 re-entered, even if it contains untried alternatives and there is a subsequent 2033 matching failure. 2034 nigel 93 .P 2035 When a subpattern is used as a subroutine, processing options such as 2036 case-independence are fixed when the subpattern is defined. They cannot be 2037 changed for different calls. For example, consider this pattern: 2038 .sp 2039 ph10 166 (abc)(?i:(?-1)) 2040 nigel 93 .sp 2041 It matches "abcabc". It does not match "abcABC" because the change of 2042 processing option does not affect the called subpattern. 2043 nigel 75 . 2044 . 2045 ph10 333 .\" HTML 2046 .SH "ONIGURUMA SUBROUTINE SYNTAX" 2047 .rs 2048 .sp 2049 For compatibility with Oniguruma, the non-Perl syntax \eg followed by a name or 2050 a number enclosed either in angle brackets or single quotes, is an alternative 2051 syntax for referencing a subpattern as a subroutine, possibly recursively. Here 2052 are two of the examples used above, rewritten using this syntax: 2053 .sp 2054 (? \e( ( (?>[^()]+) | \eg )* \e) ) 2055 (sens|respons)e and \eg'1'ibility 2056 .sp 2057 PCRE supports an extension to Oniguruma: if a number is preceded by a 2058 plus or a minus sign it is taken as a relative reference. For example: 2059 .sp 2060 (abc)(?i:\eg<-1>) 2061 .sp 2062 Note that \eg{...} (Perl syntax) and \eg<...> (Oniguruma syntax) are \fInot\fP 2063 synonymous. The former is a back reference; the latter is a subroutine call. 2064 . 2065 . 2066 nigel 63 .SH CALLOUTS 2067 .rs 2068 .sp 2069 Perl has a feature whereby using the sequence (?{...}) causes arbitrary Perl 2070 code to be obeyed in the middle of matching a regular expression. This makes it 2071 possible, amongst other things, to extract different substrings that match the 2072 same pair of parentheses when there is a repetition. 2073 nigel 75 .P 2074 nigel 63 PCRE provides a similar feature, but of course it cannot obey arbitrary Perl 2075 code. The feature is called "callout". The caller of PCRE provides an external 2076 nigel 75 function by putting its entry point in the global variable \fIpcre_callout\fP. 2077 nigel 63 By default, this variable contains NULL, which disables all calling out. 2078 nigel 75 .P 2079 nigel 63 Within a regular expression, (?C) indicates the points at which the external 2080 function is to be called. If you want to identify different callout points, you 2081 can put a number less than 256 after the letter C. The default value is zero. 2082 For example, this pattern has two callout points: 2083 nigel 75 .sp 2084 ph10 155 (?C1)abc(?C2)def 2085 nigel 75 .sp 2086 If the PCRE_AUTO_CALLOUT flag is passed to \fBpcre_compile()\fP, callouts are 2087 automatically installed before each item in the pattern. They are all numbered 2088 255. 2089 .P 2090 During matching, when PCRE reaches a callout point (and \fIpcre_callout\fP is 2091 nigel 63 set), the external function is called. It is provided with the number of the 2092 nigel 75 callout, the position in the pattern, and, optionally, one item of data 2093 originally supplied by the caller of \fBpcre_exec()\fP. The callout function 2094 may cause matching to proceed, to backtrack, or to fail altogether. A complete 2095 description of the interface to the callout function is given in the 2096 nigel 63 .\" HREF 2097 nigel 75 \fBpcrecallout\fP 2098 nigel 63 .\" 2099 documentation. 2100 nigel 93 . 2101 . 2102 ph10 235 .SH "BACKTRACKING CONTROL" 2103 ph10 210 .rs 2104 .sp 2105 ph10 211 Perl 5.10 introduced a number of "Special Backtracking Control Verbs", which 2106 ph10 210 are described in the Perl documentation as "experimental and subject to change 2107 ph10 211 or removal in a future version of Perl". It goes on to say: "Their usage in 2108 production code should be noted to avoid problems during upgrades." The same 2109 ph10 210 remarks apply to the PCRE features described in this section. 2110 .P 2111 ph10 211 Since these verbs are specifically related to backtracking, they can be used 2112 only when the pattern is to be matched using \fBpcre_exec()\fP, which uses a 2113 backtracking algorithm. They cause an error if encountered by 2114 ph10 210 \fBpcre_dfa_exec()\fP. 2115 .P 2116 ph10 211 The new verbs make use of what was previously invalid syntax: an opening 2117 ph10 210 parenthesis followed by an asterisk. In Perl, they are generally of the form 2118 (*VERB:ARG) but PCRE does not support the use of arguments, so its general 2119 form is just (*VERB). Any number of these verbs may occur in a pattern. There 2120 are two kinds: 2121 . 2122 .SS "Verbs that act immediately" 2123 .rs 2124 .sp 2125 The following verbs act as soon as they are encountered: 2126 .sp 2127 (*ACCEPT) 2128 .sp 2129 This verb causes the match to end successfully, skipping the remainder of the 2130 ph10 211 pattern. When inside a recursion, only the innermost pattern is ended 2131 immediately. PCRE differs from Perl in what happens if the (*ACCEPT) is inside 2132 ph10 210 capturing parentheses. In Perl, the data so far is captured: in PCRE no data is 2133 captured. For example: 2134 .sp 2135 A(A|B(*ACCEPT)|C)D 2136 .sp 2137 ph10 211 This matches "AB", "AAD", or "ACD", but when it matches "AB", no data is 2138 ph10 210 captured. 2139 .sp 2140 (*FAIL) or (*F) 2141 .sp 2142 ph10 211 This verb causes the match to fail, forcing backtracking to occur. It is 2143 ph10 210 equivalent to (?!) but easier to read. The Perl documentation notes that it is 2144 probably useful only when combined with (?{}) or (??{}). Those are, of course, 2145 Perl features that are not present in PCRE. The nearest equivalent is the 2146 callout feature, as for example in this pattern: 2147 .sp 2148 a+(?C)(*FAIL) 2149 .sp 2150 ph10 211 A match with the string "aaaa" always fails, but the callout is taken before 2151 each backtrack happens (in this example, 10 times). 2152 ph10 210 . 2153 .SS "Verbs that act after backtracking" 2154 .rs 2155 .sp 2156 ph10 211 The following verbs do nothing when they are encountered. Matching continues 2157 with what follows, but if there is no subsequent match, a failure is forced. 2158 ph10 210 The verbs differ in exactly what kind of failure occurs. 2159 .sp 2160 (*COMMIT) 2161 .sp 2162 ph10 211 This verb causes the whole match to fail outright if the rest of the pattern 2163 ph10 210 does not match. Even if the pattern is unanchored, no further attempts to find 2164 a match by advancing the start point take place. Once (*COMMIT) has been 2165 ph10 211 passed, \fBpcre_exec()\fP is committed to finding a match at the current 2166 ph10 210 starting point, or not at all. For example: 2167 .sp 2168 a+(*COMMIT)b 2169 .sp 2170 ph10 211 This matches "xxaab" but not "aacaab". It can be thought of as a kind of 2171 ph10 210 dynamic anchor, or "I've started, so I must finish." 2172 .sp 2173 (*PRUNE) 2174 .sp 2175 ph10 211 This verb causes the match to fail at the current position if the rest of the 2176 pattern does not match. If the pattern is unanchored, the normal "bumpalong" 2177 ph10 210 advance to the next starting character then happens. Backtracking can occur as 2178 usual to the left of (*PRUNE), or when matching to the right of (*PRUNE), but 2179 if there is no match to the right, backtracking cannot cross (*PRUNE). 2180 ph10 211 In simple cases, the use of (*PRUNE) is just an alternative to an atomic 2181 ph10 210 group or possessive quantifier, but there are some uses of (*PRUNE) that cannot 2182 be expressed in any other way. 2183 .sp 2184 (*SKIP) 2185 .sp 2186 ph10 211 This verb is like (*PRUNE), except that if the pattern is unanchored, the 2187 ph10 210 "bumpalong" advance is not to the next character, but to the position in the 2188 subject where (*SKIP) was encountered. (*SKIP) signifies that whatever text 2189 was matched leading up to it cannot be part of a successful match. Consider: 2190 .sp 2191 a+(*SKIP)b 2192 .sp 2193 ph10 211 If the subject is "aaaac...", after the first match attempt fails (starting at 2194 ph10 210 the first character in the string), the starting point skips on to start the 2195 ph10 211 next attempt at "c". Note that a possessive quantifer does not have the same 2196 ph10 210 effect in this example; although it would suppress backtracking during the 2197 first match attempt, the second attempt would start at the second character 2198 instead of skipping on to "c". 2199 .sp 2200 (*THEN) 2201 ph10 211 .sp 2202 ph10 210 This verb causes a skip to the next alternation if the rest of the pattern does 2203 not match. That is, it cancels pending backtracking, but only within the 2204 current alternation. Its name comes from the observation that it can be used 2205 for a pattern-based if-then-else block: 2206 .sp 2207 ( COND1 (*THEN) FOO | COND2 (*THEN) BAR | COND3 (*THEN) BAZ ) ... 2208 .sp 2209 ph10 211 If the COND1 pattern matches, FOO is tried (and possibly further items after 2210 ph10 210 the end of the group if FOO succeeds); on failure the matcher skips to the 2211 ph10 211 second alternative and tries COND2, without backtracking into COND1. If (*THEN) 2212 ph10 210 is used outside of any alternation, it acts exactly like (*PRUNE). 2213 . 2214 . 2215 nigel 93 .SH "SEE ALSO" 2216 .rs 2217 .sp 2218 \fBpcreapi\fP(3), \fBpcrecallout\fP(3), \fBpcrematching\fP(3), \fBpcre\fP(3). 2219 ph10 99 . 2220 . 2221 .SH AUTHOR 2222 .rs 2223 .sp 2224 .nf 2225 Philip Hazel 2226 University Computing Service 2227 Cambridge CB2 3QH, England. 2228 .fi 2229 . 2230 . 2231 .SH REVISION 2232 .rs 2233 .sp 2234 .nf 2235 ph10 333 Last updated: 10 April 2008 2236 Copyright (c) 1997-2008 University of Cambridge. 2237 ph10 99 .fi
## Properties
Name Value
svn:eol-style native
svn:keywords "Author Date Id Revision Url"
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2013-05-19 21:14:27
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http://semantic-portal.net/javascript-async-promise-api
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# Promise API
Domains:
There are 4 static methods in the Promise class. We'll quickly cover their use cases here.
## Promise.resolve
The syntax:
let promise = Promise.resolve(value);
Returns a resolved promise with the given value.
Same as:
let promise = new Promise(resolve => resolve(value));
The method is used when we already have a value, but would like to have it "wrapped" into a promise.
For instance, the loadCached function below fetches the url and remembers the result, so that future calls on the same URL return it immediately:
function loadCached(url) {
if (cache.has(url)) {
*!*
return Promise.resolve(cache.get(url)); // (*)
*/!*
}
return fetch(url)
.then(response => response.text())
.then(text => {
cache.set(url,text);
return text;
});
}
We can use loadCached(url).then(…), because the function is guaranteed to return a promise. That's the purpose Promise.resolve in the line (*): it makes sure the interface unified. We can always use .then after loadCached.
## Promise.reject
The syntax:
let promise = Promise.reject(error);
Create a rejected promise with the error.
Same as:
let promise = new Promise((resolve, reject) => reject(error));
We cover it here for completeness, rarely used in real code.
## Promise.all
The method to run many promises in parallel and wait till all of them are ready.
The syntax is:
let promise = Promise.all(iterable);
It takes an iterable object with promises, technically it can be any iterable, but usually it's an array, and returns a new promise. The new promise resolves with when all of them are settled and has an array of their results.
For instance, the Promise.all below settles after 3 seconds, and then its result is an array [1, 2, 3]:
Promise.all([
new Promise((resolve, reject) => setTimeout(() => resolve(1), 3000)), // 1
new Promise((resolve, reject) => setTimeout(() => resolve(2), 2000)), // 2
new Promise((resolve, reject) => setTimeout(() => resolve(3), 1000)) // 3
]).then(alert); // 1,2,3 when promises are ready: each promise contributes an array member
Please note that the relative order is the same. Even though the first promise takes the longest time to resolve, it is still first in the array of results.
A common trick is to map an array of job data into an array of promises, and then wrap that into Promise.all.
For instance, if we have an array of URLs, we can fetch them all like this:
let urls = [
'https://api.github.com/users/iliakan',
'https://api.github.com/users/remy',
'https://api.github.com/users/jeresig'
];
// map every url to the promise fetch(github url)
let requests = urls.map(url => fetch(url));
// Promise.all waits until all jobs are resolved
Promise.all(requests)
.then(responses => responses.forEach(
response => alert(${response.url}:${response.status})
));
A more real-life example with fetching user information for an array of github users by their names (or we could fetch an array of goods by their ids, the logic is same):
let names = ['iliakan', 'remy', 'jeresig'];
let requests = names.map(name => fetch(https://api.github.com/users/${name})); Promise.all(requests) .then(responses => { // all responses are ready, we can show HTTP status codes for(let response of responses) { alert(${response.url}: \${response.status}); // shows 200 for every url
}
return responses;
})
// map array of responses into array of response.json() to read their content
.then(responses => Promise.all(responses.map(r => r.json())))
// all JSON answers are parsed: "users" is the array of them
If any of the promises is rejected, Promise.all immediately rejects with that error.
For instance:
Promise.all([
new Promise((resolve, reject) => setTimeout(() => resolve(1), 1000)),
*!*
new Promise((resolve, reject) => setTimeout(() => reject(new Error("Whoops!")), 2000)),
*/!*
new Promise((resolve, reject) => setTimeout(() => resolve(3), 3000))
Here the second promise rejects in two seconds. That leads to immediate rejection of Promise.all, so .catch executes: the rejection error becomes the outcome of the whole Promise.all.
The important detail is that promises provide no way to "cancel" or "abort" their execution. So other promises continue to execute, and the eventually settle, but all their results are ignored.
There are ways to avoid this: we can either write additional code to clearTimeout (or otherwise cancel) the promises in case of an error, or we can make errors show up as members in the resulting array (see the task below this chapter about it).
### Promise.all(iterable) allows non-promise items in iterable
Normally, Promise.all(iterable) accepts an iterable (in most cases an array) of promises. But if any of those objects is not a promise, it's wrapped in Promise.resolve.
For instance, here the results are [1, 2, 3]:
Promise.all([
new Promise((resolve, reject) => {
setTimeout(() => resolve(1), 1000)
}),
2, // treated as Promise.resolve(2)
3 // treated as Promise.resolve(3)
So we are able to pass non-promise values to Promise.all where convenient.
## P romise.race
Similar to Promise.all takes an iterable of promises, but instead of waiting for all of them to finish -- waits for the first result (or error), and goes on with it.
The syntax is:
let promise = Promise.race(iterable);
For instance, here the result will be 1:
Promise.race([
new Promise((resolve, reject) => setTimeout(() => resolve(1), 1000)),
new Promise((resolve, reject) => setTimeout(() => reject(new Error("Whoops!")), 2000)),
new Promise((resolve, reject) => setTimeout(() => resolve(3), 3000))
So, the first result/error becomes the result of the whole Promise.race. After the first settled promise "wins the race", all further results/errors are ignored.
## Summary
There are 4 static methods of Promise class:
1. Promise.resolve(value) -- makes a resolved promise with the given value,
2. Promise.reject(error) -- makes a rejected promise with the given error,
3. Promise.all(promises) -- waits for all promises to resolve and returns an array of their results. If any of the given promises rejects, then it becomes the error of Promise.all, and all other results are ignored.
4. Promise.race(promises) -- waits for the first promise to settle, and its result/error becomes the outcome.
Of these four, Promise.all is the most common in practice.
Page structure
Terms
|
2022-11-29 01:27:07
|
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https://xmphysics.com/category/04-forces/
|
Category: 04 Forces
# 4.6.1 Why must Three Forces Intersect at the Same Point?
A video explanation of the origin of this “rule”.
A visual “proof” of this rule.
The classic “ladder against wall” problem:
# 4.6 Static Equilibrium
Here is the “proof” for the summation of moments is constant regardless of pivot point when net force is zero. This is not required by H2 syllabus. So watch it only if you’re interested.
Below are a few worked examples
# 4.5.1 Moments
Just a video explanation on how to calculate moments.
# 4.4 Translational Equilibrium
How can a 50 g mass lift a 100 g mass?
A few worked examples on translational equilibrium:
Picture Frame
Block on Slope
Submerged Buoy
# 4.3.4 Upthrust Demonstrations
Cartesian Diver
Watch me use my telekinesis power to push the diver down.
Reverse Cartesian
My telekinesis power works both ways. Impressive sia?
Double Layer Golf Ball Float
A golf ball is barely floating in brine. Cooking oil (which is less dense than brine) is going to be poured over the top. Will the golf ball sink deeper into the brine, float higher, or what?
Water See-Saw
A tub of water is originally perched precariously on a wooden peg. When a copper bob is lowered into the tub, can the see-saw hold its balance?
Water Bridge
A tub of water containing a boat is originally perched precariously on a wooden peg. When a boat embarks on a cruise around the tub, can the tub hold its balance?
# 4.3.2 Law of Floatation
• When a foreign object is submerged in a fluid, the surrounding fluid will exert pressure forces perpendicularly into each point on the surface of the foreign object.
• Because pressure increases with depth, the resultant of these pressure forces is an vertically upward force. This force is called the force of upthrust, U.
• With some simple reasoning, we can deduce that the magnitude of the upthrust must be equal to the weight of the displaced fluid. Hence
$U={{m}_{f}}g={{rho }_{f}}{{V}_{f}}g$
• To generate a larger upthrust, a body must displace more fluid.
• Similar to weight, upthrust appears to act at a single point, the centre of gravity of the displaced fluid.
• Compare the upthrust U
$U={{m}_{f}}g={{rho }_{f}}{{V}_{f}}g$
• with the weight of the object W
$W={{m}_{o}}g={{rho }_{o}}{{V}_{o}}g$
• When an object is fully submerged, Vf = Vo. This also represents the maximum upthrust the object can generate.
• If ρo > ρf , then W > Umax.
• The object will sink all the way down.
• If ρo = ρf, then W = Umax.
• The object will neither sink nor float.
• It can hover at equilibrium at any depth in the fluid as long as it is fully submerged.
• If ρo < ρf, then W < Umax.
• The object will float partially submerged.
• It will displace just enough fluid to generate the amount of upthrust exactly equal to its weight.
• The lower the object’s density, the higher it will float.
# 4.3 Upthrust
What does this video tell us about pressure vs pressure forces?
Just a video explanation.
# 4.2.1 Atmospheric Pressure
At 101 kPa, there is (0.30 x 0.30 x 101,000) = 9090 N, or about 900 kg worth of weight pressing down on the 30 cm by 30 cm pad. Because there is about 900 kg of air sitting on top of the pad!
But of course, we can’t expect the pad to lift 900 kg. Two reasons: (1) It is NOT a total vacuum under the pad. So the net downward force would be much less. (2) The pad itself (the rubber, handle knob, etc) would have been pulled apart long before that.
# 4.2 Hydrostatic Pressure
Fluids have amazing properties. Nobody says it better than Bruce Lee.
Can you explain why the water stops leaking once the bottle is dropped?
In the following video, the pig is touring the ocean in an air shaft. When is the pig in danger, when it is near the bottom or near the surface?
# 4.1.3.1 Centre of Mass and Centre of Gravity
In this video, you can see a rigid body, formed by joining two balls, being thrown across the screen. Tracing the trajectory of either ball shows a complicated path. On the other hand, the trajectory of the CM is the familiar parabolic arc of a projectile motion. What does this tell us? When analysing the translational motion of a rigid body, we should can the entire mass of the body to be concentrated at its CM.
We can also assume that the entire weight of a rigid body acts at its CG. For this toy bird, weights cleverly positioned in the tips of the wings positions the CG of the bird just BELOW its beak. With the CG below the pivot, this bird is basically a pendulum.
|
2021-11-28 22:57:54
|
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https://math.stackexchange.com/questions/1854873/showing-following-fourier-series-converges-to-sawtooth-function
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# Showing Following Fourier series converges to sawtooth function
This question is originated from S/S Fourier Analysis Chapter 2 Exercise 8.
Problem says show sawtooth function$$f(x)= \begin{cases} -\frac{\pi}{2}-\frac{x}{2}, -\pi<x<0\\ \frac{\pi}{2}-\frac{x}{2}, 0<x<\pi\\ \end{cases}$$ has fourier series $$\frac{1}{2i}\sum_{n\neq 0} \frac{e^{inx}}{n}$$
It's just a simple calculation and we can show the series converges by Dirichlet's test.
But what about the converse, $$\frac{1}{2i}\sum_{n\neq 0} \frac{e^{inx}}{n}$$ (pointwise) converges to $$f(x)= \begin{cases} -\frac{\pi}{2}-\frac{x}{2}, -\pi<x<0\\ \frac{\pi}{2}-\frac{x}{2}, 0<x<\pi\\ \end{cases}$$
For me, with only tools learned until Chapter 2, I think the only way to showing is using uniqueness of the Fourier series with uniform convergence condition.
I think the series $$\frac{1}{2i}\sum_{n\neq 0} \frac{e^{inx}}{n}$$ will uniformly convergent on $[\pi+\delta,-\delta]$ and $[\delta,\pi-\delta]$
then we can show the series has same fourier series by interchanging sum and integral and it's done. But Weierstrass M-test fails on this series.
Is the conjecture true? Otherwise, What's the another way to showing convergence to sawtooth function?
• See Wikipedia for some results on pointwise convergence of Fourier series. – Jyrki Lahtonen Jul 10 '16 at 10:45
• @JyrkiLahtonen This question is asking about not convergence itself but convergence with specific value. Also Convergence can be checked by Dirichlet's test. Can you explain why that theorem can answer the question? – Maddy Jul 11 '16 at 7:20
• The most basic result (the only one I ever learned) says that when a periodic function has one-sided limits and derivatives at a given point, the Fourier series will, at that point, converge to the average of the one-sided limits of the function. This is mentioned in the Wikipage, but admittedly the authors of that article aim a bit higher :-). Anyway, sawtooth has one-sided limits and derivatives everywhere, so it applies. – Jyrki Lahtonen Jul 11 '16 at 7:24
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2019-09-18 12:02:06
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https://pypi.org/project/arabic-reshaper/2.1.3/
|
Reconstruct Arabic sentences to be used in applications that don't support Arabic
## Python Arabic Reshaper
Reconstruct Arabic sentences to be used in applications that don't support Arabic script.
Works with Python 2.x and 3.x
## Description
Arabic script is very special with two essential features:
1. It is written from right to left.
2. The characters change shape according to their surrounding characters.
So when you try to print text written in Arabic script in an application – or a library – that doesn’t support Arabic you’re pretty likely to end up with something that looks like this:
We have two problems here, first, the characters are in the isolated form, which means that every character is rendered regardless of its surroundings, and second is that the text is written from left to right.
To solve the latter issue all we have to do is to use the Unicode bidirectional algorithm, which is implemented purely in Python in python-bidi. If you use it you’ll end up with something that looks like this:
The only issue left to solve is to reshape those characters and replace them with their correct shapes according to their surroundings. Using this library helps with the reshaping so we can get the proper result like this:
## Installation
pip install --upgrade arabic-reshaper
If you're using Anaconda you can use
conda install -c mpcabd arabic-reshaper
## Usage
import arabic_reshaper
text_to_be_reshaped = 'اللغة العربية رائعة'
reshaped_text = arabic_reshaper.reshape(text_to_be_reshaped)
### Example using PIL Image
PIL Image does not support reshaping out of the box, so to draw Arabic text on an Image instance you would need to reshape the text for sure.
For this example to work you need to run pip install --upgrade arabic-reshaper python-bidi pillow
import arabic_reshaper
text_to_be_reshaped = 'اللغة العربية رائعة'
reshaped_text = arabic_reshaper.reshape(text_to_be_reshaped)
# At this stage the text is reshaped, all letters are in their correct form
# based on their surroundings, but if you are going to print the text in a
# left-to-right context, which usually happens in libraries/apps that do not
# support Arabic and/or right-to-left text rendering, then you need to use
# get_display from python-bidi.
# Note that this is optional and depends on your usage of the reshaped text.
from bidi.algorithm import get_display
bidi_text = get_display(reshaped_text)
# At this stage the text in bidi_text can be easily rendered in any library
# that doesn't support Arabic and/or right-to-left, so use it as you'd use
# any other string. For example if you're using PIL.ImageDraw.text to draw
# text over an image you'd just use it like this...
from PIL import Image, ImageDraw, ImageFont
# We load Arial since it's a well known font that supports Arabic Unicode
font = ImageFont.truetype('Arial', 40)
image = Image.new('RGBA', (800, 600), (255,255,255,0))
image_draw = ImageDraw.Draw(image)
image_draw.text((10,10), bidi_text, fill=(255,255,255,128), font=font)
# Now the text is rendered properly on the image, you can save it to a file or just call show to see it working
image.show()
# For more details on PIL.Image and PIL.ImageDraw check the documentation
## Settings
You can configure the reshaper to your preferences, it has the following settings defined:
• language (Default: 'Arabic'): Ignored, the reshaper works with Arabic, Farsi, and Urdu, and most probably all other languages that use Arabic script.
• support_ligatures (Default: True): When this is set to False, the reshaper will not replace any ligatures, otherwise it will replace enabled ligatures.
• delete_harakat (Default: True): When this is set to False the reshaper will not delete the harakat from the text, this will result in them showing up in the reshaped text, you should enable this option if you are going to pass the reshaped text to bidi.algorithm.get_display because it will reverse the text and you'd end up with harakat applied to the next letter instead of the previous letter.
• delete_tatweel (Default False): When this is set to True the reshaper will delete the Tatweel character (U+0640) from the text before reshaping, this can be useful when you want to support ligatures and don't care about Tatweel getting deleted.
• shift_harakat_position (Default False): Whether to shift the Harakat (Tashkeel) one position so they appear correctly when string is reversed, this might solve the problem of Tashkeel in some systems, although for PIL.Image for example, this is not needed.
• support_zwj (Default True): Whether to support ZWJ (U+200D) or not.
• use_unshaped_instead_of_isolated (Default False): Use unshaped form instead of isolated form, useful in some fonts that are missing the isolated form of letters.
Besides the settings above, you can enable/disable supported ligatures. For a full list of supported ligatures and their default status check the file default-config.ini.
There are multiple ways that you can configure the reshaper in, choose the one that suits your deployment:
### Via ArabicReshaper instance configuration
Instead of directly using arabic_reshaper.reshape function, define an instance of arabic_reshaper.ArabicReshaper, and pass your config dictionary to its constructor's configuration parameter like this:
from arabic_reshaper import ArabicReshaper
configuration = {
'delete_harakat': False,
'support_ligatures': True,
'RIAL SIGN': True, # Replace ر ي ا ل with ﷼
}
reshaper = ArabicReshaper(configuration=configuration)
text_to_be_reshaped = 'سعر المنتج ١٥٠ ر' + 'يال' # had to split the string for display
reshaped_text = reshaper.reshape(text_to_be_reshaped)
### Via ArabicReshaper instance configuration_file
You can separte the configuration from your code, by copying the file default-config.ini and change its settings, then save it somewhere in your project, and then you can tell the reshaper to use your new config file, just pass the path to your config file to its constructor's configuration_file parameter like this:
from arabic_reshaper import ArabicReshaper
reshaper = ArabicReshaper(configuration_file='/path/to/your/config.ini')
text_to_be_reshaped = 'سعر المنتج ١٥٠ ر' + 'يال' # had to split the string for display
reshaped_text = reshaper.reshape(text_to_be_reshaped)
Where in you config.ini you can have something like this:
[ArabicReshaper]
delete_harakat = no
support_ligatures = yes
RIAL SIGN = yes
### Via PYTHON_ARABIC_RESHAPER_CONFIGURATION_FILE environment variable
Instead of having to rewrite your old code to configure it like above, you can define an environment variable with the name PYTHON_ARABIC_RESHAPER_CONFIGURATION_FILE and in its value put the full path to the configuration file. This way the reshape function will pick it automatically, and you won't have to change your old code.
## Settings based on a TrueType® font
If you intend to render the text in a TrueType® font, you can tell the library to generate its configuration by reading the font file to figure out what's supported in the font and what's not.
To use this feature you need to install the library with an extra option (not necessary when you install it with conda):
pip install --upgrade arabic-reshaper[with-fonttools]
Then you can use the reshaper like this:
import arabic_reshaper
reshaper = arabic_reshaper.ArabicReshaper(
arabic_reshaper.config_for_true_type_font(
'/path/to/true-type-font.ttf',
arabic_reshaper.ENABLE_ALL_LIGATURES
)
)
This will parse the font file, and figure out what ligatures it supports and enable them, as well as whether it has isolated forms or use_unshaped_instead_of_isolated should be enabled.
The second parameter to config_for_true_type_font can be one of
• ENABLE_NO_LIGATURES
• ENABLE_SENTENCES_LIGATURES
• ENABLE_WORDS_LIGATURES
• ENABLE_LETTERS_LIGATURES
• ENABLE_ALL_LIGATURES (default)
which controls what ligatures to look for, depending on your usage, see default-config.ini to know what ligatures are there.
## Tashkeel/Harakat issue
Harakat or Tashkeel might not show up properly in their correct place, depending on the application or the library that is doing the rendering for you, so you might want to enable the shift_harakat_position option if you face this problem.
## Demo
Online Arabic Reshaper: http://pydj.mpcabd.xyz/arabic-reshaper/
https://github.com/mpcabd/python-arabic-reshaper/tarball/master
## Version History
### 2.1.3
• Remove dependency on __version__.py and default-config.ini files, as they were causing problems for people who package their apps using pyinstaller or buildozer.
### 2.1.1
• Fix a warning. See #57. Thanks @fbernhart
### 2.1.0
• Added support for settings based on a TrueType® font
### 2.0.14
• New option use_unshaped_instead_of_isolated to get around some fonts missing the isolated form for letters.
### 2.0.13
BROKEN please make sure not to use this version.
### 2.0.12
• Updated letters and ligatures
• New option shift_harakat_position to try to get around the Tashkeel problem
### 2.0.11
• Proper support for ZWJ
### 2.0.10
• Fix Shadda ligatures
### 2.0.9
• Added support for ZWJ (Zero-width Joiner) (U+200D)
### 2.0.8
• Added delete_tatweel
• Added more test cases
### 2.0.7
• Fix tests for Python 2.7
### 2.0.6
• Fixed a bug with Harakat breaking the reshaping
• Wrote two small unit tests, more to come
• Moved letters and ligatures to separate files for readability/maintainability
• Moved package to its own folder for readability/maintainability
### 2.0.5
Fix error message formatting
### 2.0.4
Fix error message formatting
### 2.0.3
Use Exception instead of Error.
### 2.0.2
Use pkg_resources.resource_filename instead of depending on __file__ to access default-config.ini.
### 2.0.1
Include default-config.ini in setup.py
### 2.0.0
• Totally rewrote the code;
• Faster and better performance;
• Added the ability to configure and customise the reshaper.
### 1.0.1
• New glyphs for Farsi;
• Bugfixes.
## Contact
Abdullah Diab (mpcabd) Email: mpcabd@gmail.com Blog: http://mpcabd.xyz
For more info visit my blog post here
## Release history Release notifications | RSS feed
### Source Distribution
arabic_reshaper-2.1.3.tar.gz (24.5 kB view hashes)
Uploaded source
### Built Distributions
arabic_reshaper-2.1.3-py3-none-any.whl (20.5 kB view hashes)
Uploaded py3
arabic_reshaper-2.1.3-py2-none-any.whl (20.5 kB view hashes)
Uploaded py2
|
2022-10-04 00:51:52
|
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|
http://math.chapman.edu/~jipsen/structures/doku.php/unique_factorization_domains
|
## Unique Factorization Domains
Abbreviation: UFDom
### Definition
A unique factorization domain is an integral domains $D$ such that
every element is a product of irreducibles: $\forall a\in D \exists p_1,...,p_r\in D, n_1,...,n_r\in \mathbb{N}$ such that $a=p_1^{n_1}\cdotp_2^{n_2}...p_r^{n_r}$ and $p_i$ is irreducible for $i=1,\ldots,r$
the product is unique up to associates: $\forall \mbox{ irreducibles } p_i,q_j$ if $a=p_1^{n_1}\cdot p_2^{n_2}...p_r^{n_r}=q_1^{m_1}\cdot q_2^{m_2}...q_s^{m_s}$ then $r=s$ and each $p_i$ is an associate of some $q_j$
### Examples
Example 1: $\mathbb{Z}[x]$, the ring of polynomials with integer coefficients.
### Properties
Classtype second-order
### Finite members
$\begin{array}{lr} f(1)= &1\\ f(2)= &1\\ f(3)= &1\\ f(4)= &1\\ f(5)= &1\\ f(6)= &0\\ \end{array}$
|
2017-09-23 03:50:21
|
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|
https://advances.sciencemag.org/highwire/markup/206597/expansion?width=1000&height=500&iframe=true&postprocessors=highwire_figures%2Chighwire_math%2Chighwire_embed
|
Table 2 Performance statistics for a family of feedforward networks set up as a simple sequence of fully connected layers of the same width as the input vector.
A schematic of the network topology is given in the top diagram of Fig. 3.
Task Network Mean relative error Relative error SD Iteration time*, Tesla K40 (s) Distance distribution recovery In-(256)2-Out 0.090 0.231 0.32 In-(256)3-Out 0.077 0.208 0.44 In-(256)4-Out 0.070 0.195 0.74 In-(256)5-Out 0.069 0.194 0.99 In-(256)6-Out 0.069 0.192 1.19 Form factor recovery In-(256)2-Out 0.0065 0.0143 0.31 In-(256)3-Out 0.0042 0.0094 0.51 In-(256)4-Out 0.0037 0.0084 0.75 In-(256)5-Out 0.0034 0.0080 0.98 In-(256)6-Out 0.0034 0.0080 1.18
*Using a database with 100,000 DEER traces generated as described under “Training database generation” section.
|
2021-01-21 08:18:33
|
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|
http://gunnarpeipman.com/2016/08/asp-net-mvc-precompiling-views/
|
ASP.NET MVC: Precompiling views
This blog post is about how to really precompile ASP.NET MVC views. It destroys the myth about MvcBuildViews as precompilation tool and shows you how to configure precompiling. It also stops on some internals of precompiling and explains what are the options and limitations with it. There is also real-life example for Azure where precompiling of views may avoid some serious headaches that one may face otherwise.
What is MvcBuildViews?
MvcBuildViews is often mistakenly considered as something that when activated results in precompiled views. It doesn’t, actually. It is just a thing to include views to build process but it doesn’t compile these to project binaries folder. MvcBuildViews builds views temporarily and gives build results back to building process. If there were errors then build fails and errors are shown in Visual Studio errors window.
You can find out more about MvcBuildViews from Jim Lamb blog post Turn on Compile-time View Checking for ASP.NET MVC Projects in TFS Build 2010.
How to precompile views?
As precompiling is kind of expensive and time consuming process you really want to do it when publishing application to test or live environment. Simplest way to do it is using web site publishing. Publishing configuration has settings page where you can turn on compiling of views.
If you publish your web application then you will discover that only global.asax has something precompiled for it. But there is nothing for views.
By default it is expected that there can be updates to views and it is possible only if views are not compiled to assembly. As soon as there is assembly for views modifications to view files are not automatically reflected in application output.
Let’s open advanced settings and turn off updates to views. As ASP.NET compiler creates separate assembly for every view it’s possible we get big number of very small assemblies if there are many views. It’s possible to specify the name of assembly where all those small view assemblies are merged.
Now you are good to go with precompiled views when publishing your application.
NB! Although it may seem like good idea to have precompiled views available also on dev boxes, I suggest you to abandon this idea. Precompiling takes time more than developers want to wait and it slows down their progress as after every build they must wait until precompiling is done.
NB! If you precompile views then views are not updatable anymore. It means that if you change view file on server you don’t see any changes in output. This is because precompiled views are called from DLL-file. You have to publish your application again if you made changes to views.
Precompiled views after publishing
After publishing precompiled views can be found from bin folder of web application. In my case there is AppCode.dll file that contains code for all precompiled views. But besides this there are also files with .compiled extension. These files tell ASP.NET where is output of given view.
In my case there’s file _smsdialog.cshtml.49841770.compiled in bin folder. Here is the content of this file.
<?xml version=1.0 encoding=utf-8?>
<preserve resultType=2 virtualPath=/Views/Dialogs/_SmsDialog.cshtml
hash=ffffffffda035ab6 filehash=166a10c1bc59 flags=110000
assembly=AppCode type=ASP._Page_Views_Dialogs__SmsDialog_cshtml>
<filedeps>
<filedep name=/Views/Dialogs/_SmsDialog.cshtml />
</filedeps>
</preserve>
It defines file dependency and specifies where is the code for this view (assembly and type attributes of preserve node).
If I open AppCode.dll with decompiler I can see the source code of precompiled view.
As precompiling is done by ASP.NET command-line utilities you can also use precompiling on your build server.
Precompiled views on Azure
I worked on application that has some complex views. Compiling this views on runtime is slow even on dev box wit fast hard disc. It turned out to be times slower on Azure compute instance where web application is hosted. I investigated virtual machine that runs compute role and made the following discoveries:
• regular discs on Azure are very slow,
• compared to similar discs available they beat them only with one thing: the energy consumption,
• SSD-s are way more expensive on Azure that regular discs,
• the less disc I/O application generated the faster it is.
This is ideal case for precompiling the views. It’s not possible to avoid those .compiled files but getting all code for views to one assembly makes application startup faster because there’s only one library to load. With precompiled views your application works way faster after deployment because ASP.NET doesn’t have to build and compile views to compute role hard disc.
Wrapping up
The main take-away of this post is: MvcBuildViews is here to make building of views as part of web application building process. It doesn’t generate any output to binaries folder. Views are precompiled during publishing process and precompiling happens only if views are not expected to be modified. It is possible to configure how precompilation is done. This way it is possible to merge binaries of precompiled views to one assembly. This way it is possible to shorten the time it takes for application to start. As it turns out then precompiled views are good choice for web applications that run on Azure as it avoids some really slow disc I/O and web application gets highly responsive way faster than otherwise.
14 thoughts on “ASP.NET MVC: Precompiling views”
• Mike J says:
Informative. Dispelled a lot of myths about pre-compilation. Do yiu have any tips for improving the peofdmance of the aspnet_compiler during publishing. In my project this step takes almost 1 hour and it’s not uncommon from what I understand.
• Gunnar says:
I suggest you to check you dev box disc performance. Visual Studio and ASP.NET web tools may cause massive disc I/O when building, compiling or generating things. If disc is the bottle neck then switch over to SSD.
• Ryan Heath says:
Have you every encounter a failure on Azure with precompiled views?
It worked on the dev machine but when deployed on the azure server it would not run.
I had but could not solve it and went back to deployment without precompiled views …
// Ryan
> As precompiling is done by ASP.NET command-line utilities you can also use precompiling on your build server.
Do you have examples of those command line utilities?
When I try your steps I get some failures because the post-compiler does not recognize C# 6 features (specifically string interpolation).
Thanks for the post, this is something I’ve been wanting to nail down for a long time!
*Update* on the C# 6 syntax not recognized error: I changed my web.config to “Content” Build Action (previously it was None) and in doing so, the web.config file was copied to the obj\Release\AspnetCompileMerge\Source directory. Now the C# 6 syntax is recognized.
It is worth noting that I have the following tag changes from this stackoverflow answer: http://stackoverflow.com/questions/31548699/how-to-use-c-sharp-6-with-web-site-project-type#answer-31548773
• Gunnar says:
Ryan, I have used precompiled views only on compute instances as most of my Azure customers use these due to need for more control over VM-s where applications run. With compute instances we have had no problems this far.
• Thanks for this great post.
Any chance you call tell me how to precompile views via msbuild? You mention the commandline tools. I’m using Team Services for building and deploying the application. So I’m hoping for something a little easier.
Maybe I’ll have to switch to ‘web deploy’ in the Azure RM step. And set some parameters that way. I already used Visual Studio to create a pubxml file. Will probably look into that tomorrow. https://github.com/Microsoft/vsts-tasks/blob/master/Tasks/AzureRmWebAppDeployment/README.md
• I found the solution. Can be done with msbuild parameters, nothing special. Wrote a blog post about it and added a callback to this post. Thanks again for pointing me in the right direction.
http://blog.deltacode.be/2017/01/08/fix-slow-startup-of-asp-net-mvc-5-on-azure-app-services/
• Firas Rashid says:
You mentioned precompile views in Azure but you didn’t explain how. This cannot be done using the standard publishing tool under Visual Studio.
• Gunnar says:
Firas, it is standard publish dialog of Visual Studio and view compilation settings apply no matter where you publish your application – be it Azure or some other target environment like file system.
On Azure we really need it because just in time compilation of views can be very slow due to slow disks that are cheaper than SSD-s.
• Firas Rashid says:
Thanks Gunnar. This option is not supported if you are deploying ASP.NET MVC project to web role. I read a lot about it and eventually the tool doesn’t support it.
If this is something you believe it exists there, I would appreciate it if you can share with me the steps to do it.
• Gunnar says:
If VS deploys web role different from what regular web application publishing does then you can use dirty trick like described here: http://gunnarpeipman.com/2011/12/deploying-independent-web-applications-to-windows-azure-using-single-web-role/ This way you get all files to package that are created during usual web application publishing.
Actually the compiling of views is command that is given to MSBuild during publishing. You can also write DOS or PowerShell script for site deployment and call MSBuild there with correct parameters.
Publishing with built views works also well for Azure app services (previous web sites service). I can confirm it.
• This is a great article. So simple and a MASSIVE increase in performance of my Azure hosted Web site. Prior to this I was seriously thinking of moving to a different platfrom.
• Gunnar says:
Building of views is slow and if it happens in server then also the first request is very slow. In case of Azure web sites consider also slow disks that are okay for web because once application is loaded it doesn’t make any remarkable disk I/O.
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2017-07-22 04:43:04
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http://enymedia.com/no-bounding/cannot-determine-size-of-graphic-in-png-latex.php
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Home > No Bounding > Cannot Determine Size Of Graphic In Png Latex
# Cannot Determine Size Of Graphic In Png Latex
## Contents
I have also tried using the option \usepackage[pdftex]{graphicx} but this doesn't help. Not the answer you're looking for? Does the "bat wing" aircraft paint design have a proper name? So remove it. \documentclass[sts]{imsart} In general dvips, pdftex or xetex should not be used even with packages that know them, such as graphicx hyperref geometry that can deduce the needed driver More about the author
How do I change thickness and color of \hline on a table simultaneously؟ Primenary Strings This is my pillow Yet another electrical box fill question In vino (est?) veritas Advisor professor In Latex EPS is best, PDF is a close second. –David Z Apr 8 '09 at 21:46 1 @David: EPS and PDF are essentially equivalent when it comes to image Whereas a PDF includes DPI and size, a JPEG has only a size in terms of pixels. ( I know this is not the answer you wanted, but it's probably better If so, that's great, and we'll probably close this question as a duplicate just to keep the place tidy and to help people find answers quickly.
## Latex No Bounding Box Pdf
How to deal with a coworker that writes software to give him job security instead of solving problems? Recreate all formats. l.10 ...graphics[width=140mm]{xfig/ch1/doubsq.pdf} With \usepackage{graphics} I get the error: Runaway argument? If not, please edit your question here to explain why so that people can better focus their attention to help you. –Martin Schröder Jan 22 '13 at 15:54 add a comment|
1. I have followed suggestions I found in the archives and done the following: 1.
2. Actual meaning of 'After all' pgfmathparse basic usage Tank-Fighting Alien How to take sharper images indoors, scene with all objects in focus?
3. more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed
4. requirements in the Department of Mathematics at the University of Arizona.
Requirement Guide [pdftex] \includegraphics doesn't work (no BoundingBox) Mark Phillips mark at infoeng.flinders.edu.au Thu Mar 22 13:38:21 CET 2001 Previous message: [pdftex] pdf file not displaying properly in browser Next message: share|improve this answer edited Jan 22 '13 at 15:27 answered Jan 22 '13 at 15:17 David Carlisle 352k288401468 add a comment| up vote 2 down vote If you use the AucTeX-mode Hot Network Questions Meaning of double bracket "[[foo()]] type name;" syntax in c++? ! Latex Error: Option Clash For Package Graphicx. width=140mm]{xfig/ch1/doubsq.pdf} \end {center} !
The following one worked for me: \usepackage[dvipdfmx]{graphicx} \usepackage{bmpsize} –zeroos May 12 '15 at 20:56 Just to add: specificying natwidth and natheight also solved a problem I had with jpgs If I don't specify the them in the latex file, \includegraphics[]{../../results2/html/zerooneloss_stumps.jpg} I still get the same no BoundingBox error. Incidentally, you can change this in TexShop from the "Typeset" menu. Done: \begin{center} \includegraphics[width=140mm]{xfig/ch1/doubsq.pdf} \end{center} in my document. 4.
In it, you'll get: The week's top questions and answers Important community announcements Questions that need answers see an example newsletter Related 29Error including image in Latex15Including full LaTeX documents within Latex Error File Dvipdfm Def Not Found How can I trust that this is Google? latex jpeg pdflatex share|improve this question edited Mar 20 '10 at 14:00 asked Mar 20 '10 at 13:32 Tim 19.3k77184282 closed as off-topic by Dave Jarvis, joran, Fraser, torazaburo, Michael Mior What are 'hacker fares' at a flight search-engine?
## No Bounding Box Error In Latex
latex cannot determine the natural dimensions of an image. http://stackoverflow.com/questions/731933/error-including-image-in-latex LaTeX Error: Cannot determine size of graphic in Pictures/logo.png (no BoundingBox)1Cannot determine the size of graphic1Error of “cannot determine size of graphics”1Latex \includegraphics error: Cannot determine size of graphic in bleh.jpg Latex No Bounding Box Pdf And then recreate the formats again. (This can change the language and format settings, you can reset them in miktex->settings). –Ulrike Fischer Feb 18 '13 at 14:30 1 @m0nk3y: I Natwidth Latex If yes, a possible solution may be adding the extension to the filename title. –Marc van Dongen Feb 18 '13 at 6:23 3 @m0nk3y: There was an update some days
Thanks, Mark. -- _/~~~~~~~~\___/~~~~~~\____________________________________________________ ____/~~\_____/~~\__/~~\__________________________Mark_Phillips____________ ____/~~\_____/~~\________________________________mark at ist.flinders.edu.au_ ____/~~\HE___/~~\__/~~\APTAIN_____________________________________________ ____/~~\______/~~~~~~\____________________________________________________ __________________________________________________________________________ "They told me I was gullible ... my review here What is the total sum of the cardinalities of all subsets of a set? Word or phrase for "using excessive amount of technology to solve a low-tech task" How did early mathematicians make it without Set theory? I use pdfLaTeX in TeXworks. Latex No Bounding Box Jpg
The software package ImageMagick is used in this case to convert the images from one form to another. No need to spend time to manually set the bounding box with the time-consuming trial-and-errors method (what I did until this day). –user41288 Nov 19 '13 at 15:17 I Is it unethical to poorly translate an exam from Dutch to English and then present it to the English speaking students? click site This question is very similar to MikTex error for PNG images when trying to produce DVI and Cannot determine size of graphic.
Wien's oscillator - amplitude stabilization with Zeners (loop's gain) How are the functions used in cryptographic hash functions chosen? Convert Png To Eps How to deal with a coworker that writes software to give him job security instead of solving problems? To produce a pdf: pdflatex source.tex, where source.tex is your main file (the one that contains your preamble) –Lionel MANSUY Jan 22 '13 at 15:10 Welcome to TeX.sx!
## Teenage daughter refusing to go to school I just started my first real job, and have been asked to organize the office party.
Storage of a material that passes through non-living matter Figuring out why I'm going over hard-drive quota Word or phrase for "using excessive amount of technology to solve a low-tech task" This is all is needed. –egreg Jul 17 '13 at 13:58 | show 3 more comments 2 Answers 2 active oldest votes up vote 16 down vote accepted Options to \documentclass What is a unifier? Pdf To Eps Mac The system returned: (22) Invalid argument The remote host or network may be down.
Why is using let inside a for loop so slow on Chrome? How do I convert to PDF format ? more hot questions lang-tex about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation Science Other http://enymedia.com/no-bounding/cannot-determine-size-of-graphic-in-latex-eps.php How to deal with a coworker that writes software to give him job security instead of solving problems?
Simply paste the $$\mathrm{\LaTeX}$$ style files (and the two .png files) into the same directory as your Beamer .tex file and add \usetheme{UofA} (or \usetheme{TTU}) before your \begin{document}. It probably has to do with what compiler you are using. what was I going to say again? Can a player on a PC play with a a player on a laptop?
Type H for immediate help. ... graphics pdftex miktex png share|improve this question edited Feb 19 '13 at 10:03 Martin Schröder 11.2k43196 asked Feb 18 '13 at 4:58 m0nk3y 66118 2 Welcome to TeX.sx! Tax Free when leaving EU through the different country Do students wear muggle clothing while not in classes at Hogwarts (like they do in the films)? Is this different than pdflatex? –zkurtz Jul 17 '13 at 13:11 @dustin, no, [demo] is not there ... –zkurtz Jul 17 '13 at 13:12 1 Can you post
Hope this helps. I converted the first image to PDF and the compilation happened perfectly. And I really don't need more reputation, do I? ;-) –egreg Jul 17 '13 at 14:20 Using Texlipse under Project/Properties/Latex Project Properties output format pdf and build commands pdflatex A lot of the ACM journals and conferences actually take word files, which is even worse. –Uri Apr 8 '09 at 22:01 | show 7 more comments up vote 25 down
LaTeX Error: Cannot determine size of graphic in xfig/ch1/doubsq.pdf (no Boun dingBox).
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2018-05-28 09:34:08
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https://math.stackexchange.com/questions/2383023/index-of-a-subgroup
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# Index of a subgroup
Let $G$ be a finite group and $H$ be a subgroup of $G$. Let $q$ be a fixed prime. Suppose that for every Sylow subgroup $P$ of $G$, the index of $H$ in $H^P$ is a power of $q$. What can we say about $|H^G:H|$?
1. $H^X=\langle x^{-1} Hx |x\in X\rangle$
2. I guess that $|H^G:H|$ is also a power of $q$.
3. I can easily prove $|H^G: H|$ is a power of $q$ when $H$ is a subnormal subgroup of $G$.
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2019-05-23 10:58:23
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https://codereview.stackexchange.com/questions/159417/anagram-substrings-in-a-string
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# Anagram substrings in a string
I was trying to solve this questions:
Given an input string, find all combination of unique substrings, which are anagrams of each other and distinct from each other. The substrings must follow 2 <= length(substring) < len(original string).
Example 1:
• String: “vadapav”
• substrings: va, vad, vada, vadap, vadapa, ad, ada, adap, adapa, adapav, da, dap, dapa, dapav, ap, apa, apav, pa, pav, av
• Output: (va, av), (ad, da), (ap, pa)
How can it be optimised in terms of algorithmic and code complexity?
# Code goes below
from collections import defaultdict
import itertools
def anagram_substring(str):
substr_list = []
ans = []
is_present = defaultdict(list)
for i in xrange(len(str)):
for j in xrange(i+2, len(str)+1):
substr_list.append(str[i:j])
substr_list = list(set(substr_list))
for substr in substr_list:
if is_present[''.join(sorted(substr))]:
for anagram_str in is_present[''.join(sorted(substr))]:
ans.append([anagram_str,substr])
is_present[''.join(sorted(substr))].append(substr)
return ans
str = raw_input().strip()
print anagram_substring(str)
• The requirement 'The substrings must follow 2 <= length(substring) < len(original string)' is supefluous, because it follows from the preceding sentence: 1-char anagrams can't be distinct, hence len>1, and there's only one substring with length equal to the input string, so it couldn't differ from itself, either. – CiaPan Mar 31 '17 at 8:46
• If you do not have all expected outputs, the code is broken, which is off-topic here, but my suggestion would be to at least remove duplicates with a set when building the list. – ChatterOne Mar 31 '17 at 8:50
• As far as I can understand your code, you test for two substrings for being reverse of one another (like "dome" & "emod"), not anagrams (like "dome" & "mode"). Reverse is a special case of anagram, but not every anagram is a reverse; not if string has more than 2 characters. For example, in "brabant" your code could find "ab" & "ba", but probably not "bra" & "rab". – CiaPan Mar 31 '17 at 8:56
• IMHO from the problem description it follows that for "barbarian" the solution should be similar to ("bar", "arb", "bra"). Can your code produce that? – CiaPan Mar 31 '17 at 9:05
• yes, I modified code, its working fine, can it be optimised more? – Harsha Mar 31 '17 at 12:57
There's no need to use a list and convert it to a set, you can use a set from the start.
Also, you're checking for every entry if it's in the list as an anagram and adding it to the answer, which is inefficient. You can do this in a faster way by using a dictionary that has the sorted substr as key and pushing the values in there.
from collections import defaultdict
import itertools
def anagram_substring(str):
substr_list = set([])
anagrams = defaultdict(list)
for i in xrange(len(str)):
for j in xrange(i + 2, len(str) + 1):
for substr in substr_list:
anagrams[''.join(sorted(substr))].append(substr)
return [values for key, values in anagrams.iteritems() if len(values) > 1]
str = raw_input().strip()
print anagram_substring(str)
If you look at the current code complexity, it is O(n**2) in space complexity (since all substrings need to be saved).
Also, it is O(n**2)*O(k*log(k)) in time complexity, where O(n**2) is time to generate each substring for original string of length n, and O(k*log(k)) is time complexity to sort each substring of length k and save it as a key to be checked against later on.
In the worst case, k will approach n, so your time complexity would be O(log(n)*n**3) for the overall solution.
However, instead of sorting the keys, if you could just look up the keys for each substring, and compare against their values in other substrings, you would be good to go.
So consider solution below, which basically stores the count of each character within a substring in a Counter dictionary, and compares the Counters. Creation of counter as well as comparision of it is an O(k) operation. So that, the overall time complexity becomes O(n**3) in worst case.
Also note, your original output in the problem statement needs to be corrected: 'dapav', 'vadap' is a pair of anagrams that the output in the question is missing.
def find_anagram_substrings(s):
length = len(s)
substrings, substring_chars = [], {}
results = set()
for i in xrange(0, length):
for j in xrange(i+2, length+1):
substring = s[i:j]
substrings.append(s[i:j])
substring_chars[substring] = Counter(substring)
for s1, s2 in product(substrings, substrings):
if s1 != s2 and substring_chars[s1] == substring_chars[s2]:
results.add((s1, s2) if s1 < s2 else (s2, s1))
return results
print find_anagram_substrings("gnomeslikelemons")
Coming to the code in the original post, I've added a few suggestions on the naming conventions that could help make it more readable:
from collections import defaultdict
import itertools
# itertools is not used, no need to import
def anagram_substring(str):
substr_list = []
ans = []
# ans by itself does not clarify what it might contain.
# result could be a better choice of variable name
is_present = defaultdict(list)
# is_present is again an ambiguous choice of variable name
# it does not tell what values could it be storing
for i in xrange(len(str)):
# len(str) is used multiple times, can be a variable
for j in xrange(i+2, len(str)+1):
substr_list.append(str[i:j])
substr_list = list(set(substr_list))
# a set can be iterated normally, so why convert it back to list
for substr in substr_list:
if is_present[''.join(sorted(substr))]:
for anagram_str in is_present[''.join(sorted(substr))]:
ans.append([anagram_str,substr])
is_present[''.join(sorted(substr))].append(substr)
return ans
str = raw_input().strip()
print anagram_substring(str)
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2019-10-17 04:45:16
|
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https://www.directknowledge.com/diophantine-equations/
|
# Diophantine Equations (of the Linear Kind)
• By David A. Smith, Founder & CEO, Direct Knowledge
• David Smith has a B.S. and M.S. in Mathematics and has enjoyed teaching calculus, linear algebra, and number theory at both Tarrant County College and the University of Texas at Arlington. David is the Founder and current CEO of Direct Knowledge.
We solve linear Diophantine equations over the integers. In the two variable case, we provide a complete solution using the Euclidean Algorithm. Also, we will discuss the multi-variable case and provide examples.
We will take note of the fact that a Diophantine Equation of the linear kind seeks to equate the sum of two or more monomials, with at least one variable being of degree 1, to a constant. Again, the solutions to such equations are closely linked to modular arithmetic discussed earlier.
## Introduction
In the following Diophantine equations, $x$, $y$, and $z$ are the unknowns and the other letters are given constants. $$ax+by=1$$ This is a linear Diophantine equation. $$x^n+y^n=z^n$$ For $n = 2$ there are infinitely many solutions $(x,y,z)$: the Pythagorean triples. For larger integer values of $n$, Fermat’s Last Theorem states there are no positive integer solutions $(x, y, z)$. $$x^2-ny^2=\pm 1$$ This is Pell’s equation, which is named after the English mathematician John Pell. It was studied by Brahmagupta in the 7th century, as well as by Fermat in the 17th century. $$\frac{4}{n} = \frac{1}{x} + \frac{1}{y} + \frac{1}{z}$$
The Erdos-Straus conjecture states that, for every positive integer $n > 2$, there exists a solution in $x, y,$ and $z,$ all as positive integers. Although not usually stated in polynomial form, this example is equivalent to the polynomial equation $$4xyz = yzn + xzn + xyn = n(yz + xz + xy).$$
The term Diophantine equation usually refers to any equation in one or more unknowns that is to be solved in the integers.
The simplest kind of Diophantine equation is the linear Diophantine equation, namely $a x + b y = c$. In general, Diophantine equations furnish a natural vehicle for puzzles and problems of a mathematical nature.
## Two Variable Linear Diophantine Equations
Linear Diophantine Equations with two variables present interesting results. With two unknowns, they tend to have infinitely many solutions in the homogeneous case. However, their construction makes it easier to employ the Euclidean Algorithm, hence are easier to solve. Remember, cases may arise where the equation does not have proper solutions.
Theorem. (Linear Diophantine Equation) The linear Diophantine equation $a x+b y=c$ has a solution if and only if $d|c,$ where $d=(a,b).$ Moreover, if $\left(x_0,y_0\right)$ is a solution, then the set of solutions of the equation consists of pairs $(x,y)$ where \begin{equation*} x=x_0+\frac{t b}{d} \qquad \text{and} \qquad y=y_0-\frac{t a}{d} \end{equation*} and $t$ is an arbitrary integer.
Proof. Since $d=(a,b)$ there exists integers $m$ and $n$ such that $a m+b n=d$. Since $d|c$ we have an integer $k$ such that $c=d k$ and thus we have $(a m+b n)k=d k$. Thus, $a (m k)+b (n k)=c$ and so we have a solution.
Conversely, suppose $a x+b y=c$ has a solution say $x_1$ and $y_1.$ Then $a x_1+b y_1=c$ and since $d|a$ and $d|b$ we have $d|c.$ Let $x_0$ and $y_0$ be any solution. Then we have $a x_0+b y_0=c$ and so $$a x_0+\frac{t a b}{d}+b y_0-\frac{t a b}{d}=c$$ for any integer $t$ as needed.
It remains to show that all solutions $(x,y)$ have the correct form. Let $(x,y)$ be an arbitrary solution and let $\left(x_0,y_0\right)$ be any particular solution. Then we have $a\left(x-x_0\right)+b\left(x-x_0\right)=0$ and thus $a\left(x-x_0\right)=b\left(y_0-y\right).$ Now enter $d$. Dividing by $d,$ we have $$\frac{a}{d}\left(x-x_0\right)=\frac{b}{d}\left(y_0-y\right).$$ Observe that $$\left(\frac{a}{d},\frac{b}{d}\right)=1$$ and so $\frac{a}{d}\mid \left(y_0-y\right)$. Therefore, there exists an integer $s$ such that $y=y_0-\left(\frac{a}{d}\right)s$ and by substitution, $x=x_0+\left(\frac{b}{d}\right)s$ as desired.
## Solving Linear Diophantine Equations
While solving linear Diophantine equations is a straightforward process, this is not true for general Diophantine equations. In 1900, in recognition of their depth, David Hilbert proposed the solvability of all Diophantine problems as the tenth of his celebrated problems. In 1970, a novel result in mathematical logic known as Matiyasevich‘s theorem settled the problem negatively: in general, Diophantine problems are unsolvable.
We can check if a linear Diophantine equations is solvable and if so, actually find its solutions. The key ingredient in finding a particular solution is the Euclidean algorithm.
Example. Solve the linear Diophantine equation $14x+34y=90.$
Solution. Since $(14,34)=2$ and $2|90.$ There is a solution and so we need to find an initial solution. Since an initial solution is $x=4$ and $y=1$ we have all solutions $x=4+17 t$ and $y=1-7 t$ where $t\in\mathbb{Z}$.
Example. Solve the linear Diophantine equation $14x+35x=91.$
Solution. Since $(14,35)=7$ and $7|91$ the equation is solvable. Since an initial solution is $x=4$ and $y=1$ we have all solutions $x=4+2t$ and $y=1-5t$ where $t\in\mathbb{Z}$.
Example. Solve the linear Diophantine equation $14x+36y=93.$
Solution. Since $(14,36)=2$ and $2\nmid 93$ there are no solution to the linear Diophantine equation $14x+36y=93.$.
### Special Case
However, in this article, we will explore a simpler problem of special case Diophantine Equation of the linear type. Here, the solution to the problem is expressed as arbitrary integral values of a given constant. See the corollary below.
Corollary. If $(a,b)=1$ and if $x_0$ and $y_0$ is a particular solution of the linear Diophantine equation $a x+b y=c,$ then all solutions are given by $x=x_0+b t$ and $y=y_0-a t$ for integral values of $t.$
Proof. The proof follows immediately from the Theorem above.
For example, the equation $5x+22y=18$ has $x_0=8,$ $y_0=-1$ as one solution and so a complete solution is given by $x=8+22t$ and $y=-1-5t$ for arbitrary integral values of $t.$
## Multivariables Equations
A problem in Diophantus’ Arithmetica is to find four natural numbers whose sums by three are 20, 22, 24, and 27. Can you find these four integers?
Diophantus made important advances in mathematical notation, becoming the first person known to use algebraic notation and symbolism. Note that before him everyone wrote out equations completely. Furthermore, Diophantus introduced an algebraic symbolism that used an abridged notation for frequently occurring operations, and an abbreviation for the unknown and for the powers of the unknown.
Theorem. (General Linear Diophantine Equation) If $a_1,a_2,\ldots , a_n$ are nonzero positive integers, then the equation $$a_1x_1+ \cdots + a_nx_n = c$$ has an integral solution if and only if $d=\left(a_1,\ldots , a_n\right)$ divides $c.$ Furthermore, when there is a solution, there are infinitely many solutions.
Example. Which combinations of pennies, dimes, and quarters have a total value of $99$ cents?
Solution. Let $x,y,$ and $z$ be the number of pennies, dimes, and quarters, respectively. To solve this question, we will solve the linear Diophantine equation: $x+10y+25z=99.$ Since $x,y,$ and $z$ are all positive integers, it follows that $z=0,1,2,3;$ and so we can solve the 4 corresponding equations in only $x$ and $y.$ First, we solve $x+10y=99.$ Clearly, $x_0=99$ and $y_0=0$ is a particular solution and since $(1,10)=1$ all solutions are given by $x=99+10t$ and $y=0-t.$ By letting $t$ range from 0 to $-9$, we find some combinations of pennies, dimes, and quarters that total 99 cents: $$\begin{array}{c|cccccccccc} x & 99 & 89 & 79 & 69 & 59 & 49 & 39 & 29 & 19 & 9 \\ \hline y & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 \\ \hline z & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ \hline t & 0 & -1 & -2 & -3 & -4 & -5 & -6 & -7 & -8 & -9 \end{array}$$
## Applications of Linear Diophantine Equations
Continuing, we solve $x+10y=74.$ Clearly, $x_0=74$ and $y_0=0$ is a particular solution and since $(1,10)=1$ all solutions are given by $x=74+10t$ and $y=0-t.$ By letting $t$ range from 0 to $-7$, we find more combinations of pennies, dimes, and quarters that total 99 cents: $$\begin{array}{c|cccccccc} x & 74 & 64 & 54 & 44 & 34 & 24 & 14 & 4 \\ \hline y & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 \\ \hline z & 1 & 1 & 1 & 1 & 1 & 1 & 1 & 1 \\ \hline t & 0 & -1 & -2 & -3 & -4 & -5 & -6 & -7 \end{array}$$
Next, we solve $x+10y=49.$ Clearly, $x_0=49$ and $y_0=0$ is a particular solution and since $(1,10)=1$ all solutions are given by $x=49+10t$ and $y=0-t.$ By letting $t$ range from 0 to $-4$, we find more combinations of pennies, dimes, and quarters that total 99 cents: $$\begin{array}{c|ccccc} x & 49 & 39 & 29 & 19 & 9 \\ \hline y & 0 & 1 & 2 & 3 & 4 \\ \hline z & 2 & 2 & 2 & 2 & 2 \\ \hline t & 0 & -1 & -2 & -3 & -4 \end{array} \hspace{1cm} \begin{array}{c|ccc} x & 24 & 14 & 4 \\ \hline y & 0 & 1 & 2 \\ \hline z & 2 & 2 & 2 \\ \hline t & 0 & -1 & -2 \end{array}$$ Finally, we solve $x+10y=24.$ Clearly, $x_0=24$ and $y_0=0$ is a particular solution and since $(1,10)=1$ all solutions are given by $x=49+10t$ and $y=0-t.$ By letting $t$ range from 0 to $-2$, we find even more combinations of pennies, dimes, and quarters that total 99 cents.
## Exercises on Linear Diophantine Equations
Exercise. Solve the linear Diophantine equation by either finding all solutions or by showing there are none.
$(1) \qquad 3x+4y=7$
$(2) \qquad 17x+13y=100$
$(3) \qquad 30x+47y=-11$
$(4) \qquad 25x+95y=970$
$(5) \qquad 102x+1001y=1$
$(6) \qquad 7x+21 y+35z=8$
$(7) \qquad 6x+51y=22$
$(8) \qquad 33x+14y=115$
$(9) \qquad 14x+35y=93$
$(10) \qquad 56x+72y=40$
$(11) \qquad 24x+138y=18$
$(12) \qquad 221x+35y=11$
$(13) \qquad 18x+5y=48$
$(14) \qquad 54x+21y=906$
$(15) \qquad 158x-57y=7$
$(16) \qquad 41x-51y=223$
Exercise. Solve the linear Diophantine equation $7101x+102y+103z=1$ by either finding all solutions or by showing there are none.
Exercise. A grocer order apples and oranges at a total cost of $\$ 8.39.$If apples cost him$25$cents each and oranges cost him 18 cents each, how many of each type of fruit did he order? Exercise. A postal clerk has only$14$cents and$21$cent stamps to sell. What combination of these may be used to mail a package requiring postage of exactly \$$4.00.$
Exercise. Divide 100 into two summands such that one is divisible by 7 and the other by 11.
Exercise. Is it possible to have 50 coins, all of which are pennies, dimes, or quarters, with a total worth 3 dollars.
## More Exercises on Linear Diophantine Equations
Exercise. When Mr. Smith cached a check at his bank, the teller mistook the number of cents for the number of dollars and vice versa. Unaware of this, Mr. Smith spent 68 cents and then noticed, to his surprise, that he had twice the amount of the original check. Determine the smallest value for which the check could have been written.
Exercise. Divide 100 into two summands such that one is divisible by 7 and the other by 11.
Exercise. A man has 5 diamonds, 8 rubies, 7 sapphires, and 83 gold coins; a second man has 7,9,6, and 74 of these items, respectively; a third man has 3, 13, 11, and 80. If the collections are considered equally valuable, how many gold coins is each diamond, ruby, and sapphire writ?
Exercise. Solve the linear Diophantine equation, $714x+7007y=7.$
Exercise. Solve the linear Diophantine equation by either finding all solutions or by showing there are none for $17x+13y=100.$
Exercise. Solve the linear congruence $5x\equiv 7 \pmod{57}$ using basic properties of congruence (no linear Diophantine equation). Show all your steps.
Exercise. Explain why the linear Diophantine equation $2x-101y=82$ is solvable or not solvable.
If possible find all solutions.
Exercise. Solve the linear congruence $5x\equiv 15 \pmod{35}$ by solving a linear Diophantine equation. Show all your steps.
Exercise. Solve the congruence $3x\equiv 5 \pmod{16}$ by writing a linear Diophantine equation and solving it.
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2020-08-11 00:11:29
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https://electronics.stackexchange.com/questions/326304/why-do-electrolytics-have-a-different-charge-and-discharge-rate-for-the-same-cur
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# Why do electrolytics have a different charge and discharge rate for the same current
I am measuring the charge and discharge rate of a HV electrolytic capacitor (actually three 560uF, 250V capacitors in series) to calculate the capacitance. Note: The capacitors are hand picked for an effective combined AC capacitance of 155uF.
During charge I source 20mA and measure (digitize) from 35V to 695V. During discharge I sink 20mA and measure (digitize) from 695V to 35V.
The curves are really flat (the charge has a very slight curve).
Computed capacitance (20 runs) using C=$I / {dV\over dt}$ is:
• Charge - 166.13uF +/-0.7uF (2nd order polynomial fit)
• Discharge - 185.16uF +/-0.08uF (linear fit)
Why is the discharge capacitance consistently 11% higher?
Note: Reforming is not an issue as the test was repeated 20 times in quick succession with consistent results.
Test is performed by sourcing the current with a Keithley 2410 SMU. Voltage is measured using a calibrated 1000:1 divider into a waveform digitizer. The voltage divider is buffered and has a 10M input impedance.
Here are the charge and discharge curves.
• Too confused by what you are actually measuring and how you are doing the math here to comment. – Trevor_G Aug 28 '17 at 20:01
• results indicate you are discharging with more energy than you put in as C increased on discharge, suggesting error somewhere. – Tony Stewart Sunnyskyguy EE75 Aug 28 '17 at 20:50
• How do you generate the constant current source and sink? Could it be possible that the two directions have 11% difference? Handling the 695 V level is not an easy feat... – Ale..chenski Aug 28 '17 at 21:16
• Did you try your experiment with just a resistor, same during charge, and discharge? – Ale..chenski Aug 28 '17 at 21:21
• Possibly @markshancock, unfortunately, as a question on here, it is impossible to comment with any degree of certainty on your results when the math involved, with whatever errors are introduced due to measurement cycle lag etc. is indeterminate. We cant compare apples and oranges. Either way, something is off if your results are stating you are getting 10% more charge out of them than you are putting in. If you can productize that phenomenon you will be rich indeed. – Trevor_G Aug 29 '17 at 19:55
Two suggestions:
The curves are really flat (the charge has a very slight curve).
The charge has a curve because your caps are unbalanced. One of them has lower capacitance, it charges faster than the others, then it hits breakdown voltage and begins to leak. When discharging the issue does not exist. Thus charge is curved, but discharge is not.
How to distinguish this from soakage/dielectric absorption: charge, then wait monitoring current, if dielectric absorption is not involved then current will be negligible.
Suggestion 2 is I'm wrong ;) in this case I'm interested in the real answer!
• +1 Do you know what is the spice model for overvoltaged electrolytic cap? I'd like to see this scenario in simulations.. – Ale..chenski Aug 28 '17 at 22:50
• I don't know and I'm pretty sure if I asked the manufacturer for a model of a part used outside its specifications they would ask... what the wat? So, no idea. All I can tell is when I over-voltag-ed some caps smelly things happened... and on other times it worked fine. Wouldn't trust my life on it though.. – peufeu Aug 28 '17 at 22:58
• Would advise the OP to check the voltage on each cap during charge compared to ratings. I mean, I rode a bicycle downhill 80 km/h. Maybe more, I didn't have time to look at the speedo due due to trees and shit blurring past at insane speed. That's a bit above ratings. Really fun to do... but I wouldn't advise it for, like, everyday use, y'know. – peufeu Aug 28 '17 at 23:06
• Working voltage for each cap is 250V and surge is 300V. I am staying below both. Capacitors are hand selected to have closely matched capacitances (supposedly within 2%) - I am sure they are within 10%. – markshancock Aug 28 '17 at 23:13
• This test does not monitor each capacitor; but, I have another that does. Typically the voltages across the capacitors differ by <5V. – markshancock Aug 28 '17 at 23:18
So ultimately The problem was with the curve
In both cases (charge and discharge), the overall rate is very similar. The problem is that there is a very slight curve in the case of the charge. This is pretty much expected. As the voltage increases, the current required to feed the leakage resistance increases thus stealing more and more current from the capacitor and thus reducing the ${dV\over dt}$. Since I am doing a 2nd order polynomial fit and using the 1st order term for the capacitance calculation, this is equivalent of using the ${dV\over dt}$ at t=0 which is where it is highest. This does make since this is where leakage has the least effect. Since C=$I / {dV\over dt}$, I will get a generally lower value of capacitance.
Here are the details of the curve fits
• Charge
2nd Order: y = -1.941x2 + 120.99x + 25.775 => C=165.3
1st Order: y = 109.07x + 37.977 => C=183.4
• Discharge
2nd Order: y = 0.6011x2 - 111.69x + 693.51 => C=179.1
1st Order: y = -107.97x + 689.66 => C=185.2
This explains the reason for the different calculated values; but, it does not explain why the curve does not show up on the discharge as well.
Note: On review, I realized that if I decide to do a 2nd order fit for the discharge I will need to make sure to use ${dV\over dt}$ at y=0 which for the discharge is not t=0 and thus is not the 1st order term.
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2020-02-17 11:59:45
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https://alphons.io/1673/what-is-the-formula-of-the-centripetal-force-based-on-linear-speed/
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👋 Hello! I'm Alphonsio the robot. Ask me a question, I'll try to answer.
What is the formula of the centripetal force based on linear speed?
The centripetal force can be calculated with the following formula:
The previous formula can be generalized in vector form:
Where:
• is the centripetal force expressed in Newton ()
• is the body mass expressed in kilograms ()
• is the linear velocity of the body expressed in meters per second ()
• is the radius of the circular path expressed in meters ()
• is a radius vector attached to the center of the circular path, in the direction of the body.
More
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2021-04-13 07:03:34
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https://blog.csdn.net/WWL_521_Forever/article/details/79956839
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# 自己编辑的英语stem课程
Lesson 1 Excuse me!
对不起！
Listen to the tape then answer this question. Whose handbag is it?
听录音，然后回答问题，这是谁的手袋？
Excuse me!
Yes?
Is this your handbag?
Pardon?
Is this your handbag?
Yes, it is.
Thank you very much.
New Word and expressions 生词和短语
excuse
v. 原谅
me
pron.我(宾格)
yes
is
v. be 动词现在时第三人称单数
this
pron.这
your
handbag
n. （女用）手提包
pardon
int. 原谅，请再说一遍
it
pron.它
thank you
感谢你（们）
very much
非常地
对不起
什么事？
这是您的手提包吗？
对不起，请再说一遍。
这是您的手提包吗？
是的，是我的。
非常感谢！
（偶数课为习题，无课文）
Lesson 3 Sorry, sir.
对不起，先生。
Listen to the tape then answer this question.
My coat and my umbrella please.
Here is my ticket.
Thank you, sir.
Number five.
This is not my umbrella.
Sorry sir.
Is this your umbrella?
No, it isn't.
Is this it?
Yes, it is.
Thank you very much.
New words and Expressions 生词和短语
umbrella
n. 伞
int. 请
here
my
ticket
n. 票
number
n. 号码
five
num. 五
sorry
sir
n. 先生
cloakroom
n. 衣帽存放处
请把我的大衣和伞拿给我。
这是我（寄存东西）的牌子。
谢谢，先生。
是5号。
这是您的伞和大衣
这不是我的伞。
对不起，先生。
这把伞是您的吗？
不，不是！
这把是吗？
是，是这把
非常感谢。
Lesson 5 Nice to meet you
很高兴见到你。
Listen to the tape then answer this question. Is Chang-woo Chinese?
MR. BLAKE: Good morning.
STUDENTS: Good morning, Mr. Blake.
MR. BLAKE: This is Miss Sophie Dupont.
Sophie is a new student.
She is French.
MR. BLAKE: Sophie, this is Hans.
He is German.
HANS: Nice to meet you.
MR. BLAKE: And this is Naoko.
She's Japanese.
NAOKO: Nice to meet you.
MR. BLAKE: And this is Chang-woo.
He's Korean.
CHANG-WOO: Nice to meet you.
MR. BLAKE: And this is Luming.
He is Chinese.
LUMNG: Nice to meet you.
MR. BLAKE: And this is Xiaohui.
She's Chinese, too.
XIAOHUI: Nice to meet you.
New Word and expressions 生词和短语
Mr.
先生
good
Miss
小姐
new
student
n. 学生
French
adj. & n. 法国人
German
adj. & n. 德国人
nice
meet
v. 遇见
Japanese
adj. & n. 日本人
Korean
adj. & n. 韩国人
Chinese
adj. & n. 中国人
too
Lesson 7 Are you a teacher?
你是教师吗？
Listen to the tape then answer this question. What is Rober's job?
ROBERT: I am a new student.
My name's Robert.
SOPHIE: Nice to meet you.
My name's Sophie.
ROBERT: Are you French?
SOPHIE: Yes, I am.
SOPHIE: Are you French too?
ROBERT: No, I am not.
SOPHIE: What nationality are you?
ROBERT: I'm Italian.
ROBERT: Are you a teacher?
SOPHIE: No, I'm not.
ROBERT: What's your job?
SOPHIE: I'm a keyboard operator.
SOPHIE: What's your job?
ROBERT: I'm an engineer.
New Word and expressions 生词和短语
I
pron.我
am
v. be 动词现在时第一人称单数
are
v. be 动词现在时复数
name
n. 名字
what
adj. & pron. 什么
nationality
n. 国籍
job
n. 工作
keyboard
n. 电脑键盘
operator
n. 操作人员
engineer
n. 工程师
Lesson 9 How are you today?
今天好吗？
Listen to the tape then answer this question. How is Emma?
STEVEN: Hello, Helen.
HELEN: Hi, Steven.
STEVEN: How are you today?
HELEN: I'm very well, thank you.
And you?
STEVEN: I'm fine, thanks.
STEVEN: How is Tony?
HELEN: He's fine, thanks.
How's Emma?
STEVEN: She's very well, too, Helen.
STEVEN: Goodbye, Helen.
Nice to see you.
HELEN: Nice to see you, too, Steven.
Goodbye.
New Word and expressions 生词和短语
hello
int. 喂（表示问候）
hi
int. 喂，嗨
how
well
fine
thanks
int. 谢谢
goodbye
int. 再见
see
v. 见
Lesson 11 Is this your shirt?
这是你的衬衫吗？
Listen to the tape then answer this question. Whose shirt is white?
HEACHER：Whose shirt is that?
HEACHER：Is this your shirt, Dave?
DAVE: No. Sir.
It's not my shirt.
DAVE: This is my shirt.
My shirt's blue.
TEACHER: Is this shirt Tim's?
DAVE: Perhaps it is, sir.
Tim's shirt's white.
HEACHER：Tim!
TIM: Yes, sir?
HEACHER：Is this your shirt?
TIM: Yes, sir.
HEACHER：Here you are.
Catch!
TIM: Thank you, sir.
New Word and expressions 生词和短语
whose
pron.谁的
blue
perhaps
white
catch
v. 抓住
Lesson 13 A new dress
一件新连衣裙
Listen to the tape then answer this question. What colour is Anna's hat?
LOUISE: What colour's your new dress?
ANNA: It's green.
ANNA: Come upstairs and see it.
LOUISE: Thank you.
ANNA: Look!
Here it is!
LOUISE: That's nice dress.
It's very smart.
ANNA: My hat's new, too.
LOUISE: What colour is it?
ANNA: It's the same colour.
It's green, too.
LOUISE: That is a lovely hat!
New Word and expressions 生词和短语
colour
n. 颜色
green
come
v. 来
upstairs
smart
hat
n. 帽子
same
lovely
Lesson 15
请出示你们的护照。
Listen to the tape then answer this question. Is there a problem with the Customs officer?
CUSTOMS OFFICER: Are you Swedish?
GIRLS: No, we are not.
We are Danish.
CUSTOMS OFFICER: Are your friends Danish, too?
GIRLS: No, they aren't.
They are Norwegian.
GIRLS: Here they are.
CUSTOMS OFFICER: Are these your cases?
GIRLS: No, they aren't.
GIRLS: Our cases are brown.
Here they are.
CUSTOMS OFFICER: Are you tourists?
GIRLS: Yes, we are.
CUSTOMS OFFICER: Are your friends tourists too?
GIRLS: Yes, they are.
CUSTOMS OFFICER: That's fine.
GIRLS: Thank you very much.
New Word and expressions 生词和短语
customs
n. 海关
officer
n. 官员
girl
n. 女孩，姑娘
Danish
friend
n. 朋友
Norwegian
adj. & n. 挪威人
passport
n. 护照
brown
tourist
n. 旅游者
Lesson 17
How do you do?
你 好！
Listen to the tape then answer this question. What are Michael Maker and Jeremy Short's jobs?
MR. JACKSON: Come and meet our
employees, Mr.Richards.
MR. RICHARDS: Thank you, Mr. Jackson.
MR. JACKSON: This is Nicola Grey,
and this is Claire Taylor.
MR. RICHARDS: How do you do?
MR. RICHARDS: Those women are very hard-working.
What are their jobs?
MR. JACKSON: They're keyboard operators.
MR. Jackson: This is Michael Baker,
and this is Jeremy Short.
MR. RICHARDS: How do you do?
MR. RICHARDS: They aren't very busy!
What are their jobs?
MR. JACKSON: They're sales reps.
They're very lazy.
MR. RICHARDS: Who is this young man?
MR. JACKSON: This is Jim.
He's our office assistant.
New Word and expressions 生词和短语
employee
n. 雇员
hard-working
sales reps
推销员
man
n. 男人
office
n. 办公室
assistant
n. 助手
理查兹先生。
这位是克莱尔.泰勒。
她们是做什么工作的？
这位是杰里米.肖特。
他们是做什么工作的？
是我们办公室的勤杂人员。
Lesson 19
Tired and thirsty
又累又渴
Listen to the tape then answer this question. Why do the children thank their mother?
MOTHER: What's the matter, children?
GIRL: We're tired …
BOY: … and thirsty, Mum.
MOTHER: Sit down here.
MOTHER: Are you all right now?
BOY: No, we aren't.
MOTHER: Look!
There's an ice cream man.
MOTHER: Two ice cream please.
MOTHER: Here you are, children.
CHILDREN: Thanks, Mum.
GIRL: These ice creams are nice.
MOTHER: Are you all right now?
CHILDREN: Yes, we are, thank you!
New Word and expressions 生词和短语
matter
n. 事情
children
n. 孩子们（child的复数）
tired
boy
n. 男孩
thirsty
Mum
n. 妈妈（儿语）
sit down
坐下
right
ice cream
冰淇淋
Lesson 21
Which book?
哪一本书？
Listen to the tape then answer this question. Which book does the man want?
MAN: Give me a book please, Jane.
WOMAN: Which book?
WOMAN: This one?
MAN: No, not that one. The red one.
WOMAN: This one?
WOMAN: Here you are.
MAN: Thank you.
New Word and expressions 生词和短语
give
v. 给
one
pron.一个
which
question word 哪一个
Lesson 23
Which glasses?
哪几只杯子？
Listen to the tape then answer this question. Which glasses does the man want?
MAN: Give me some glasses please, Jane.
WOMAN: Which glasses?
WOMAN: These glasses?
MAN: No, not those.
The one on the shelf.
WOMAN: These?
WOMAN: Here you are.
MAN: Thanks.
New Word and expressions 生词和短语
on
prep.在……之上
shelf
n. 架子，搁板
Lesson 25
Mrs. Smith's Kitchen
史密斯太太的厨房
Listen to the tape then answer this question. What colour is the electric cooker?
Mrs. Smith's kitchen is small.
There is a refrigerator in the kitchen.
The refrigerator is white.
It is on the right.
There is an electric cooker in the kitchen.
The cooker is blue.
It is on the left.
There is a table in the middle of the room.
There is a bottle on the table.
The bottle is empty.
There is a cup on the table, too.
The cup is clean.
New Word and expressions 生词和短语
Mrs.
夫人
kitchen
n. 厨房
refrigerator
n. 电冰箱
right
n. 右边
electric
left
n. 左边
cooker
n. 炉子，炊具
middle
n. 中间
of
prep.（属于）……的
room
n. 房间
cup
n. 杯子
史密斯夫人的厨房很小。
厨房里有个电冰箱。
冰箱的颜色是白的。
它位于房间右侧。
厨房里有个电灶。
电灶的颜色是蓝的。
它位于房间左侧。
房间的中央有张桌子。
桌子上有个瓶子。
瓶子是空的。
桌子上还有一只杯子。
杯子很干净。
Lesson 27
Mrs. Smith's living room
史密斯太太的客厅
Listen to the tape then answer this question. Where are the books?
Mrs. Smith's living room is large.
There is a television in the room.
The television is near the window.
There are some magazines on the television.
There is a table in the room.
There are some newspapers on the table.
There are some armchairs in the room.
The armchairs are near the table.
There is a stereo in the room.
The stereo is near the door.
There are some books on the stereo.
There are some pictures in the room.
The pictures are on the wall.
New Word and expressions 生词和短语
living room
客厅
near
prep.靠近
widow
n. 窗户
armchair
n. 扶手椅
door
n. 门
picture
n. 图画
wall
n. 墙
史密斯夫人的客厅很大。
客厅里有台电视机。
电视机靠近窗子。
电视机上放着几本杂志。
客厅里有张桌子。
桌上放着几份报纸。
客厅里有几把扶手椅。
那些扶手椅靠近桌子。
客厅里有台立体声音响。
音响靠近门。
音响上面有几本书。
客厅里有几幅画。
画挂在墙上。
Lesson 29
Come in, Amy.
进来，艾米。
Listen to the tape then answer this question. How must Amy clean the floor?
MRS. JONES: Come in, Amy.
MRS. JONES: Shut the door, please.
MRS. JONES: This bedroom's very untidy.
MAY: What must I do, Mrs. Jones?
MRS. JONES: Open the window and air the room.
MRS. JONES: Then put these clothes in the wardrobe.
MRS. JONES: Then make the bed.
MRS. JONES: Dust the dressing table.
MRS. JONES: Then sweep the floor.
New Word and expressions 生词和短语
shut
v. 关门
bedroom
n. 卧室
untidy
must
modal verb 必须，应该
open
v. 打开
air
v. 使 … 通风，换换空气
put
v. 放置
clothes
n. 衣服
wardrobe
n. 大衣柜
dust
v. 掸掉灰尘土
sweep
v. 扫
Lesson 31
Where's Sally?
萨莉在哪里？
Listen to the tape then answer this question. Is the cat climbing the tree?
JEAN: Where's Sally, Jack?
JACK: She's in the garden, Jean.
JEAN: What's the doing?
JACK: She's sitting under the tree.
JEAN: Is Tim in the garden, too?
JACK: Yes, he is.
He's climbing the tree.
JEAN: I beg your pardon?
Who's climbing the tree?
JACK: Tim is.
JEAN: What about the dog?
JACK: The dog's in the garden, too.
It's running across the grass.
It's running after a cat.
New Word and expressions 生词和短语
garden
n. 花园
under
prep.在……这下
tree
n. 树
climb
v. 爬，攀登
who
pron.谁
run
v. 跑
grass
n. 草，草地
after
prep.在……之后
across
prep.横过，穿过
cat
n. 猫
琼：杰克，萨莉在哪儿？
琼：她在干什么？
琼：蒂姆也在花园里吗？
琼：你说什么？谁在爬树？
琼：那么狗呢？
在追一只猫。
Lesson 33
A fine day
晴天
Listen to the tape then answer this question. Where is the Jones family?
It is a fine day today.
There are some clouds in the sky,
but the sun is shining.
Mr. Jones is with his family.
They are walking over the bridge.
There are some boats on the river.
Mr. Jones and his wife are looking at them.
Sally is looking at a big ship.
The ship is going under the bridge.
Tim is looking at an aeroplane.
The aeroplane is flying over the river.
New Word and expressions 生词和短语
day
n. 日子
cloud
n. 云
sky
n. 天空
sun
n. 太阳
shine
v. 照耀
with
prep. 和……在一起
family
n. 家庭（成员）
walk
v. 走路, 步行
over
prep.跨越，在……之上
bridge
n. 桥
boat
n. 船
river
n. 河
ship
n. 轮船
aeroplane
n. 飞机
fly
v. 飞
今天天气好。
天空中飘着几朵云，但阳光灿烂。
琼斯先生同他的家人在一起。
他们正在过桥。
河上有几艘船。
琼斯先生和他的妻子正在看这些船。
莎莉正在观看一艘大船。
那船正从桥下驶过。
蒂姆正望着一架飞机。
飞机正从河上飞过。
Lesson 35
Our village
我们的村庄
Listen to the tape then answer this question. Are the children coming out of the park or going into it?
This is a photograph of our village.
Our village is in a valley.
It is between two hills.
The village is on a river.
Here is another photograph of the village.
My wife and I are walking
along the banks of the river.
We are on the left.
There is a boy in the water.
He is swimming across the river.
Here is another photograph.
This is the school building.
It is beside a park.
The park is on the right.
Some children are coming out of the building.
Some of them are going to the park.
New Word and expressions 生词和短语
photograph
n. 照片
village
n. 村庄
valley
n. 山谷
between
prep.在……之间
hill
n. 小山
another
det. 另一个
wife
n. 妻子
along
prep.沿着
bank
n. 河岸
water
n. 水
swim
v. 游泳
building
n. 大楼，建筑物
park
n. 公园
into
prep.进入
这是我们村庄的一张照片。
我们的村庄坐落在一个山谷之中。
它们于两座小山之间。
它靠近一条小河。
这是我们村庄的另一张照片。
我和妻子沿河岸走着。
我们在河的左侧。
河里面有个男孩。
他正横渡小河。
这是另一张照片。
这是学校大楼。
它位于公园的旁边。
公园在右面。
一些孩子正从楼里出来。
他们中有几个正走进公园。
Lesson 37
Making a bookcase
做书架
Listen to the tape then answer this question. What is Susan's favourite colour?
DAN: You're working hard, George.
What are you doing?
GEORGE: I'm making a bookcase.
GEORGE: Give me that hammer please, Dan.
DAN: Which hammer?
This one?
GEORGE: No, not that one.
The big one.
DAN: Here you are.
GEORGE: Thanks, Dan.
DAN: What are you doing to do now,
George?
GEORGE: I'm going to paint it.
DAN: What colour are you going
to pain it?
GEORGE: I'm going to paint it pink.
DAN: Pink!
GEORGE: This bookcase isn't for me.
It's for my daughter, Susan.
Pink's her favourite colour.
New Word and expressions 生词和短语
work
v. 工作
hard
make
v. 做
bookcase
n. 书橱，书架
hammer
n. 锤子
paint
v. 上漆，涂
pink
favourite
是为我的女儿苏珊做的。
粉红色是她最喜欢的颜色。
Lesson 39
Don't drop it!
别摔了！
Listen to the tape then answer this question. Where does Sam put the vase in the end?
SAM: What are you going to do with
that vase, Penny?
PENNY: I'm going to put it on this
table, Sam.
SAM: Don't do that.
Give it to me.
PENNY: What are you going to do with it?
SAM: I'm going to put it here,
in front of the window.
PENNY: Be careful!
Don't drop it!
PENNY: Don't put there, Sam.
Put it here,
on this shelf.
SAM: There we are!
It's a lovely vase.
PENNY: Those flowers are lovely, too.
New Word and expressions 生词和短语
front
n. 前面
in front of
在……之前
careful
vase
n. 花瓶
drop
v. 掉下
flower
n. 花
Lesson 41
Penny's bag
彭妮的提包
Listen to the tape then answer this question. Who is the tin of tobacco for?
SAN: Is that bag heavy, Penny?
PENNY: Not very.
SAN: Here!
Put it on this chair.
What's in it?
PENNY: A piece of cheese.
A loaf of bread.
A bar of soap.
A bar of Chocolate.
A bottle of milk.
A pound of sugar.
Half a pound of coffee.
A quarter of pound of tea.
And a tin of tobacco.
SAN: Is that tin of tobacco for me?
PENNY: Well, it's certainly not for me!
New Word and expressions 生词和短语
cheese
n. 乳酪，干酪
n. 面包
soap
n. 肥皂
chocolate
n. 巧克力
sugar
n. 糖
coffee
n. 咖啡
tea
n. 茶
tobacco
n. 烟草，烟丝
里面是什么东西？
一块巧克力、一瓶牛奶、一磅糖、
半磅咖啡、1/4 磅茶叶和一听烟丝。
Lesson 43
Hurry up!
快点！
Listen to the tape then answer this question. How do you know Sam doesn't make the tea very often?
PENNY: Can you make the tea, Sam?
SAM: Yes, of course I can, Penny.
SAM: Is there any water in this
kettle?
PENNY: Yes, there is.
SAM: Where's the tea?
PENNY: It's over there,
behind the teapot.
PENNY: Can you see it?
SAM: I can see the teapot,
but I can't see the tea.
PENNY: There it is!
It's in front of your!
SAM: Ah yes, I can see it now.
SAM: Where are the cups?
PENNY: There are some in the cupboard.
PENNY: Can you find them?
SAM: Yes. Here they are.
PENNY: Hurry up, Sam!
The kettle's boiling!
New Word and expressions 生词和短语
of course
当然
kettle
n. 水壶
behind
prep.在……后面
teapot
n. 茶壶
now
find
v. 找到
boil
v. 沸腾，开
Lesson 45
The boss's letter
老板的信
Listen to the tape then answer this question. Why can't Pamela type the letter?
THE BOSS: Can you come here a minute
BOB: Yes, sir?
THE BOSS: Where's Pamela?
BOB: She's next door.
She's in her office, sir.
THE BOSS: Can she type
this letter for me?
BOB: Yes, sir.
BOB: Can you type this letter
for the boss please, Pamela?
PAMELA: Yes, of course I can.
BOB: Here you are.
PAMELA: Thank you, Bob.
PAMELA: Bob!
BOB: Yes?
What's the letter.
PAMELA: I can't type this letter.
PAMELA: I can't read it!
The boss's handwriting is
terrible!
New Word and expressions 生词和短语
can
modal verb 能够
boss
n. 老板，上司
minute
n. 分（钟）
v. 请求，要求
handwriting
n. 书写
terrible
帕梅拉？
老板的书写太糟糕了！
Lesson 47
A cup of coffee
一杯咖啡
Listen to the tape then answer this question. How does Ann like her coffee?
CHRISTINE: Do you like coffee, Ann?
ANN: Yes, I do.
CHRISTINE: Do you want a cup?
ANN: Yes, please, Christine.
CHRISTINE: Do you want any sugar?
CHRISTINE: Do you want any milk?
ANN: No, thank you.
I don't like milk in my coffee.
I like black coffee.
CHRISTINE: Do you like biscuits?
ANN: Yes. I do.
CHRISTINE: Do you want one?
New Word and expressions 生词和短语
like
v. 喜欢，想要
want
v. 想
安：是的，我喜欢。
安：好的，请来一杯，克里斯廷。
安：好的，请放一些。
安：不了，谢谢。我不喜欢咖啡中放牛奶，我喜欢咖啡。
安：是的，我喜欢。
安：好的，请来一块。
Lesson 49
At the butcher's
在肉店
Listen to the tape then answer this question. What does Mr. Bird like?
BUTCHER: Do you want any meat today.
Mrs. Bird?
BUTCHER: Do you want beef or lamb?
BUTCHER: This lamb's very good.
MRS.BIRD: I like lamb,
but my husband doesn't.
BUTCHER: What about some steak?
This is a nice piece.
MRS.BIRD: Give me that piece, please.
MRS.BIRD: And a pound of mince, too.
BUTCHER: Do you want a chicken,
Mrs. Bird?
They 're very nice.
MRS.BIRD: No, thank you.
MRS.BIRD: My husband likes steak,
but he doesn't like chicken.
BUTCHER: To tell you the truth,
Mrs. Bird,
I don't like chicken either!
New Word and expressions 生词和短语
butcher
n. 卖肉的
meat
n. （食用）肉
beef
n. 牛肉
lamb
n. 羔羊肉
husband
n. 丈夫
steak
n. 牛排
mince
n. 肉馅，绞肉
chicken
n. 鸡
tell
v. 告诉
truth
n. 实情
either
我也不喜欢鸡。
Lesson 51
A pleasant climate
宜人的气候
Listen to the tape then answer this question. Does it ever snow In Greece?
HANS: Where do you come from?
DIMITRI: I come from Greece.
HANS: What's the climate like
DIMITRI: It's very pleasant.
HANS: What's the weather
like in spring?
DIMITRI: It's often windy in March.
It's always warm in April
and May,
but it rains sometimes.
HANS: What's it like in summer?
DIMITRI: It's always hot
in June, July and August.
The sun shines every day.
HANS: Is it cold or warm in autumn?
DIMITRI: It's always warm
in September and October.
It's often cold in November
and it rains sometimes.
HANS: Is it very cold in winter?
DIMITRI: It's often cold
in December, January
and February.
It snows sometimes.
New Word and expressions 生词和短语
Greece
n. 希腊
climate
n. 气候
country
n. 国家
pleasant
weather
n. 天气
spring
n. 春季
windy
warm
rain
v. 下雨
sometimes
summer
n. 夏天
autumn
n. 秋天
winter
n. 冬天
snow
v. 下雪
January
n. 1月
February
n. 2月
March
n. 3月
April
n. 4月
May
n. 5月
June
n. 6月
July
n. 7月
August
n. 8月
September
n. 9月
October
n. 10月
November
n. 11月
December
n. 12月
4月和5月的天气总暖洋洋的，
但有时下雨。
每天都出太阳。
11月常常就冷了，而且有时下雨。
有时还下雪。
Lesson 53
An interesting climate
有趣的气候
Listen to the tape then answer this question. What is the favourite subject of conversation in England?
HANS: Where do you come from?
JIM: I come from England.
HANS: What's the climate like in your
country?
JIM: It's mild,
but it's not always pleasant.
JIM: The weather's often cold
in North and windy in the East.
It's often wet in the West
and sometimes warm in the south.
HANS: Which seasons do you like best?
JIM: I like spring and summer.
The days are long and the night
are short.
The sun rises early and sets late.
JIM: I don't like autumn and winter.
The days are short
and the nights are long.
The sun rises late
and set early.
Our climate is not very good,
but it's certainly interesting.
It's our favourite subject
of conversation.
New Word and expressions 生词和短语
mild
always
north
n. 北方
east
n. 东方
wet
west
n. 西方
south
n. 南方
season
n. 季节
best
night
n. 夜晚
rise
v. 升起
early
set
v. （太阳）落下去
late
interesting
subject
n. 话题
conversation
n. 谈话
东部则常常利风。
西部常下雨，南部有时则很暖和。
因为此时白天短而夜晚长，
太阳升得迟而落得早。
虽然我们国家的气候并不很好，
但又确实很有意思。
天气是我们最喜欢谈论的话题。
Lesson 55
The Sawyer family
索耶一家人
Listen to the tape then answer this question. When do the children do their homework?
The Sawyer live at 87 King Street.
In the morning, Mr. Sawyer goes to work and the children go to school.
Mrs. Sawyer stays at home every day. She does the housework.
She always eats her lunch at noon.
In the afternoon, she usually sees her friends. They often drink tea together.
In the evening, the children come home from school. They arrive home early.
Mr. Sawyer comes home from work. He arrives home late.
At night, the children always do their homework. Then they go to bed. Mr. Sawyer usually reads his newspaper, but sometimes he and his wife watch television.
New Word and expressions 生词和短语
live
v. 住，生活
stay
v. 呆在，停留
home
n. 家；
housework
n. 家务
lunch
n. 午饭
afternoon
n. 下午
usually
together
evening
n. 晚上
arrive
v. 到达
night
n. 夜间
索耶一家住在国王街87号。
早上，索耶先生去上班，孩子们去上学。父亲每天送孩子们去上学。
索耶夫人每天呆在家里。她料理家务。
她总是在正午吃午饭。
下午，她总是会见她的朋友。她们经常在一起喝茶。
傍晚，孩子们放学回家。他们到家很早。
索耶先生下班回家。他到家很晚。
晚上，孩子们总是做作业，然后去睡觉。索耶先生总是读报纸，但有时和他的妻子一起看电视。
Lesson 57
An unusual day
很不平常的一天
Listen to the tape then answer this question. What is Mr. Sawyer doing tonight?
It is eight o'clock. The children go to school by car every day, but today, they are going to school on foot.
It is ten o'clock. Mrs. Sawyer usually stays at home in the morning, but this morning, she is going to the shops.
It is four o'clock. In the afternoon, Mrs. Sawyer usually drinks tea in the living room. But this after, she is drinking tea in the garden.
It is six o'clock. In the evening, the children usually do their homework, but this evening, they are not doing their homework. At the moment, they are playing in the garden.
It is nine o'clock. Mr. Sawyer usually reads his newspaper at night. But he's not reading his newspaper tonight. At the moment, he's reading an interesting book.
New Word and expressions 生词和短语
o'clock
shop
n. 商店
moment
n. 片刻，瞬间
现在是8点钟。孩子们每天都乘小汽车去上学，而今天，他们正步行上学。
现在是10点钟。上午，索耶夫人通常是呆在家里的，但今天上午，她正去商店买东西。
现在是4点钟，下午，索耶夫人通常是在客厅里喝茶，但今天下午，她正在花园里喝茶。
现在是6点钟。晚上，孩子们通常是做作业，而今天晚上，他们没做企业。此刻，他们正在花园里玩。
现在是9点钟。索耶先生通常是在晚上看报，但今天晚上他没看报。此刻，他正在看一本有趣的书。
Lesson 59
Is that all?
就这些吗？
Listen to the tape then answer this question. Does the lady buy and chalk?
LADY: I want some envelopes,
SHOP ASSISTANT: Do you want the
large size or the
small size?
LADY: Do you have any
writing paper?
SHOP ASSISTANT: Yes, we do.
SHOP ASSISTANT: I don't have any small
pads. I only have large
one. Do you want a pad?
LADY: And I want some glue.
SHOP ASSISTANT: A bottle of glue.
LADY: And I want a large box
of chalk, too.
SHOP ASSISTANT: I only have small boxes.
Do you want one?
LADY: No, thank you.
SHOP ASSISTANT: Is that all?
LADY: That's all, thank you.
SHOP ASSISTANT: What else do you want?
LADY: I want my change.
New Word and expressions 生词和短语
envelope
n. 信封
writing paper
信纸
shop assistant
售货员
size
n. 尺寸，尺码，大小
n. 信纸簿
glue
n. 胶水
chalk
n. 粉笔
change
n. 零钱，找给的钱
您要一本吗？
Lesson 61
重感冒
Listen to the tape then answer this question. What is good news for Jimmy?
MR. WILLIAMS: Where's Jimmy?
MRS. WILLIAMS: He's in bed.
MR. WILLIAMS: What's the matter
with him?
MRS. WILLIAMS: He feels ill.
MR. WILLIAMS: He looks ill.
MRS. WILLIAMS: We must call the doctor.
MR. WILLIAMS: Yes, we must.
MR. WILLIAMS: Can you remember
the doctor's telephone
number?
MRS. WILLIAMS: Yes.
It's 09754.
DOCTOR: Open your mouth, Jimmy.
Show me your tongue.
Say, "Ah'.
MR. WILLIAMS: What's the matter with
him, doctor?
DOCTOR: He has a bad cold,
Mr. Williams,
so he must stay in bed
for a week.
MRS. WILLIAMS: That's good new for
Jimmy.
DOCTOR: Good news?
Why?
MR. WILLIAMS: Because he doesn't like
school!
New Word and expressions 生词和短语
feel
v. 感觉
look
v. 看（起来）
must
modal verb 必须
call
v. 叫，请
doctor
n. 医生
telephone
n. 电话
remember
v. 记得，记住
mouth
n. 嘴
tongue
n. 舌头
cold
n. 感冒
news
n. 消息
看看你的舌头。说“啊——”
因此他必须卧床一周。
Lesson 63
Thank you, doctor.
谢谢你，医生
Listen to the tape then answer this question. Who else is in bed today? Why?
DOCTOR: How's Jimmy today?
MRS. WILLIAMAS: Better. Thank you,
Doctor.
DOCTOR: Can I see him please,
Mrs. Williams?
MRS. WILLIAMAS: Certainly, doctor.
Come upstairs.
DOCTOR: You look very well,
Jimmy. You are better
now, but you mustn't
get up yet. You must
stay in bed for another
two days.
DOCTOR: The boy mustn't
go to school yet,
Mr. Williams.
And he mustn't
eat rich food.
MRS. WILLIAMAS: Does he have a
temperature, doctor?
DOCTOR: No, he doesn't.
MRS. WILLIAMAS: Must he stay in bed?
DOCTOR: Yes.
He must remain in bed
for another two days.
He can get up
for about two hours
each day, but you must
keep the room warm.
DOCTOR: Where's Mr. Williams
this evening?
MRS. WILLIAMAS: He's in bed, doctor.
Can you see him please?
He has a bad cold, too!
New Word and expressions 生词和短语
better
certainly
get up
起床
yet
rich
food
n. 食物
remain
v. 保持，继续
你现在好些了，但你还不应该起
床。你必须再卧床两天。
威廉斯夫人，而且不能吃油腻
的食物。
他每天可以起来两个小时，
但您必须保持房间温暖。
您能看看他吗？
他也得了重感冒！
Lesson 65
Not a baby
不是一个孩子
Listen to the tape then answer this question. Does Jill take the key to the front door?
FATHER: What are you going to do
this evening. Jill?
JILL: I'm going to meet some friends.
FATHER: You mustn't come home late.
You must be home at half past
ten.
JILL: I can't get home so early, Dad!
JILL: Can I have the key
to the front door please?
FATHER: No, you can't.
MOTHER: Jill's eighteen years old, Tom.
She's not a baby.
Give her the key.
She always comes home early.
FATHER: Oh, all right!
FATHER: Here you are.
But you mustn't come home
after a quarter past eleven.
Do you hear?
JILL: Thanks, Mum.
MOTHER: That's all right.
Goodbye.
Enjoy yourself!
JILL: We always enjoy ourselves, Mum.
Bye-bye.
New Word and expressions 生词和短语
n. 爸（儿语）
key
n. 钥匙
baby
n. 婴儿
hear
v. 听见
enjoy
v. 玩得快活
yourself
rpon.你自己
ourselves
pron.我们自己
mum
n. 妈妈
。把钥匙给她吧。她总早早回家的。
见了吗？
Lesson 67
The weekend
周末
Listen to the tape then answer this question. What are the Johnsons going to do at the weekend?
MRS.JOHNSON: Hello.
Where you at the butcher's?
MRS.WILLIAMS:Yes. I was.
Were you at butcher's, too?
MRS.JOHNSON: No, I wasn't.
I was at the greengrocer's.
How's Jimmy today?
MRS.WILLIAMS:He's very well, thank you.
MRS.JOHNSON: Was he absent from school
last week?
MRS.WILLIAMS:Yes, he was.
He was absent on Monday,
Tuesday,
Wednesday and Tuesday.
How are you all keeping?
MRS.JOHNSON: Very well, thank you.
We're going to spend
three days in the country.
We're going to stay at my
mother's for the weekend.
MRS.WILLIAMS:Friday, Saturday and Sunday
in the country!
Aren't you lucky!
New Word and expressions 生词和短语
greengrocer
n. 蔬菜水果零售商
absent
Monday
n. 星期一
Tuesday
n. 星期二
Wednesday
n. 星期三
Thursday
n. 星期四
keep
v. （身体健康）处于（状况）
spend
v. 度过
weekend
n. 周末
Friday
n. 星期五
Saturday
n. 星期六
Sunday
n. 星期日
country
n. 乡村
lucky
您也在肉店里吗？
我在蔬菜水果店里。
吉米今天怎么样？
星期二、星期三和星期四没
去上学。你们身体都好吗？
乡下去三三，在我母亲家度
周末。
过！你们真幸运啊！
Lesson 69
The car race
汽车比赛
Listen to the tape then answer this question. Which car was the winner in 1995?
There is a car race near our town every year. In 1995, there was a very big race.
There were hundreds of people there. My wife and I were at the race. Our friends Julie and Jack were there, too. You can see us in the crowd. We are standing on the left.
There were twenty cars in the race. There were English cars, French cares, German cars. Italian cars. American cars and Japanese cars.
It was an exciting finish. The winner was Billy Stewart. He was in car number fifteen. Five other cars were just behind him.
On the way home, my wife said to me, 'Don't drive so quickly! You're not Billy Stewart!'
New Word and expressions 生词和短语
year
n. 年
race
n. 比赛
town
n. 城填
crowd
n. 人群
stand
v. 站立
exciting
just
finish
n. 结尾，结束
winner
n. 获胜者
behind
prep.在……之后
way
n. 路途
在我们镇子附近每年都有一场汽车比赛。1995年举行了一次盛大的比赛。
许许多多人都去了赛场。我和我的妻子也去了。我们的朋友朱莉和杰克也去了。你可以在人群中看到我们。我们站在左面。
参加比赛的有20辆汽车。有英国、法国、德国、意大利和日本的汽车。
比赛的结尾是激动人心的。获胜者是比利.斯图尔特。他在第15号车里，其他5辆汽车跟在他后面。
在回家的途中，我妻子对我说：“别开得这样快！你可不是比利.斯图尔特！”
Lesson 71
He's awful!
他讨厌透了！
Listen to the tape then answer this question. How did Pauline answer the telephone at nine o'clock?
JANE: What's Ron Marston like,
Pauline?
PAULINE: He's awful!
He telephoned me four times
Yesterday, and three times
the day before yesterday.
PAULINE: He telephoned the office
yesterday morning and
yesterday afternoon.
My boss answered the telephone.
JANE: What did your boss say to him?
PAULINE: He said, "Pauline is typing
typing letters. She can't
speak to you now!"
PAULINE: Then I arrived home
at six o'clock yesterday
evening. He telephoned again.
But I didn't answer the phone!
JANE: Did he telephone again
last night?
PAULINE: Yes, he did.
He telephoned at nine o'clock.
JANE: What did you say to him?
PAULINE: I said, 'This is Pauline's
mother. Please don't telephone
my daughter again!'
JANE: Did he telephone again?
PAULINE: No, he didn't!
New Word and expressions 生词和短语
awful
telephone
v. & n. 打电话；电话
time
n. 次（数）
v. 接（电话）
last
phone
n. 电话（=telephone）
again
say (said/sed/)
v. 说
简：波淋，朗.马顿是怎样一个人？
前天打了3次。
办公室，是我的老板接的。
简：你老板是怎么对他说的？
同你讲话！”
他又打来电话，但我没接。
简：他昨夜里又打电话了吗？
简：你对他怎么说的？
请不要再给我女儿打电话了！”
简：他又打了没有？
Lesson 73
The way to King Street
到国王街的走法
Listen to the tape then answer this question. Why did the man need a phrasebook?
Last week Mrs. Mills went to London. She does not know London very well, and she lost her way.
Suddenly, she saw a man near a bus stop. 'I can ask him the way.' she said to herself.
'Excuse me,' she said. 'Can you tell me the way to King Street, please?'
The man smiled pleasantly. He did not understand English! He spoke German. He was a tourist.
Then he put his hand into pocket, and took out a phrasebook.
He opened the book and found a phrase. He read the phrase slowly. 'I am sorry,' he said. 'I do not speak English.'
New Word and expressions 生词和短语
week
n. 周
London
n. 伦敦
suddenly
bus stop
公共汽车站
smile
v. 微笑
pleasantly
understand (understood)
v. 懂，明白
speak (spoke)
v. 讲，说
hand
n. 手
pocket
n. 衣袋
phrasebook
n. 短语手册，常用语手册
phrase
n. 短语
slowly
上星期米尔斯夫人去了伦敦。她对伦敦不很熟悉，因此迷了路。
突然，她在公共汽车站附近看到一个男人。“我可以向他问路，”她想。
“对不起，您能告诉我到国王街怎么走吗？”她说。
这人友好地笑了笑。他不懂英语！他讲德语。他是个旅游者。
然后他把手伸进了衣袋，掏出了一本常用语手册。
他翻开书找到了一条短语。他缓慢地读着短语。
”很抱歉，“他说，”我不会讲英语。”
Lesson 75
Uncomfortable shoes
不舒适的鞋子
Listen to the tape then answer this question. What's wrong with the fashionable shoes?
LADY: Do you have any shoes
like these?
SHOP ASSISTANT: What size?
SHOP ASSISTANT: I'm sorry.
We don't have any.
LADY: But my sister bought
this pair last month.
SHOP ASSISTANT: Did she buy them here?
LADY: No, she bought them
in the U.S.
SHOP ASSISTANT: We had some shoes like
those a month ago,
but we don't have any
now.
LADY: Can you get a pair for
SHOP ASSISTANT: I'm afraid that I can't.
They were in fashion
last year and the year
before last.
But they're not in
fashion this year.
SHOP ASSISTANT: These shoes are in
fashion now.
LADY: They look very
uncomfortable.
SHOP ASSISTANT: They are very
uncomfortable. But
women always wear
uncomfortable shoes!
New Word and expressions 生词和短语
ago
v. 买
pair
n. 双，对
fashion
n. （服装的）流行式样
uncomfortable
wear
v. 穿着
一双。
但是现在没有了。
而今年已不流行了。
穿不舒适的鞋子！
Lesson 77
Terrible toothache
要命的牙痛
Listen to the tape then answer this question. What time of day is it, do you think? How do you know?
NURSE: Good morning. Mr. Croft.
MR. CROFT: Good morning, nurse.
I was to see the dentist,
NURSE: Do you have an appointment?
MR. CROFT: No, I don't.
NURSE: Is it urgent?
MR. CROFT: Yes, it is.
It's very urgent.
I feel awful.
I have a terrible toothache.
NURSE: Can you come at 10 a.m.
on Monday, April 24th?
MR. CROFT: I must see the dentist now,
nurse.
NURSE: The dentist is very busy
at the moment.
Can you come at 2 p.m.?
MR. CROFT: That's very late.
Can the dentist see me now?
NURSE: I'm afraid that he can't,
Mr. Croft.
Can't you wait till this
afternoon?
MR. CROFT: I can wait, but my toothache
can't!
New Word and expressions 生词和短语
appointment
n. 约会，预约
urgent
till
prep.直到……为止
医生。
牙痛得要命。
钟来行吗？
护士。
您下午两点钟来行吗？
就不能给我看一下吗？
您就不能等到今天下午吗？
可是我的牙痛等不了啊！
Lesson 79
Carol's shopping list
卡罗尔的购物单
Listen to the tape then answer this question. What is Carol not going to buy?
TOM: What are you doing, Carol?
CAROL: I'm making a shopping list, Tom.
TOM: What do we need?
CAROL: We need a lot of thing this week.
CAROL: I must go to the grocer's.
We haven't got much tea or
coffee, and we haven't got any
sugar or jam.
TOM: What about vegetables?
CAROL: I must go to the greengrocer's.
We haven't got many tomatoes,
but we've got a lot of potatoes.
CAROL: I must go to the butcher's, too.
We need some meat.
We haven't got any meat at all.
TOM: Have we got any beer and wine?
And I'm not going to get any!
TOM: I hope that you've got some
money.
CAROL: I haven't got much.
TOM: Well, I haven't got much either!
New Word and expressions 生词和短语
shopping
n. 购物
list
n. 单子
vegetable
n. 蔬菜
need
v. 需要
hope
v. 希望
thing
n. 事情
money
n. 钱
咖啡不多了，糖和果酱也没有了。
番茄不多了，但土豆还有不少。
需要些肉。我们一点肉也没有了。
Lesson 81
Roast beef and potatoes
烤牛肉和土豆
Listen to the tape then answer this question. Why is Carol disappointed?
SAM: Hi, Carol!
Where's Tom?
CAROL: He's upstairs.
He's having a bath.
CAROL: Tom!
TOM: Yes?
CAROL: Sam's here.
TOM: I'm nearly ready.
TOM: Hello, Sam.
Have a cigarette.
SAM: No, thanks, Tom.
TOM: Have a glass of whisky then.
SAM: OK. Thanks.
TOM: Is dinner ready, Carol?
CAROL: It's nearly ready.
We can have dinner at seven
o'clock.
TOM: Sam and I had lunch together
today. We went to a restaurant.
CAROL: What did you have?
TOM: We had roast beef and potatoes.
CAROL: Oh!
TOM: What's the matter, Carol?
CAROL: Well, you're going to have
roast beef and potatoes
again tonight!
New Word and expressions 生词和短语
bath
n. 洗澡
nearly
dinner
n. 正餐，晚餐
roast
我们去了一家饭店。
和土豆了！
Lesson 83
Going on holiday
度假
Listen to the tape then answer this question. Where did Sam go for his holiday this year?
CAROL: Hello, Sam.
Come in.
TOM: Hi, Sam.
We're having lunch.
Do you want to have lunch with
us?
SAM: No, thank you. Tom.
I had at half past twelve.
CAROL: Have a cup of coffee then.
SAM: I've just had a cup, thank you.
I had one after my lunch.
TOM: Let's go into the living room,
Carol.
We can have our coffee there.
CAROL: Excuse the mess, Sam.
This room's very untidy.
We're packing our suitcases.
We're going to leave tomorrow.
Tom and I are going to have a
holiday.
SAM: Aren't you lucky!
TOM: When are you going to have
a holiday, Sam?
SAM: I don't know.
this year.
CAROL: Where did you go?
SAM: I stayed at home!
New Word and expressions 生词和短语
mess
n. 杂乱，凌乱
pack
v. 包装，打包，装箱
suitcase
n. 手提箱
leave
v. 离开
你跟我们一起吃午饭好吗？
我在12点半吃的。
我是在饭后喝的。
卡罗尔。我们可以在那里喝咖啡。
诚心诚意里乱七八糟。我们正在
收拾手提箱。明天我们就要走了。
我和汤姆准备去度假。
Lesson 85
Pairs in the spring
巴黎之春
Listen to the tape then answer this question. At what time of year did Ken visit Paris?
GEORGE: Hello, Ken.
KEN: Hi, George.
GEORGE: Have you just been to the
cinema?
KEN: Yes, I have.
GEORGE: What's on?
KEN: 'Paris in the spring'.
GEORGE: Oh, I've already seen it.
I saw it
on television last year.
It's an old film,
but it's very good.
KEN: Paris is a beautiful city.
GEORGE: I've never been there.
Have you ever been there, Ken?
KEN: Yes, I have.
I was there in April.
GEORGE: Pairs in the spring, eh?
KEN: It was spring,
but the weather was awful.
It rained all the time.
GEORGE: Just like London!
New Word and expressions 生词和短语
Paris
n. 巴黎
cinema
n. 电影院
film
n. 电影
beautiful
city
n. 城市
never
ever
肯：你好，乔治。
肯：是的，我刚去过。
肯：《巴黎之春》。
我是去年在电视上看的。
这是老部片子，但很好。
肯：巴黎是座美丽的城市。
肯：是的，我去过。4月份我在那儿。
肯：是春天，但天气太糟了。
一直在下雨。
Lesson 87
A car crash
车祸
Listen to the tape then answer this question. Can the mechanics repair Mr. Wood's car?
MR. WOOD: Is my car ready yet?
ATTENDANT: I don't know. sir.
What's the number
MR. WOOD: It's is LFZ 312G.
ATTENDANT: When did you bring it to us?
MR. WOOD: I brought it here three
days ago.
ATTENDANT: Ah, yes, I remember now.
MR. WOOD: Have your mechanics
finished yet?
ATTENDANT: No, they're still working on
it. Let's go into the
garage and have a look at it.
ATTENDANT: Isn't that your car?
MR. WOOD: Well, it was my car.
ATTENDANT: Didn't you have a crash?
MR. WOOD: That's right.
I drove it into a lamp-post.
Can your mechanics repair it?
ATTENDANT: Well,
they're trying to repair it,
sir.
But to tell you the truth.
you need a new car!
New Word and expressions 生词和短语
attendant
n. 接待员
bring(brought, brought)
v. 带来，送来
garage
n. 车库，汽车修理厂
crash
n. 碰撞
lamp-post
灯杆
repair
v. 修理
try
v. 努力，设法
您的汽车牌号是多少？
我们到车库去看一下吧。
你们的机械师能修好吗？
不过说实在的，您需要一辆
新车了。
Lesson 89
For sale
待售
Listen to the tape then answer this question. Why couldn't Nigel decide?
NIGEL：Good afternoon.
I believe that this is house is
for sale.
IAN: That's right.
NIGEL：May I have a look at it, please?
IAN: Yes, of course. Come in.
NIGEL：How long have you lived here?
IAN: I've live here for twenty years.
NIGEL：Twenty year!
That's long time.
IAN: Yes, I've been here since 1976.
NIGEL：Then why do you want to sell it?
IAN: Because I've just retired.
I want to buy
a small house in the country.
NIGEL：How much does this house cost?
IAN: $68,500. NIGEL：Well, I like the house. but I can't decide yet. My wife must see it first. IAN: Women always have the last word. New Word and expressions 生词和短语 believe v. 相信，认为 may modal verb （用于请求许可）可以 how long 多长 since prep.自从 why adv. 为什么 sell (sold, sold) v. 卖，出售 because conj.因为 retire v. 退休 cost (cost, cost) v. 花费 pound n. 英镑 worth prep.值……钱 penny n. 便士 参考译文 奈杰尔：下午好。我想这房子是要出售的吧！ 伊 恩: 是的。 奈杰尔：我可以看一看吗？ 伊 恩: 可以，当然可以。请进。 奈杰尔：您在这里住了多长时间？ 伊 恩: 我在这里住了20年了。 奈杰恩：20年！这个时间可不短。 伊 恩: 是啊，从1976年起我就住在这里。 奈杰尔：那么，您为什么要卖掉它呢？ 伊 恩: 因为我刚退休。 我想在乡下买幢小房子。 奈杰尔: 这座房子卖多少钱？ 伊 恩: 68,500英镑。 奈杰尔：我可真是一大笔钱呢！ 伊 恩: 它确确实实值这么多钱。 奈杰尔：啊，我喜欢这房子， 但我还不能决定。 我妻子必须先来看一看。 伊 恩: 女人总是最后说了算的。 Lesson 91 Poor Ian! 可怜的伊恩！ Listen to the tape then answer this question. Who wanted to sell the house? 听录音，然后回答问题。谁想卖房？ CATHERING: Has Ian sold his house yet? JENNY: Yes, he has. He sold it last week. CATHERING: Has he moved to his new house yet? JENNY: No, not yet. He's still here. He's going to move tomorrow. CATHERING: When? Tomorrow afternoon. JENNY: No. Tomorrow afternoon. I'll miss him. He has always been a good neighbour. LIDA: He's a very nice person. We'll all miss him. CATHERING: When will the new people move into this house? JENNY: I think that they'll move in the day after tomorrow. LINDA: Will you see Ian today, Jenny? JENNY: Yes, I will. LINDA: Please give him my regards. CATHERING: Poor Ian! He didn't want to leave this house. JENNY: No, he didn't want to leave. but his wife did! New Word and expressions 生词和短语 still adv. 还，仍旧 move v. 搬家 miss v. 想念，思念 neighbor n. 邻居 person n. 人 people n. 人们 poor adj. 可怜的 参考译文 凯瑟琳：伊恩已指他的房子卖掉了吗？ 詹 尼：是的，卖掉了。他上星期卖掉的。 凯瑟琳：他已经迁进新居了吗？ 詹 尼：不，还没有。他仍在这里。 他打算明天搬家。 凯瑟琳：什么时候？明天上午吗？ 詹 尼：不，明天下午。我会想念他的。 他一直是个好邻居。 琳 达：他是个非常好的人， 我们大学都会想念他的。 凯瑟琳：新住户什么时候搬进这所房子？ 詹 尼：我想他们将会在后天搬进来吧。 琳 达：詹尼，您今天会见到伊恩吗？ 詹 尼：是的，我会见到他。 琳 达：请代我问候他。 凯瑟琳：可怜的伊恩！他本不想离开这幢 房子。 詹 尼：是啊，他是不想离开， 可是他妻子要离开。 Lesson 93 Our new neighbour 我们的新邻居 Listen to the tape then answer this question. Why is Nigel a lucky man? 听录音，然后回答问题。为什么说奈杰尔很幸运？ Nigel is our new next-door neighbour. He's a pilot. He was in the R.A.F. He will fly to New York next month. The month after next he'll fly to Tokyo. At the moment, he's in Madrid. He flew to Spain a week ago. He'll return to London the week after next. He's only forty-one years old, and he has already been to nearly every country in the world. Nigel is a very lucky man. But his wife isn't very lucky. She usually stays at home! New Word and expressions 生词和短语 pilot n. 飞行员 return v. 返回 New York n. 纽约 Tokyo n. 东京 Madrid n. 马德里 fly (flew, flown) v. 飞行 参考译文 奈杰尔是我们新搬来的隔壁邻居。他是个飞行员。 他曾在皇家空军任职。 下个月他将飞往纽约。 再下个月他将飞往东京。 现在他在马德里。他是一星期以前飞到西班牙的。 再下个星期他将返回伦敦。 他只有41岁，但他却过世界上几乎每一个国家。 奈杰尔是个很幸运的人。但他的妻子运气不很好。他总是呆在家里！ Lesson 95 Tickets, please. 请把车票拿出来。 Listen to the tape then answer this question. Why did George and Ken miss the train? 听录音，然后回答问题。为什么乔治和肯误了火车？ GEORGE: Two return tickets to London, please. What time will the next train leave? ATTENDANT: At nineteen minutes past eight. GEORGE: Which platform? ATTENDANT: Platform Two. Over the bridge. KEN: What time will the next train leave? GEORGE: At eight nineteen. KEN: We've got plenty of time. GEORGE: It's only three minutes to eight. KEN: Let's go and have a drink. There's a bar next door to the station. GEORGE: We had better go back to the station now, Ken. PORTER: Tickets, please. GEORGE: We want to catch the eight nineteen to London. PORTER: You've just missed it! GEORGE: What! It's only eight fifteen. PORTER: I'm sorry, sir. That clock's ten minutes slow. GEORGE: When's the next train? PORTER: In five hours' time! New Word and expressions 生词和短语 return n. 往返 train n. 火车 platform n. 站台 plenty n. 大量 bar n. 洒吧 station n. 车站，火车站 porter n. 收票员 catch (caught, caught) v. 赶上 miss v. 错过 参考译文 乔 治：买两张到伦敦的往返票。 下一班火车什么时候开？ 服务员：8点19分。 乔 治：在哪个站台？ 服务员：2号站台。过天桥。 肯：下一班火车什么时候开？ 乔 治：8点19分。 肯：我们时间还很宽裕。 乔 治：现在才7点57分。 肯：让我们去喝点东西吧， 车站旁有一个酒吧。 乔 治：肯，我们现在最好回车站去。 收票员：请把车票拿出来。 乔 治：我们要乘8点19分的车去伦敦。 收票员：你们刚好错过了那班车。 乔 治：什么！现在只有8点15分。 收票员：对不起，先生，那个钟慢了10分钟。 乔 治：下一班车是什么时候？ 收票员：5个小时以后！ Lesson 97 A small blue case 一只蓝色的小箱子 Listen to the tape then answer this question. Does Mr. Hall get his case back? 听录音，然后回答问题。霍尔先生有没有要回他的提箱？ MR. MALL: I left a suitcase on the train to London the other day. ATTENDANT: Can you describe it, sir? MR. MALL: It's a small blue case and it's got a zip. There's a label on the handle with my name and address on it. ATTENDANT: Is this case yours? MR. MALL: No, that's not mine. ATTENDANT: What about this one? This one's got a label. MR. MALL: Let me see it. ATTENDANT: What's your name and address? MR. MALL: David Hall, 83, Bridge Street. ATTENDANT: That's right. D.N. Hall, 83, Bridge Street. ATTENDANT: Three pounds fifty pence, please. MR. MALL: Here you are. ATTENDANT: Thank you. MR. MALL: Key! ATTENDANT: What's matter? MR. MALL: This case doesn't belong to me! You've given me the wrong case! New Word and expressions 生词和短语 leave (left, left) v. 遗留 describe v. 描述 zip n. 拉链 label n. 标签 handle n. 提手，把手 address n. 地址 pence n. penny 的复数形式 belong v. 属于 参考译文 霍尔先生：几天前我把一只手提箱忘在 开往伦敦的火车上了。 服 务 员：先生，您能描述一下它是什么 样子的吗？ 霍尔先生：是只蓝色的小箱子，上面有拉链。 箱把上有一标签， 上面写着我的姓名和住址。 服 务 员：这箱子是您的吗？ 霍尔先生：不，那不是我的。 服 务 员：这只是不是？这只箱子有张标签。 霍尔先生：让我看看。 服 务 员：您的姓名和住址？ 霍尔先生：大卫.霍尔，大桥街83号。 服 务 员：那就对了。D.N.霍尔， 大桥街83号。 服 务 员：请付3英镑50便士。 霍尔先生：给您。 服 务 员：谢谢您。 霍尔先生：嗨！ 服 务 员：怎么回事？ 霍尔先生：这箱子不是我的！您给错了！ Lesson 99 Owl! 啊哟！ Listen to the tape then answer this question. Must Andy go to see the doctor? 听录音，然后回答问题。安迪需要去看医生吗？ ANDY: Ow! LUCY: What's the matter, Andy? ANDY: I slipped and fell downstairs. LUCY: Have you hurt yourself? ANDY: Yes, I have. I think that I've hurt my back. LUCY: Try and stand up. Can you stand up? Here. Let me help you. ANDY: I'm sorry, Lucy. I'm afraid that I can't get up. LUCY: I think that the doctor had better see you. I'll phone Dr. Carter. LUCY: The doctor says that he will come at once. I'm sure that you need an X-ray, Andy. New Word and expressions 生词和短语 own int. 哎哟 slip v. 滑倒，滑了一脚 fall (fell, fallen) v. 落下，跌倒 downstairs adv. 下楼 hurt (hurt, hurt) v. 伤，伤害，疼痛 back n. 背 stand up 起立，站起来 help v. 帮助 at once 立即 sure adj. 一定的，确信的 X-ray n. X光透视 参考译文 安迪：啊哟！ 露西：怎么了，安迪？ 安迪：我滑了一跤，从楼梯上摔下来了。 露西：你摔伤了没有？ 安迪：是啊，摔伤了。我想我把背摔坏了。 露西：试试站起来。你能站起来吗？ 来，让我帮你。 安迪：对不起，露西，恐怕我站不起来。 露西：我想最好请医生来给你看一下。 我去给卡特医生打电话。 露西：医生说他马上就来。安迪， 我看你需要做一次X光透视。 Lesson 101 A card from Jimmy 吉米的明信片 Listen to the tape then answer this question. Does Grandmother seem pleased to get a card from Jimmy? Why/Why not? 听录音，然后回答问题。收到吉米寄来的一张明信片，祖母是否显得高兴？为什么/为什么不高兴？ GRANDMOTHER: Read Jimmy's card to me please, penny. PENNY: 'I have just arrive in Scotland and I'm staying at a Youth Hostel.' GRANDMOTHER: Eh? PENNY: He say he's just arrived in Scotland. He says he's staying at a Youth Hostel. You know he's a member of the Y.H.A. GRANDMOTHER: The what? PENNY: The Y.H.A., Mum. The Youth Hostels Association. GRANDMOTHER: What else does he say? PENNY: 'I'll write a letter soon. I hope you all well.' GRANDMOTHER: What? Speak up. Penny. I'm afraid I can't hear you PENNY: He say he'll write a letter soon. He hopes we are all well. 'Love, Jimmy.' GRANDMOTHER: Is that all? He doesn't say very much, does he? PENNY: He can't write very much on a card, Mum. New Word and expressions 生词和短语 Scotland n. 苏格兰（英国） card n. 明信片 youth n. 青年 hostel n. 招待所，旅馆 association n. 协会 soon adv. 不久 write (wrote, written) v. 写 参考译文 祖母：请把吉米的明信片念给我听听，彭妮。 彭妮：“我刚到苏格兰，我现住在一家青年 招待所。” 祖母：什么？ 彭妮：他说他刚到苏格兰。他说他住在一家 青年招待所。你知道，他是“青招协” 的一个成员。 祖母：什么？ 彭妮：“青招协”，妈妈。青年招待所协会。 祖母：他还说了些什么？ 彭妮：“我很快会写信的。 祝你们大家身体都好。” 祖母：什么？彭妮，大声一点。 我可听不见你念的。 彭妮：他说他很快会写信的。他祝我们大家 身体好。“谨此问候，吉米。” 祖母：就这些吗？他没写许多，是吗？ 彭妮：在明信片上他写不了很多，妈妈。 Lesson 103 The French test 法语考试 Listen to the tape then answer this question. How long did the exam last? 听录音，然后回答问题。 考试持续了多长时间？ GARY: How was the exam, Richard? RICHARD: Not too bad. I think I passed in English and Mathematics. The questions were very easy. How about you, Gary? GARY: The English and Maths papers weren't easy enough for me. I hope I haven't failed. RICHARD: I think I failed the French paper. I could answer sixteen of the question. They were very easy. But I couldn't answer the rest. They were too difficult for me. GARY: French test are awful, aren't they? RICHARD: I hate them. I'm sure I've got a low mark. GARY: Oh, cheer up! perhaps we didn't to do badly. The guy next to me Wrote his name at the top of the paper. RICHARD: Yes? GARY: Then he sat there and looked at it for three hours! He didn't write a word! New Word and expressions 生词和短语 exam n. 考试 pass v. 及格，通过 mathematics (maths是缩写) n. 数学 question n. 问题 easy adj. 容易的 enough adv. 足够地 paper n. 考卷 fail v. 未极格，失败 answer v. 回答 mark n. 分数 rest n. 其他的东西 difficult adj. 困难的 hate v. 讨厌 low adj. 低的 cheer v. 振作，振奋 guy n. 家伙，人 top n. 上方，顶部 参考译文 加 里：考试考得怎样，理查德？ 理查德：不算太坏，我想我的英语和数学 及格了。题目很容易。加里， 你怎么样？ 加 里：英语和数学试题对我来说不很容易。 我希望别不及格。 理查德：我想我的法语及不了格，我能回答 其中的16道题。这些题很容易。 但我回答不出其作的题。那些题对 我来说太难了。 加 里：法语太可怕了，你说呢？ 理查德：我讨厌法语。我的法语成绩肯定 很低。 加 里：啊，别灰心！或许我们考得还不太 糟。坐在我旁边的那个人只在试卷 顶端写自己的名字。 理查德：是吗？ 加 里：然后他就坐在那里，对着考卷看了3 个小时，一个字也没写！ Lesson 105 Full of mistakes 错误百出 Listen to the tape then answer this question. What was Sandra's present? 听录音，然后回答问题。给桑德拉的礼物是什么？ THE BOSS：Where's Sandra, Bob? I want her. BOB: Do you want to speak to her? THE BOSS：Yes, I do. I want her to come to my office. Tell her to come at once. SANDRA: Did you want to see me? THE BOSS：Ah, yes, Sandra. How do you spell "intelligent'? Can you tell me? SANDRA: I-N-T-E-L-L-I-G-E-N-T. THE BOSS：That's right. You've typed it with only one 'L'. This letter's full of mistakes. I want you to type it again. SANDRA: Yes, I'll do that. I'm sorry about that. THE BOSS：And here's a little present for you. SANDRA: What's it? THE BOSS：It's a dictionary. I hope it'll help you. New Word and expressions 生词和短语 spell v. 拼写 intelligent adj. 聪明的，有智慧的 mistake n. 错误 present n. 礼物 dictionary n. 词典 参考译文 老 板：鲍勃，桑德拉在哪儿？我要找她。 鲍 勃：您要同她谈话吗？ 老 板：是的，我要她到我的办公室来。 叫她马上就来。 桑德拉：您找我吗？ 老 板：啊，是的，桑德拉。"intelligent" 怎样拼写？你能告诉我吗？ 桑德拉：I-N-T-E-L-L-I-G-E-N-T。 老 板：对的。但你只打了1个“L”。 这封信里错误百出。我要你重打一遍。 桑德拉：是，我重打。对此我感到很抱歉。 老 板：这里有一件小礼物送你。 桑德拉：是什么？ 老 板：是本词典。我希望它能对你有所帮助。 Lesson 107 It's too small. 太小了。 Listen to the tape then answer this question. What kind of dress does the lady want? 听录音，然后回答问题。 这位女士想要什么样的服装？ ASSISTANT: Do you like this dress, madam? LADY: I like the colour very much. It's lovely dress, but it's too small for me. ASSISTANT: What about this one? It's lovely dress. It's very smart. Short skirts are in fashion now. Would you like to try it? LADY: All right. LADY: I'm afraid this green dress it too small for me as well. It's smaller than the blue one. LADY: I don't like the colour either. It doesn't suit me at all. I think the blue dress is prettier. LADY: Could you show me another blue dress? I want a dress like that one, but it must be my size. ASSISTANT: I'm afraid I haven't got a larger dress. This is the largest dress in the shop. New Word and expressions 生词和短语 madam n. 夫人，女士（对妇女的尊称） smart adj. 漂亮的 as well 同样 suit v. 适于 pretty adj. 漂亮的 参考译文 店员：夫人，您喜欢这件衣服吗？ 女士：我很喜欢这颜色。这件漂亮的衣服， 可是对我来说太小了。 店员：这件怎么样？这是件漂亮的衣服， 它很时髦。短裙现在很流行。 您要试一试吗？ 女士：好吧。 店员：恐怕这件绿色的我穿着也太小了。 它比那件蓝色的还要小。 女士：我也不喜欢这种颜色。这颜色我穿 根本不合适。我认为那件蓝色的更 漂亮些。 女士：您能再给我看一件蓝色的吗？ 我想一件和那件一样的， 但必须是我的尺寸。 店员：恐怕没有更大的了。 这是店里最大一件。 Lesson 109 A good idea 好主意 Listen to the tape then answer this question. What does Jane have with her coffee? 听录音，然后回答问题。喝咖啡时简吃了什么？ CHARLOTTE: Shall I make some coffee, Jane? JANE: That's a good idea, Charlotte. CHARLOTTE: It's ready. Do you want any milk? JANE: Just a little, please. CHARLOTTE: What about some sugar? Two teaspoonfuls? JANE: No, less than that. One and a half teaspoonfuls, please. That's enough for me. JANE: That was very nice. CHARLOTTE: Would you like some more? JANE: Yes, please. JANE: I'd like a cigarette, too. May I have one? CHARLOTTE: Of course. I think there are a few in that box. JANE: I'm afraid it's empty. CHARLOTTE: What a pity! JANE: It doesn't matter. CHARLOTTE: Have a biscuit instead. Eat more and smoke less! JANE: That's very good advice! New Word and expressions 生词和短语 idea n. 主意 a little 少许（用于不可数名词之前） teaspoonful n. 一满茶匙 less adj. (little 的比较级)较少的，更小的 a few 几个（用于可数名词之前） pity n. 遗憾 instead adv. 代替 advice n. 建议，忠告 参考译文 夏洛特：我来煮点咖啡好吗，简？ 简：这是个好主意，夏洛特。 夏洛特：咖啡好了，你要放点奶吗？ 简：请稍加一点。 夏洛特：加些糖怎么样？两茶匙行吗？ 简：不，再少一些。请放一勺儿半。 那对我已足够了。 简：太好了。 夏洛特：你再来点吗？ 简：好的，请再来一点。 简：我还想抽枝烟。可以给我一枝吗？ 夏洛特：当然可以。我想那个盒子里有一些。 简：恐怕盒子是空的。 夏洛特：真遗憾！ 简：没关系。 夏洛特：那就吃块饼干吧。多吃点，少抽点！ 简：这是极好的忠告啊！ Lesson 111 The most expensive model 最昂贵的型号 Listen to the tape then answer this question. Can Mr. Frith buy the television on instalments? How does it work? 听录音，然后回答问题。弗里斯先生可以用分期付款方式购买电视机吗？如何操作呢？ MR. FRITH: I like television very much. How much does it cost? ASSISTANT: It's the most expensive model in the shop. It costs five hundred pounds. MR. FRITH: That's too expensive for us. We can't afford all that money. ASSISTANT: This model's less expensive than that one. It's only three hundred pounds. But, of course, it's not as good as the expensive one. MR. FRITH: I don't like the model. The other model's more expensive, but it's worth the money. MR. FRITH: Can we buy it on instalments? ASSISTANT: Of course. You can pay a deposit of thirty pounds, and then fourteen pounds a month for three years. MR. FRITH: Do you like it, dear? MRS. FRITH:I certainly do, but I don't like the price. You always want the best, but we can't afford it. Sometimes you think you're a millionaire! MR. FRITH: Millionaires don't buy things on instalments! New Word and expressions 生词和短语 model n. 型号 afford v. 付得起（钱） deposit n. 预付定金 instalment n. 分期付款 price n. 价格 millionaire n. 百万富翁 参考译文 弗里斯先生：我非常喜欢这台电视机。 请问它多少钱？ 店 员：这是店里最贵的型号。 它的售价是500英镑。 弗里斯夫人：这对我们来说是太贵了。 我们花不起那么多钱。 店 员：这种型号比那种要便宜些。 它只要300英镑。但是， 它当然没有价钱高那种好。 弗里斯先生：我不喜欢这种型号。 那种型号价格是贵一些， 但它值得那么多钱。 弗里斯先生：我们可以用分期付款的方式] 购买吗？ 店 员：当然可以。您可以先付30英镑 定金，然后每月14镑,3年付清。 弗里斯先生：你喜欢吗，亲爱的？ 弗里斯夫人：我当然喜欢，但是我不喜欢这 个价钱。你总是要买最好的， 可我们买不起，有时候你认 为自己是个百万富翁！ 弗里斯先生：百万富翁是不会分期付款 买东西的！ Lesson 113 Small change 零钱 Listen to the tape then answer this question. Who has got some change? 听录音，然后回答问题。谁有零钱？ CONDUCTOR: Fares, please! MAN: Trafalgar Square, please. CONDUCTOR: I'm sorry, sir. I can't change a ten-pound note. Haven't you got any small change? MAN: I've got no small change, I am afraid. CONDUCTOR: I'll ask some of the passengers. CONDUCTOR: Have you any small change, sir? 1st PASSENGER: I'm sorry. I've got none. 2nd PASSENGER: I haven't got any either. CONDUCTOR: Can you change this ten-pound note, madam? 3rd PASSENGER: I'm afraid I can't. 4th PASSENGER: Neither can I. CONDUCTOR: I'm very sorry, sir. You must get off the bus. None of our passengers can change this note. They're all millionaires! TWO TRAMPS: Except us. 1sth TRAMP: I've got some small change. 2nd TRAMP: So have I. New Word and expressions 生词和短语 conductor n. 售票员 fare n. 车费, 车票 change v. 兑换（钱） note n. 纸币 passenger n. 乘客 none pron.没有任何东西 neither adv. 也不 get off 下车 tramp n. 游浪汉 except prep.除……外 参考译文 售票员： 请买票！ 男 子： 请买一张到特拉法加广场的票。 售票员： 对不起，我找不开10英镑的钞票。 您没有零钱吗？ 男 子： 恐怕我没有零钱。 售票员： 我来问问其他乘客。 售票员： 先生，您有零钱吗？ 乘 客1： 对不起，我没有。 乘 客2： 我也没有。 售票员： 夫人，您能把这10英镑的钞票 换开吗？ 乘 客3： 恐怕不能。 乘 客4： 我也不能。 售票员： 非常抱歉，先生。您必须下车。 我们的乘客中没人能换开这张 钞票。 他们都是百万富翁！ 二流浪汉：我们俩除外。 流浪汉1： 我有零钱。 流浪汉2： 我也有。 Lesson 115 Knock, knock! 敲敲门！ Listen to the tape then answer this question. What does Jim have to drink? 听录音，然后回答问题。吉姆只能喝什么饮料？ HELEN: Isn't there anyone at home? JIM: I'll knock again, Helen. Everything's very quiet. I'm sure there's no one at home. HELEN: But that's impossible. Carol and Tom invited us to lunch. Look through the window. HELEN: Can you see anything? JIM: Nothing at all. HELEN: Let's try the back door. JIM: Look! Everyone's in the garden. CAROL: Hello, Helen. Hello, Jim. TOM: Everybody wants to have lunch in the garden. It's nice and warm out here. CAROL: Come and have something to drink. JIM: Thanks, Carol. May I have a glass of beer please? CAROL: Beer? There's none left. You can have some lemonade. JIM: Lemonade! TOM: Don't believe her, Jim. She's only joking. Have some beer! New Word and expressions 生词和短语 anyone pron.（用地疑问句，否定句）任何人 knock v. 敲，打 everything pron.一切事情 quiet adj. 宁静的，安静的 impossible adj. 不可能的 invite v. 邀请 anything pron.任何东西 nothing pron.什么也没有 lemonade n. 柠檬水 joke v. 开玩笑 参考译文 海 伦：家里没有人吗？ 吉 姆：海伦，我再敲一次。毫无动静，肯定 家里没有人。 海 伦：但这是不可能的。卡罗尔和汤姆请 我们来吃午饭。从窗子往里看看。 海 伦：你能看见什么吗？ 吉 姆：什么也看不见。 海 伦：让我们到后门去试试。 吉 姆：瞧！大家都在花园里。 卡罗尔：你好，海伦。你好，吉姆。 汤 姆：大家都想在花园里吃午饭。 这外面挺暖和。 卡罗尔：来喝点什么。 汤 姆：谢谢，卡罗尔。给我一杯啤酒好吗？ 卡罗尔：啤酒？一点都不剩了。 你可以喝点柠檬水。 吉 姆：柠檬水！ 汤 姆：吉姆，别信她的。她只是在开玩笑。 喝点啤酒吧！ Lesson 117 Tommy's breakfast 汤米的早餐 Listen to the tape then answer this question. What does she mean by 'change in the last sentence? 听录音，然后回答问题。最后一名话中的“change" 是什么意思？ When my husband was going into the dining room this morning, he dropped some coins on the floor. There were coins everywhere. We looked for them, but we could not find them all. While we were having breakfast, our little boy, Tommy, found two small coins on the floor. He put them both into his mouth. We both tried to get the coins, but it was too late. Tommy had already swallowed them! Late that morning, when I was doing the housework, My husband phoned me from the office. 'How's Tommy?' he asked. 'I don't know,' I answered, 'Tommy's been to the toilet three times this morning, but I haven't had any change yet!' New Word and expressions 生词和短语 dinning room 饭厅 coin n. 硬币 mouth n. 嘴 swallow v. 吞下 later adv. 后来 toilet n. 厕所，盥洗室 参考译文 今天早晨我丈夫走进饭厅时，把一些硬币掉在地上了。 到处都是硬币。我们虽然找了，但没有把它们全部找到。 正当我们吃早饭时，我们的小男孩汤米在地上找到两枚小硬币。 他把这两枚硬币全都放进嘴里。我们俩都试图把这两枚硬币拿出来，但太迟了。汤米已经把硬币咽了下去！ 那天下午的晚些时候，当我正做家务时，我丈夫从办公室打来电话。 “汤米怎么样？”他问。“我不知道”，我回答说，“今天上午汤米去了3次厕所了，但我还没看到硬币！” Lesson 119 A true story 一个真实的故事 Listen to the tape then answer this question. Who called out to the thieves in the dark? 听录音，然后回答问题。谁在暗处对窃贼喊了一声？ Do you like stories? I want to tell you a true story. It happened to a friend of mine a year ago. While my friend, George, was reading in bed, two thieves climbed into his kitchen. After they had entered the house, they went into the dining room. It was very dark, so they turned on a torch. Suddenly, they heard a voice behind them. "What's up? What's up?" someone called. The thieves dropped the torch and ran away as quickly as they could. George heard the noise and came downstairs quickly. He turned on the light, but he couldn't see anyone. The thieves had already gone. But George's parrot, Henry, was still there. "What's up, George?" the called. 'Nothing, Henry,' George said and smiled. 'Go back to sleep.' New Word and expressions 生词和短语 story n. 故事 happen v. 发生 thief n. 贼 enter v. 进入 dark adj. 黑暗的 torch n. 手电筒 voice n. （说话的）声音 parrot n. 鹦鹉 参考译文 你喜欢听故事吗？我要告诉你一个真实的故事。这是一年前发生在我的一个朋友身上的故事。 当我的朋友乔治在床上看书时，两个小偷爬进了他的厨房。 他们进到屋里后，走进了饭厅。饭厅很暗，于是他们打开了手电筒。 突然他们听到身后有声音。“什么事？什么事？”有人叫着。小偷扔下了手电筒，飞快地逃走了。 乔治听到了响声，迅速地下了楼。 他开了灯，但不见一个人。小偷逃走了。 但时乔治的鹦鹉亨利仍在那里。“什么事，乔治？”它叫着。“没事，亨利。”乔治笑着说，“接着睡觉吧。” Lesson 121 The man in a hat 戴帽子的男士 Listen to the tape then answer this question. Why didn't Caroline recognize the customer straight away? 听录音，然后回答问题。为什么卡罗琳没有马上认出那位顾客？ CUSTOMER: I bought two expensive dictionaries here half and hour ago, but I forgot to take them with me. MANAGER: Who served you, sir? CUSTOMER: The lady who is standing behind the counter. MANAGER: Which books did you buy? CUSTOMER: The books which are on the counter. MANAGER: Did you serve this gentleman half an hour ago, Caroline? He says he's the man who bought these books. CUSTOMER: I can't remember. The man who I served was wearing a hat. MANAGER: Have you got a hat, sir? CUSTOMER: Yes, I have. MANAGER: Would you put it on, please? CUSTOMER: All right. MANAGER: Is this the man that you served, Caroline? CUSTOMER: Yes. I recognize him now. New Word and expressions 生词和短语 customer n. 顾客 forget (forgot, forgotten) v. 忘记 manager n. 经理 serve v. 照应，服务，接待 counter n. 柜台 recognize v. 认出 参考译文 顾 客：半小时以前我在这里买了两本很 贵的辞典，但是我忘了拿走。 经 理：是谁接待您的，先生？ 顾 客：站在柜台后面的那位女士。 经 理：您买的是两本什么书？ 顾 客：就是柜台上的那两本。 经 理：卡罗琳，半小时前你接待过这位先生 吗？他说他就是买这两本书的人。 卡罗琳：我记不起来了。我接待的那个人戴着 一顶帽子。 经 理：先生，您有帽子吗？ 顾 客：有的，我有帽子。 经 理：请您把帽子戴上好吗？ 顾 客：好吧。 经 理：卡罗琳， 这就是你接待过的那个人吗？ 卡罗琳：是他。我现在认出他来了。 Lesson 123 A trip to Australia 澳大利亚之行 Listen to the tape then answer this question. Who is the man with the beard? 听录音，然后回答问题。那个长着络腮胡子的人是谁？ MIKE: Look, Scott. This is a photograph I took during my trip to Australia. SCOTT: Let me see it, Mike. SCOTT: This is a good photograph. Who are these people? MIKE: They're people I met during the trip. MIKE: That's the ship we travelled on. SCOTT: What a beautiful ship! SCOTT: Who's this? MIKE: That's the man I told you about. Remember? SCOTT: Ah yes. The one who offered you a job in Australia. MIKE: That's right. SCOTT: Who's this? MIKE: Guess! SCOTT: It's not you, is it? MIKE: That's right. MIKE: I grew a beard during the trip. but I shaved it off when I came home. SCOTT: Why did you shave it off? MIKE: My wife didn't like it! New Word and expressions 生词和短语 during prep.在……期间 trip n. 旅行 travel v. 旅行 offer v. 提供 job n. 工作 guess v. 猜 grow (grew, grown) v. 长，让……生长 beard n. （下巴上的）胡子，络腮胡子 参考译文 迈 克：看，这是我到澳大利来旅行时 拍的一张照片。 斯科特：让我看看，迈克。 斯科特：这是一张很好的照片。这些人是谁。 迈 克：他们是我旅行时认识的人。 迈 克：这是我们所乘的那条船。 斯科特：多漂亮的船啊！ 斯科特：这是谁？ 迈 克：这就是我跟你说过的那个人。 还记得吗？ 斯科特：啊，记得。就是在澳大利亚给你工作 的那个人。 迈 克：对。 斯科特：这是谁？ 迈 克：你猜！ 斯科特：这不是你，对吗？ 迈 克：不，是我。 迈 克：我在旅行时留了胡子， 但我回到家时就把它刮了。 斯科特：你为什么把它刮了？ 迈 克：我妻子不喜欢！ Lesson 125 Tea for two 两个人一起喝茶 Listen to the tape then answer this question. Does Susan have tea by herself? 听录音，然后回答问题。苏珊是一个人喝茶吗？ SUSAN: Can't you come in and have tea now, Peter? PETER: Not yet. I must water the garden first. SUSAN: Do you have to water it now? PETER: I'm afraid I must. Look at it! It's terribly dry. SUSAN: What a nuisance! PETER: Last summer it was very dry, too. Don't you remember? I had to water it every day. SUSAN: Well, I'll have tea by myself. SUSAN: That was quick! Have you finished already? PETER: Yes. Look out of the window. SUSAN: It's raining! That means You don't need to water the garden. PERTR: That was a pleasant surprise. It means I can have tea, instead. New Word and expressions 生词和短语 water v. 浇水 terribly adv. 非常 dry adj. 干燥的，干的 nuisance n. 讨厌的东西或人 mean (meant, meant) v. 意味着，意思是 surprise n. 惊奇，意外的事 参考译文 苏珊：彼得，你现在能进来喝茶吗？ 彼得：还不能。我得先给花园浇水。 苏珊：你一定得现在浇吗？ 彼得：恐怕我得现在浇。你看看，干得厉害。 苏珊：真讨厌！ 彼得：去年夏天也是干得很。 你记得了吗？我不得不每天浇水。 苏珊：好吧，我一个喝茶了。 苏珊：好快啊！你已经浇完了？ 彼得：是的。你看看窗外。 苏珊：下雨了，这就是就是说， 你不必给花园浇水了。 彼得：这是意想不能的好事。 这意味着我反倒可以喝茶了。 Lesson 127 A famous actress 著名的女演员 Listen to the tape then answer this question. Who is only twenty-nine, and why is it so unclear? 听录音，然后回答问题。谁只有29岁？为什么这件事如此含糊不清？ KATE: Can you recognize that woman, Liz? LIZ: I think I can, Kate. It must be Karen Marsh, the actress. KATE: I though so. Who's that beside her? LIZ: That must be Conrad Reeves. KATE: Conrad Reeves, the actor? It's can't be. Let me have another look. I think you're right! Isn't he her third husband? LIZ: No. He must be her fourth or fifth. KATE: Doesn't Karen Marsh look old! LIZ: She does, doesn't she! I read she's twenty-nine, but she must be at least forty. KATE: I'm sure she is. LIZ: She was a famous actress When I was still at school. KATE: That was a long time ago, wasn't it? LIZ: Not that long ago! I'm not more than twenty-nine myself. New Word and expressions 生词和短语 famous adj. 著名的 actress n. 女演员 at least 至少 actor n. 男演员 read (read, read) v. 通过阅读得知 参考译文 凯特：莉兹，你能认出那个女人吗？ 莉兹：我想我认得出来，凯特。那一定是女 演员卡.马会。 凯特：我也这样想。她旁边的那个人是谁？ 莉兹：一定是康拉德.里弗斯。 凯特：康拉德.里弗斯，那个男演员吗？ 不可能是。让我再看一看。 我想你是对的。他不是她的第3个 丈夫吗？ 莉兹：不，他一定是她的第4个或第5个丈夫。 凯特：卡伦看上去不显老嘛！ 莉兹：是的，谁说不是呢！我从报上看到她 是29岁，但她一定至少有40岁了。 凯特：我肯定她有40岁了。 莉兹：当我还是学生时，她就是个著名的 演员了。 凯特：那是好久以前的事了。是吗？ 莉兹：不，没有那么久。我自己现在还没 29岁呢。 Lesson 129 Seventy miles an hour 时速70英里 Listen to the tape then answer this question. What does Ann advise her husband to do next time? 听录音，然后回答问题。安建议她的丈夫下次做什么？ ANN: Look, Gary! That policeman's waving to you. He wants you to stop. POLICEMAN: Where do you think you are? On a race track? You must have been driving at seventy miles an hour. GARY: I can't have been. POLICEMAN: I was doing eighty when I overtook you. POLICEMAN: Didn't you see the speed limit? GARY: I'm afraid I didn't, officer. I must have been dreaming. ANN: He wasn't dreaming, officer. I was telling him to drive slowly. GARY: That's why I didn't see the sign. POLICEMAN: Let me see your driving licence. POLICEMAN: I won't charge you this time. But you'd better not do it again! GARY: Thank you. I'll certainly be more careful. ANN: I told you to drive slowly, Gary. GARY: You always tell me to drive slowly, darling. ANN: Well, next time you'd better take my advice! New Word and expressions 生词和短语 wave v. 招手 track n. 跑道 mile n. 英里 overtake (overtook, overtaken) v. 从后面超越，超车 speed limit 限速 dream v. 做梦，思想不集中 sign n. 标记，牌子 driving licence 驾驶执照 charge v. 罚款 darling n. 亲爱的（用作表示称呼） 参考译文 安：瞧，加里！那个警察正朝你挥手呢。 他要你停下来。 警察：你认为你现在是在哪儿？ 在赛车道上吗？你刚才一定是以每小时 70英里的速度开车。 加里：我不会开得那么快的。 警察：我是以第小时80英里的速度赶上你的。 警察：难道你没看见限速牌吗？ 加里：恐怕我没有看见，警官。 我一定思想开小差了。 安：警官，他思想没有开小差。 我刚才正告诉他开慢点。 安里：所以我才没看见那牌子。 警察：让我看一看你的驾驶执照。 警察：这次我就不罚你款了。但你最好不要再 开得这样快。 加里：谢谢您。我以后一定会多加注意。 安：加里，我刚才叫你开慢点吧。 加里：你总是叫我开慢点，亲爱的。 安：好啦，下次你最好还是听从我的劝告！ Lesson 131 Don't be so sure! 别那么肯定！ Listen to the tape then answer this question. What's the problem about deciding on a holiday? 听录音，然后回答问题。决定如何度假有什么为难的地方？ MARTIN: Where are you going to spend your holidays this year, Gary? GARY: We may go abroad. I'm not sure. My wife wants go to Egypt. I'd like to there, too. We can't make up our minds. MARTIN: Will you travel by sea or air? GARY: We may travel by sea. MARTIN: It's cheaper, isn't it? GARY: It may be cheaper. but it takes a long time. MARTIN: I'm sure you'll enjoy yourselves. GART: Don't be so sure. We might not go anywhere. My wife always worries too much. Who's going to look after the dog? Who's going to look after the house? Who's going to look after the garden? We have this problem every year. in the end, we stay at home and look after everything! New Word and expressions 生词和短语 Egypt n. 埃及 abroad adv. 国外 worry v. 担忧 参考译文 马丁：加里，今年你们打算去哪里度假？ 加里：我们可能到国外去，但我不敢肯定。 我妻子想到埃及去，我也想去那儿。 我们还拿不定主意。 马丁：你们乘船去，还是乘飞机去？ 加里：我们可能乘船去。 马丁：这更便宜些，是吗？ 加里：可能是便宜些，但花的时间长。 马丁：我肯定你们一定会玩得很痛快。 加里：别那么肯定。我们可能哪里也去不成。 我妻子总是担心那的。谁来照看狗啦， 谁来看管房子啦，谁来照料花园啦， 我们每年都碰到这类问题。末了， 我们呆在家里来照看一切。 Lesson 133 Sensational news! 爆炸性新闻！ Listen to the tape then answer this question. What reason did Karen Marsh give for wanting to retire? 听录音，然后回答问题。卡伦.马什说她为什么想要退休？ REPORTER: Have you just made a new film, Miss Marsh? MISS MARSH: Yes, I have. REPORTER: Are you going to make a another? MISS MARSH: No, I'm not. I'm going to retire. I feel very tired. I don't want to make another film for a long time. KATE: Let's buy a newspaper, Liz. Listen to this! 'Karen Marsh: Sensational News! By our reporter, Alan Jones. Karen Marsh arrived at London Airport today. She was wearing a blue dress and a mink coat. She told me she had just made a new film. she said she was not going to make another. She said she was going to retire. She told reporters she felt very tired and didn't want to make another film for a long time.' LIZ: I wonder why! New Word and expressions 生词和短语 reporter n. 记者 sensational adj. 爆炸性的，耸人听闻的 mink coat 貂皮大衣 参考译文 记 者：您刚拍完一部新电影吗， 马什小姐？ 马什小姐：是的，我刚拍完。 记 者：您准备再拍一部吗？ 马什小姐：不，我不准备拍了。 我准备退休了。我感觉累得很。 我早就不想再拍片子了。 凯 特：我们买份报纸吧。莉兹。 你听这段：“卡伦.马什： 爆炸性新闻！由本报记者艾伦. 琼斯报导。卡伦.马什今天到达 伦敦机场。她穿着一身蓝色的 套装和一件貂皮大衣。她告诉 我她刚拍完一部新片子。她不 准备再拍电影了。她说她准备 退休。她告诉记者她感到很疲 劳，早就不想再拍电影了。 莉 兹：我很想知道为什么。 Lesson 135 The latest report 最新消息 Listen to the tape then answer this question. Is Karen Marsh going to retire, do you think? 听录音，然后回答问题。你认为卡伦.马什会退休吗？ REPORTER: Are you really going to retire, miss Marsh? MISS MARSH: I may. I can't make up my mind. I will have to ask my future husband. He won't let me make another film. REPORTER: Your future husband, Miss Marsh? MISS MARSH: Yes. Let me introduce him to you. His name is Carlos. We're going to get married next week. KATE: Look, Liz! Here's another report about Karen Marsh. Listen: 'Karen Marsh: The latest. At her London Hotel today Miss Marsh told reporters she might retire. She said she couldn't make up her mind. She said she would have to ask her future husband. She said her future husband would not let her make another film. Then she introduced us to Carlos and told us they would get married next week'. LIZ: That's sensational news, isn't it, Kate? KATE: It certainly is. He'll be her sixth husband! New Word and expressions 生词和短语 future n. 未来的 get married 结婚 hotel n. 饭店 latest adj. 最新的 introduce v. 介绍 参考译文 记 者：马什小姐，您真的准备退休吗？ 马什小姐：有可能退。我还拿不定主意。 我得问一下我的未婚夫。他不会 再让我拍电影了。 记 者：您的未婚夫，马什小姐？ 马什小姐：是的，让我把他给你们介绍一下。 他叫卡洛斯。下星期我们就要 结婚了。 凯 特：看啊，莉兹！这又有一篇关于卡 伦.马会的报道。你听，“卡伦. 马什：最新消息。今天在伦敦旅 馆，马什小姐告诉记者她可能要 退休。她说她还拿不定主意。她 说她得问问她的未婚夫。她说她 的未婚夫不会再让她拍电影。 然后她把我们介绍给卡洛斯， 并告诉我们说他们下星期结婚。” 莉 兹：凯特，这真是条轰动的消息， 是不是？ 凯 特：当然啦。他将是她的第6个丈夫！ Lesson 137 A pleasant dream 美好的梦 Listen to the tape then answer this question. What would Julie like to do, if she had the money? 听录音，然后回答问题。如果朱莉有那笔钱，她想做什么呢？ JULIE: Are you doing the football pools, Brain? BRIAN: Yes, I've nearly finished, Julie. Julie. I'm sure we'll win something this week. JULIE: You always say that, but we never win anything! What will you do if you win a lot of money? BRIAN: If I win a lot of money I'll buy you a mink coat. JULIE: I don't want a mink coat! I want to see the world. BRIAN: All right. If we win a lot of money We'll travel round the world and we'll stay at the best hotels. Then we'll return home and buy a big house in the country. We'll have a beautiful garden and … JULIE: But if we spend all that money we'll be poor again. What'll we do then? BRIAN: If we spend all the money we'll try and win the football pools again. JULIE: It's a pleasant dream but everything depends on 'if'! New Word and expressions 生词和短语 football n. 足球 pool n. 赌注 win (won, won) v. 赢 world n. 世界 poor adj. 贫穷的 depend v. 依靠（on） 参考译文 朱 莉：布赖恩，你正在下足球赛的赌注吗？ 布赖恩：是的。我这就做完了。朱莉。 我敢肯定这星期我们会赢一点的。 朱 莉：你老是那样说，但是我们从来没 赢过！要是你赢了许多钱，你打算 做什么呢？ 布赖恩：要是我赢了许多钱，我给你买件 貂皮大衣。 朱 莉：我不要貂皮大衣。我要去见风世面。 布赖恩：好吧。要是我们赢了很多钱，我们 就去周游世界，并且往最好的旅馆。 然后我们返回家园，在乡下买幢大 房子。我们将有一个漂亮的花园和 …… 朱 莉：但是如果我们把所有钱都花光了， 我们又会变穷的。那时我们怎么 办呢？ 布赖恩：如果我们花光了所有钱，我们设法 在足球赛赌注上再赢一次。 朱 莉：这是个美好的梦，但一切都取决于 “如果”！ Lesson 139 Is that you, John? 是你吗，约翰？ Listen to the tape then answer this question. Which John Smith does Graham Turner think he is talking to? 听录音，然后回答问题。格雷厄姆.特纳以为他在和哪一个约翰.史密斯通话？ GRAHAM TURNER: Is that you, John? JOHN SMITH: Yes, speaking. GRAHAM TURNER: Tell Mary we'll be late for dinner this evening. JOHN SMITH: I'm afraid I don't understand. GRAHAM TURNER: Hasn't Mary told you? She invited Charlotte and me to dinner this evening. I said I would be at your house at six o'clock, but the boss want me to do some extra work. I'll have to stay at the office. I don't know when I'll finish. Oh, and by the way, my wife wants to know if Mary needs any help. JOHN SMITH: I don't know what you're talking about. GRAHAM TURNER: That is John Smith, isn't it? JOHN SMITH: Yes, I'm John Smith. GRAHAM TURNER: You are John Smith, the engineer, aren't you? JOHN SMITH: That's right. GRAHAM TURNER: You work for the Overseas Engineering Company, don't you? JOHN SMITH: No, I don't I'm John Smith the telephone engineer and I'm repairing your telephone line. New Word and expressions 生词和短语 extra adj. 额外的 overseas adj. 海外的，国外的 engineering n. 工程 company n. 公司 line n. 线路 参考译文 格雷厄姆.特纳：是你吗，约翰？ 约 翰.史 密斯：是我，请讲。 格雷厄姆.特纳：你告诉玛丽，今晚吃饭将晚到一会儿。 约 翰.史 密斯：恐怕我还不明白您的意思。 格雷厄姆.特纳：玛丽没有告诉你吗？ 她邀请我和夏洛特今晚去 吃饭。我说过我6点到你家， 但老板要我加班。我不得 不留在办公室，不知道什 么时候才能结束。喔， 顺便问一问，我妻子想知 道玛丽是否需要帮忙。 约 翰.史 密斯：我不知道您在说些什么。 格雷厄姆.特纳：你是约翰.史密斯，对吗？ 约 翰.史密 斯： 是的，我是约翰.史密斯。 格雷厄姆.特纳：你是工程师约翰.史密斯， 对吗？ 约 翰.史 密斯：对。 格雷厄姆.特纳：你在海外工程公司上班， 是吗？ 约 翰.史 密斯：不，不是。我是电话工程 师约翰.史密斯，我正在 修理您的电话线。 Lesson 141 Sally's first train ride 萨莉第一交乘火车旅行 Listen to the tape then answer this question. Why was the mother embarrassed? 听录音，然后回答问题。为什么母亲感到尴尬？ Last week, my four-year-old daughter, Sally, was invited to a children's party. I decided to take her by train. Sally was very excited because she had never travelled on a train before. She sat near the window and asked questions about everything she saw. Suddenly, a middle-age lady got on the train and sat opposite Sally. 'Hello, little girl,' she said. Sally did not answer, but looked at her curiously. The lady was dressed in a blue coat and a large, funny hat. After the train had left the station, the lady opened her handbag and took to her power compact. She then began to make up her face. 'Why are you doing that?' Sally asked. 'To make myself beautiful,' the lady answered. She put away her compact and smiled kindly. 'But you are still ugly,' Sally said. Sally was amused, but I was very embarrassed! New Word and expressions 生词和短语 excited adj. 兴奋的 get on 登上 middle-aged adj. 中年的 opposite prep.在……对面 curiously adv.好奇地 funny adj. 可笑的，滑稽的 powder n. 香粉 compact n. 带镜的化妆盒 kindly adv. 和蔼地 ugly adj. 丑陋的 amused adj. 有趣的 smile v. 微笑 embarrassed adj. 尴尬 参考译文 上周，我4岁的女儿萨莉被邀请去参加一个儿童聚会。我决定带她乘火车去。萨莉非常激动，因为她从未乘过火车。她靠车窗坐着，对她所看到的一切都要问个明白。突然，一个中年妇女上了火车，坐在萨莉的对面。“你好，小姑娘，”她说。萨莉没回答，却好奇地看着她。那位妇女穿着一件蓝色的大衣，戴着一顶大而滑稽的帽子。火车开出车站后，那位妇女找开了手提包，拿出了粉盒。然后她开始打扮起来。“你为什么要那样做呢？”萨莉问。“为了把自己打扮漂亮啊，”那位妇女答道。她放好了粉盒，慈祥地微笑着。“可是你仍然难看呀，”萨莉说。萨莉感到很有趣，而我却很尴尬。 Lesson 143 A walk through the woods 林中散步 Listen to the tape then answer this question. What was so funny about the words on the sign? 听录音，然后回答问题。牌子上的字有什么可笑的地方？ I live in a very old town which is surrounded by beautiful woods. It is a famous beauty spot. On Sundays, hundreds of people come from the city to see our town and to walk through the woods. Visitors have been asked to keep the woods clean and tidy. Litter baskets have been placed under the trees, but people still throw their rubbish everywhere. Last Wednesday, I went for a walk in the woods. What I saw made me very sad. I counted seven old cars and three old refrigerators. The little baskets were empty and the ground was covered with pieces of paper, cigarette ends, old tyres, empty bottles and rusty tins. Among the rubbish, I found a sign which said, 'Anyone who leaves litter in these woods will be prosecuted!' New Word and expressions 生词和短语 surround v. 包围 wood n. 树林 beauty spot 风景点 hundred n. 百 city n. 城市 through prep.穿过 visitor n. 参观者，游客，来访者 tidy adj. 整齐的 litter n. 杂乱的东西 litter basket 废物筐 place v. 放 throw( threw; thrown) v. 扔，抛 rubbish n. 垃圾 count v. 数，点 cover v. 覆盖 piece n. 碎片 tyre n. 轮胎 rusty adj. 生锈的 among prep.在……之间 prosecute v. 依法处置 参考译文 我住在一个由美丽的树林环绕的古老的小镇上。这是一个著名的风景胜地。每适星期天，有许许多人从城里来观赏我们的小镇，并在树林中散步。游客已被告知要保持树林的整洁。树下都已设置了废物筐，但是人们仍到处扔垃圾。上星期三我到树林里去散步。我所见到的一切使我非常难过。我数了一下，有7辆旧汽车和3上旧冰箱。废物筐是空的，而满地都是纸片、烟头、旧轮胎，空瓶子和生锈的空罐头盒。在垃圾堆中我发现了一块牌子，上面写着：“凡在此树林里丢弃垃圾者，将依法处置。 Plum Board http://www.plumsite.cn/bbs倾情奉献 Lesson 1 A private conversation 私人谈话 First listen and then answer the question. 听录音，然后回答以下问题。 Why did the writer complain to the people behind him? Last week I went to the theatre. I had a very good seat. The play was very interesting. I did not enjoy it. A young man and a young woman were sitting behind me. They were talking loudly. I got very angry. I could not hear the actors. I turned round. I looked at the man and the woman angrily. They did not pay any attention. In the end, I could not bear it. I turned round again. 'I can't hear a word!' I said angrily. 'It's none of your business,' the young man said rudely. 'This is a private conversation!' New words and expressions 生词和短语 private adj. 私人的 conversation n. 谈话 theatre n. 剧场，戏院 seat n. 座位 play n. 戏 loudly adv. 大声地 angry adj. 生气的 angrily adv. 生气地 attention n. 注意 bear v. 容忍 business n. 事 rudely adv. 无礼地，粗鲁地 参考译文 上星期我去看戏。我的座位很好，戏很有意思，但我却无法欣赏。一青年男子与一青年女子坐在我的身后，大声地说着话。我非常生气，因为我听不见演员在说什么。我回过头去怒视着那一男一女，他们却毫不理会。最后，我忍不住了，又一次回过头去，生气地说：“我一个字也听不见了！” “不关你的事，”那男的毫不客气地说，“这是私人间的谈话！” Lesson 2 Breakfast or lunch? 早餐还是午餐？ First listen and then answer the question. 听录音，然后回答以下问题。 Why was the writer's aunt surprised? It was Sunday. I never get up early on Sundays. I sometimes stay in bed until lunchtime. Last Sunday I got up very late. I looked out of the window. It was dark outside. 'What a day!' I thought. 'It's raining again.' Just then, the telephone rang. It was my aunt Lucy. 'I've just arrived by train,' she said. 'I'm coming to see you.' 'But I'm still having breakfast,' I said. 'What are you doing?' she asked. 'I'm having breakfast,' I repeated. 'Dear me,' she said. 'Do you always get up so late? It's one o'clock!' New words and expressions 生词和短语 until prep. 直到 outside adv. 外面 ring v. （铃、电话等）响 aunt n. 姑，姨，婶，舅母 repeat v. 重复 参考译文 那是个星期天，而在星期天我是从来不早起的，有时我要一直躺到吃午饭的时候。上个星期天，我起得很晚。我望望窗外，外面一片昏暗。“鬼天气！”我想，“又下雨了。”正在这时，电话铃响了。是我姑母露西打来的。“我刚下火车，”她说，“我这就来看你。” “但我还在吃早饭，”我说。 “你在干什么？”她问道。 “我正在吃早饭，”我又说了一遍。 “天啊，”她说，“你总是起得这么晚吗？现在已经1点钟了！” Lesson 3 Please send me a card 请给我寄一张明信片 First listen and then answer the question. 听录音，然后回答以下问题。 How many cards did the writer send? Postcards always spoil my holidays. Last summer, I went to Italy. I visited museums and sat in public gardens. A friendly waiter taught me a few words of Italian. Then he lent me a book. I read a few lines, but I did not understand a word. Everyday I thought about postcards. My holidays passed quickly, but I did not send cards to my friends. On the last day I made a big decision. I got up early and bought thirty-seven cards. I spent the whole day in my room, but I did not write a single card! New words and expressions 生词和短语 send v. 寄，送 postcard n. 明信片 spoil v. 使索然无味，损坏 museum n. 博物馆 public adj. 公共的 friendly adj. 友好的 waiter n. 服务员，招待员 lend v. 借给 decision n. 决定 whole adj. 整个的 single adj. 唯一的，单一的 参考译文 明信片总搅得我假日不得安宁。去年夏天，我去了意大利。我参观了博物馆，还去了公园。一位好客的服务员教了我几句意大利语，之后还借给我一本书。我读了几行，但一个字也不懂。我每天都想着明信片的事。假期过得真快，可我还没有给我的朋友们寄过一张明信片。到了最后一天，我作出了一项重大决定。我早早起了床，买来了37张明信片。我在房间里关了整整一天。然而竟连一张明信片也没写成！ Lesson 4 An exciting trip 激动人心的旅行 First listen and then answer the question. 听录音，然后回答以下问题。 Why is Tim finding this trip exciting? I have just received a letter from my brother, Tim. He is in Australia. He has been there for six months. Tim is an engineer. He is working for a big firm and he has already visited a great number of different places in Australia. He has just bought an Australian car and has gone to Alice springs, a small town in the centre of Australia. He will soon visit Darwin. From there, he will fly to Perth. My brother has never been abroad before, so he is fending this trip very exciting. New words and expressions 生词和短语 exciting adj. 令人兴奋的 receive v. 接受，收到 firm n. 商行，公司 different adj. 不同的 centre n. 中心 abroad adv. 在国外 参考译文 我刚刚收到弟弟蒂姆的来信，他正在澳大利亚。他在那儿已经住了6个月了。蒂姆是个工程师，正在一家大公司工作，并且已经去过澳大利亚的不少地方了。他刚买了一辆澳大利亚小汽车，现在去了澳大利亚中部的小镇艾利斯斯普林斯。他不久还将到达达尔文去，从那里，他再飞往珀斯。我弟弟以前从未出过国，因此，他觉得这次旅行非常激动人心。 Lesson 5 No wrong numbers 无错号之虞 First listen and then answer the question. 听录音，然后回答以下问题。 What does 'No wrong numbers' mean? Mr.James Scott has a garage in Silbury and now he has just bought another garage in Pinhurst. Pinhurst is only five miles from Silbury, but Mr. Scott cannot get a telephone for his new garage, so he has just bought twelve pigeons. Yesterday, a pigeon carried the first message from Pinhurst to Silbury. The bird covered the distance in three minutes. Up to now, Mr.Scott has sent a great many requests for spare parts and other urgent messages from one garage to the other. In this way, he has begun his own private 'telephone' service. New words and expressions 生词和短语 pigeon n. 鸽子 message n. 信息 cover v. 越过 distance n. 距离 request n. 要求，请求 spare part 备件 service n. 业务，服务 参考译文 詹姆斯.斯科特先生在锡尔伯里有一个汽车修理部，现在他刚在平赫斯特买了另一个汽车修理部。平赫特离锡尔伯里只有5英里，但詹姆斯.斯科特先生未能为他新的汽车修理部搞到一部电话机，所以他买了只鸽子。昨天，一只鸽子把第一封信从平赫特带到锡尔伯里。这只鸟只用了3分钟就飞完了全程。到目前为止，斯科特先生从一个汽车修理部向另一个发送了大量索取备件的信件和其他紧急函件。就这样，他开始自己的私人“电话”业务。 Lesson 6 Percy Buttons 珀西.巴顿斯 First listen and then answer the question. 听录音，然后回答以下问题。 Who is Percy Buttons? I have just moved to a house in Bridge Street. Yesterday a beggar knocked at my door. He asked me for a meal and a glass of beer. In return for this, the beggar stood on his head and sang songs. I gave him a meal. He ate the food and drank the beer. Then he put a piece of cheese in his pocket and went away. Later a neighbour told me about him. Everybody knows him. His name is Percy Buttons. He calls at every house in the street once a month and always asks for a meal and a glass of beer. New words and expressions 生词和短语 beggar n. 乞丐 food n. 食物 pocket n. 衣服口袋 call v. 拜访，光顾 参考译文 我刚刚搬进了大桥街的一所房子。昨天一个乞丐来敲我的门，问我要一顿饭和一杯啤酒。作为回报，那乞丐头顶地倒立起来，嘴里还唱着歌。我给了他一顿饭。他把食物吃完，又喝了酒。然后把一块乳酪装进衣袋里走了。后来，一位邻居告诉了我他的情况。大家都认识他，他叫珀西.巴顿斯。他每月对这条街上的每户人家光顾一次，总是请求给他一顿饭和一杯啤酒。 Lesson 7 Too late 为时太晚 First listen and then answer the question. 听录音，然后回答以下问题。 Did the detectives save the diamonds? The plane was late and detectives were waiting at the airport all morning. They were expecting a valuable parcel of diamonds from South Africa. A few hours earlier, someone had told the police that thieves would try to steal the diamonds. When the plane arrived, some of the detectives were waiting inside the main building while others were waiting on the airfield. Two men took the parcel off the plane and carried it into the Customs House. While two detectives were keeping guard at the door, two others opened the parcel. To their surprise, the precious parcel was full of stones and sand! New words and expressions 生词和短语 detective n. 侦探 airport n. 机场 expect v. 期待，等待 valuable adj. 贵重的 parcel n. 包裹 diamond n. 钻石 steal v. 偷 main adj. 主要的 airfield n. 飞机起落的场地 guard n. 警戒，守卫 precious adj. 珍贵的 stone n. 石子 sand n. 沙子 参考译文 飞机误点了，侦探们在机场等了整整一上午。他们正期待从南非来的一个装着钻石的贵重包裹。数小时以前，有人向警方报告，说有人企图偷走这些钻石。当飞机到达时，一些侦探等候在主楼内，另一些侦探则守候在停机坪上。有两个人把包裹拿下飞机，进了海关。这时两个侦探把住门口，另外两个侦探打开了包裹。令他们吃惊的是，那珍贵的包裹里面装的全是石头和沙子！ Lesson 8 The best and the worst 最好的和最差的 First listen and then answer the question. 听录音，然后回答以下问题。 Why is Joe's garden the most beautiful one in the town? Joe Sanders has the most beautiful garden in our town. Nearly everybody enters for 'The Nicest Garden Competition' each year, but Joe wins every time. Bill Frith's garden is larger than Joe's. Bill works harder than Joe and grows more flowers and vegetables, but Joe's garden is more interesting. He has made neat paths and has built a wooden bridge over a pool. I like gardens too, but I do not like hard work. Every year I enter for the garden competition too, and I always win a little prize for the worst garden in the town! New words and expressions 生词和短语 competition n. 比赛，竞赛 neat adj. 整齐的，整洁的 path n. 小路，小径 wooden adj. 木头的 pool n. 水池 参考译文 乔.桑德斯拥有我们镇上最漂亮的花园。几乎每个人都参加每年举办的“最佳花园竞赛”，而每次都是乔获胜。比尔.弗里斯的花园比乔的花园大，他比乔也更为勤奋，种植的花卉和蔬菜也更多，但乔的花园更富有情趣。他修筑了一条条整洁的小路，并在一个池塘上架了一座小木桥。我也喜欢花园，但我却不愿意辛勤劳动。每年的花园竞赛我也参加，但总因是镇上最劣的花园而获得一个小奖！ Lesson 9 A cold welcome 冷遇 First listen and then answer the question. 听录音，然后回答以下问题。 What does 'a cold welcome' refer to? On Wednesday evening, we went to the Town Hall. It was the last day of the year and a large crowd of people had gathered under the Town Hall clock. It would strike twelve in twenty minutes' time. Fifteen minutes passed and then, at five to twelve, the clock stopped. The big minute hand did not move. We waited and waited, but nothing happened. Suddenly someone shouted. 'It's two minutes past twelve! The clock has stopped!' I looked at my watch. It was true. The big clock refused to welcome the New Year. At that moment, everybody began to laugh and sing. New words and expressions 生词和短语 welcome n. 欢迎；v. 欢迎 crowd n. 人群 gather v. 聚集 hand n. （表或机器的）指针 shout v. 喊叫 refuse v. 拒绝 laugh v. 笑 参考译文 星期三的晚上，我们去了市政厅。 那是一年的最后一天，一大群人聚集在市政厅的大钟下面。再过20分钟，大钟将敲响12下。15分钟过去了，而就在11点55分时，大钟停了。那根巨大的分针不动了。 我们等啊等啊，可情况没有变化。突然有人喊道：“已经12点零2分了！那钟已经停了！”我看了一下我的手表，果真如此。那座大钟不愿意迎接新年。此时，大家已经笑了起来，同时唱起了歌。 Lesson 10 Not for jazz 不适于演奏爵士乐 First listen and then answer the question. 听录音，然后回答以下问题。 What happened to the clavichord? We have an old musical instrument. It is called a clavichord. It was made in Germany in 1681. Our clavichord is kept in the living room. It has belonged to our family for a long time. The instrument was bought by my grandfather many years ago. Recently it was damaged by a visitor. She tried to play jazz on it! She struck the keys too hard and two of the strings were broken. My father was shocked. Now we are not allowed to touch it. It is being repaired by a friend of my father's. New words and expressions 生词和短语 jazz n. 爵士音乐 musical adj. 音乐的 instrument n. 乐器 clavichord n. 古钢琴 recently adv. 最近 damage v. 损坏 key n. 琴键 string n. （乐器的）弦 shock v. 使不悦或生气，震惊 allow v. 允许，让 touch v. 触摸 参考译文 我家有件古乐器，被称作古钢琴，是1681年德国造的。我们的这架古钢琴存放在起居室里。我们家有这件乐器已经很久了， 是我祖父在很多年以前买的。可它最近被一个客人弄坏了，因为她用它来弹奏爵士乐。她在击琴键时用力过猛，损坏了两根琴弦。我父亲大为吃惊，不许我们再动它。父亲的一个朋友正在修理这件乐器。 Lesson 11 One good turn deserves another 礼尚往来 First listen and then answer the question. 听录音，然后回答以下问题。 Who paid for Tony's dinner? I was having dinner at a restaurant when Tony Steele came in. Tony worked in a lawyer's office years ago, but he is now working at a bank. He gets a good salary, but he always borrows money from his friends and never pays it back. Tony saw me and came and sat at the same table. He has never borrowed money from me. While he was eating, I asked him to lend me twenty pounds. To my surprise, he gave me the money immediately. 'I have never borrowed any money from you,' Tony said, 'so now you can pay for my dinner!' New words and expressions 生词和短语 turn n. 行为，举止 deserve v. 应得到，值得 lawyer n. 律师 bank n. 银行 salary n. 工资 immediately adv. 立刻 参考译文 我正在一家饭馆吃饭，托尼.斯蒂尔走了进来。托尼曾在一家律师事务所工作，而现在正在一家银行上班。他的薪水很高，但他却总是向朋友借钱，并且从来不还。托尼看见了我，就走过来和我坐到一张桌子前。他从未向我借过钱。当他吃饭时，我提出向他借20英镑。令我惊奇的是，他立刻把钱给了我。“我还从未向你借过钱，”托尼说道，“所以现在你可以替我付饭钱了！” Lesson 12 Goodbye and good luck 再见，一路顺风 First listen and then answer the question. 听录音，然后回答以下问题。 Where is Captain Alison going and how? Our neighbour, Captain Charles Alison, will sail from Portsmouth tomorrow. We'll meet him at the harbour early in the morning. He will be in his small boat, Topsail. Topsail is a famous little boat. It has sailed across the Atlantic many times. Captain Alison will set out at eight o'clock, so we'll have plenty of time. We'll see his boat and then we'll say goodbye to him. He will be away for two months. We are very proud of him. He will take part in an important race across the Atlantic. New words and expressions 生词和短语 luck n. 运气，幸运 captain n. 船长 sail v. 航行 harbour n. 港口 proud adj. 自豪 important adj. 重要的 参考译文 我们的邻居查尔斯.艾利森船长明天就要从朴次茅斯启航了。明天一大早我们将在码头为他送行。他将乘坐他的“涛波赛”号小艇。“涛波赛”号是艘有名的小艇，它已经多次横渡大西洋。艾利森船长将于8点钟启航，因此我们有充裕的时间。我们将参观他的船，然后和他告别。他要离开两个月，我们真为他感到自豪，他将参加一次重大的横渡大西洋的比赛。 Lesson 13 The Greenwood Boys 绿林少年 First listen and then answer the question. 听录音，然后回答以下问题。 Why will the police have a difficult time? The Greenwood Boys are a group of pop singers. At present, they are visiting all parts of the country. They will be arriving here tomorrow. They will be coming by train and most of the young people in the town will be meeting them at the station. Tomorrow evening they will be singing at the Workers' Club. The Greenwood Boys will be staying for five days. During this time, they will give five performances. As usual, the police will have a difficult time. They will be trying to keep order. It is always the same on these occasions. New words and expressions 生词和短语 group n. 小组，团体 pop singer 流行歌手 club n. 俱乐部 performance n. 演出 occasion n. 场合 参考译文 “绿林少年”是一个流行歌曲演唱团。目前他们正在全国各地巡回演出，明天就要到达此地。他们将乘火车来，镇上的大部分青年人将到车站迎接他们。明晚他们将在工人俱乐部演出。“绿林少年”准备在此逗留5天。在此期间，他们将演出5场。同往常一样，警察的日子将不好过，他们将设法维持秩序。每逢这种场合，情况都是这样。 Lesson 14 Do you speak English? 你会讲英语吗？ First listen and then answer the question. 听录音，然后回答以下问题。 Did the young man speak English? I had an amusing experience last year. After I had left a small village in the south of France, I drove on to the next town. On the way, a young man waved to me. I stopped and he asked me for a lift. As soon as he had got into the car, I said good morning to him in French and he replied in the same language. Apart from a few words, I do not know any French at all. Neither of us spoke during the journey. I had nearly reached the town, when the young man suddenly said, very slowly, "Do you speak English?' As I soon learnt, he was English himself!' New words and expressions 生词和短语 amusing adj. 好笑的，有趣的 experience n. 经历 wave v. 招手 lift n. 搭便车 reply v. 回答 language n. 语言 journey n. 旅行 参考译文 去年我有过一次有趣的经历。在离开法国南部的一个小村庄后，我继续驶往下一个城镇。途中，一个青年人向我招手。我把车停下，他向我提出要求搭车。他一上车，我就用法语向他问早上好，他也同样用法语回答我。除了个别几个单词外，我根本不会法语。旅途中我们谁也没讲话。就要到达那个镇时，那青年突然开了口，慢慢地说道：“你会讲英语吗？” 我很快了解到，他自己就是个英国人！ Lesson 15 Good news 佳音 First listen and then answer the question. 听录音，然后回答以下问题。 What was the good news? The secretary told me that Mr. Harmsworth would see me. I felt very nervous when I went into his office. He did not look up from his desk when I entered. After I had sat down, he said that business was very bad. He told me that the firm could not afford to pay such large salaries. Twenty people had already left. I knew that my turn had come. 'Mr.Harmsworth,' I said in a weak voice. 'Don't interrupt,' he said. Then he smiled and told me I would receive an extra thousand pounds a year! New words and expressions 生词和短语 secretary n. 秘书 nervous adj. 精神紧张的 afford v. 负担得起 weak adj. 弱的 interrupt v. 插话，打断 参考译文 秘书告诉我说哈姆斯沃斯先生要见我。我走进他的办公室，感到非常紧张。我进去的时候，他连头也没抬。待我坐下后，他说生意非常不景气。他还告诉我，公司支付不起这么庞大的工资开支，有20个人已经离去。我知道这次该轮到我了。 “哈姆斯沃斯先生，”我无力地说。 “不要打断我的话，”他说。 然后他微笑了一下告诉我说，我每年将得到1,000 英镑的额外收入。 Lesson 16 A polite request 彬彬有礼的要求 First listen and then answer the question. 听录音，然后回答以下问题。 What was the polite request? If you park your car in the wrong place, a traffic policeman will soon find it. You will be very lucky if he lets you go without a ticket. However, this does not always happen. Traffic police are sometimes very polite. During a holiday in Sweden, I found this note on my car: 'sir, we welcome you to our city. This is a "No Parking" area. You will enjoy your stay here if you pay attention to our street signs. This note is only a reminder.' If you receive a request like this, you cannot fail to obey it! New words and expressions 生词和短语 park v. 停放（汽车） traffic n. 交通 ticket) n. 交通违规罚款单 note n. 便条 area n. 地段 sign n. 指示牌 reminder n. 提示 fail v. 无视，忘记 obey v. 服从 参考译文 一旦你把汽车停错了地方，交通警很快就会发现。如果他没给你罚单就放你走了，算你走运。然而，情况并不都是这样，交通警有时也很客气。有一次在瑞典度假，我发现我的车上有这样一个字条：“先生，欢迎您光临我们的城市。此处是‘禁止停车’区。如果您对我们街上的标牌稍加注意，您在此会过得很愉快的。谨此提请注意。”如果你收到这样的恳求，你是不会不遵照执行的！ Lesson 17 Always young 青春常驻 First listen and then answer the question. 听录音，然后回答以下问题。 Why doesn't Aunt Jennifer tell anyone how old she is? My aunt Jennifer is an actress. She must be at least thirty-five years old. In spite of this, she often appears on the stage as a young girl. Jennifer will have to take part in a new play soon. This time, she will be a girl of seventeen. In the play, she must appear in a bright red dress and long black stockings. Last year in another play, she had to wear short socks and a bright, orange-coloured dress. If anyone ever asks her how old she is, she always answers, 'Darling, it must be terrible to be grown up!' New words and expressions 生词和短语 appear v. 登场，扮演 stage n. 舞台 bright adj. 鲜艳的 stocking n. （女用）长筒袜 sock n. 短袜 参考译文 我的姑姑詹妮弗是位演员，她至少也有35岁了。尽管如此，她却常在舞台上扮演小姑娘。詹妮弗很快又要参加一个新剧的演出。这一次，她将扮演一个17岁的少女。演出时她必须穿一条鲜红色的裙子和黑色的长筒袜。去年在演另一个剧时，她不得不穿短袜和一件鲜艳的橘红色的衣服。一旦有人问起她有多大年纪，她总是回答：“亲爱的，长成大人真可怕啊！” Lesson 18 He often does this! 他经常干这种事！ First listen and then answer the question. 听录音，然后回答以下问题。 What had happened to the writer's bag? After I had had lunch at a village pub, I looked for my bag. I had left it on a chair beside the door and now it wasn't there! As I was looking for it, the landlord came in. 'Did you have a good meal?" he asked. 'Yes, thank you,' I answered, 'but I can't pay the bill. I haven't got my bag.' The landlord smiled and immediately went out. In a few minutes he returned with my bag and gave it back to me. 'I'm very sorry,' he said. 'My dog had taken in into the garden. He often does this!' New words and expressions 生词和短语 pub n. 小酒店 landlord n. 店主 bill n. 帐单 参考译文 我在一家乡村小酒店吃过午饭后，就找我的提包。我曾把它放在门边的椅子上，可这会儿不见了！当我正在寻找时，酒店老板走了进来。 “您吃得好吗？”他问。 “很好，谢谢。”我回答，“但我付不了帐，我的提包没有了。” 酒店老板笑了笑，马上走了出去。一会儿工夫他拿着我的提包回来了，把它还给了我。 “实在抱歉，”他说，“我的狗把它弄到花园里去了，他常干这种事！” Lesson 19 Sold out 票已售完 First listen and then answer the question. 听录音，然后回答以下问题。 When will the writer see the play? 'The play may begin at any moment,' I said. 'It may have begun already,' Susan answered. I hurried to the ticket office. 'May I have two tickets please?' I asked. 'I'm sorry, we've sold out,' the girl said. 'What a pity!' Susan exclaimed. Just then, a man hurried to the ticket office. 'Can I return these two tickets?' he asked. 'Certainly,' the girl said. I went back to the ticket office at once. 'Could I have those two tickets please?' I asked. 'Certainly,' the girl said, 'but they're for next Wednesday's performance. Do you still want them?' 'I might as well have them,' I said sadly. New words and expressions 生词和短语 hurry v. 匆忙 ticket office 售票处 pity n. 令人遗憾的事 exclaim v. 大声说 return v. 退回 sadly adv. 悲哀地，丧气地 参考译文 “剧马上就要开演了，”我说。 “也许已经开演了呢，”苏珊回答说。 我匆匆赶到售票处，问：“我可以买两张票吗？” “对不起，票已售完。”那位姑娘说。 “真可惜！”苏珊大声说。 正在这时，一个男子匆匆奔向售票处。 “我可以退掉这两张票吗？”他问。 “当然可以，”那姑娘说。 我马上又回到售票处。 “我可以买那两张票吗？”我问。 “当然可以，不过这两张票是下星期三的，您是否还要呢？” “我还是买下的好，”我垂头丧气地说。 Lesson 20 One man in a boat 独坐孤舟 First listen and then answer the question. 听录音，然后回答以下问题。 Why is fishing the writer's favourite sport? Fishing is my favourite sport. I often fish for hours without catching anything. But this does not worry me. Some fishermen are unlucky. Instead of catching fish, they catch old boots and rubbish. I am even less lucky. I never catch anything -- not even old boots. After having spent whole mornings on the river, I always go home with an empty bag. 'You must give up fishing!' my friends say. 'It's a waste of time.' But they don't realize one important thing. I'm not really interested in fishing. I am only interested in sitting in a boat and doing nothing at all! New words and expressions 生词和短语 catch v. 抓到 fisherman n. 钓鱼人，渔民 boot n. 靴子 waste n. 浪费 realize v. 意识到 参考译文 钓鱼是我特别喜爱的一项运动。我经常一钓数小时却一无所获，但我从不为此烦恼。有些垂钓者就是不走运，他们往往鱼钓不到，却钓上来些旧靴子和垃圾。我的运气甚至还不及他们。我什么东西也未钓到过 -- 就连旧靴子也没有。我总是在河上呆上整整一上午，然后空着袋子回家。“你可别再钓鱼了！”我的朋友们说，“这是浪费时间。”然而他们没有认识到重要的一点，我并不是真的对钓鱼有兴趣，我感兴趣的只是独坐孤舟，无所事事！ Lesson 21 Mad or not? 是不是疯了 First listen and then answer the question. 听录音，然后回答以下问题。 Why do people think the writer is mad? Aeroplanes are slowly driving me mad. I live near an airport and passing planes can be heard night and day. The airport was built years ago, but for some reason it could not be used then. Last year, however, it came into use. Over a hundred people must have been driven away from their homes by the noise. I am one of the few people left. Sometimes I think this house will be knocked down by a passing plane. I have been offered a large sum of money to go away, but I am determined to stay here. Everybody says I must be mad and they are probably right. New words and expressions 生词和短语 mad adj. 发疯 reason n. 原因 sum n. 量 determined adj. 坚定的，下决心的 参考译文 飞机正在逐渐把我逼疯。我住在一个机场附近，过往飞机日夜不绝于耳。机场是许多年前建的，但由于某种原因当时未能启用。然而去年机场开始使用了。有100多人肯定是被噪音逼得已经弃家远去，我是少数留下来的人中的一个。有时我觉得这房子就要被一架飞过的飞机撞倒。他们曾向我提供一大笔钱让我搬走，但我决定留在这儿。大家都说我肯定是疯了，也许他们说的是对的。 Lesson 22 A glass envelope 玻璃信封 First listen and then answer the question. 听录音，然后回答以下问题。 How did Jane receive a letter from a stranger? My daughter, Jane, never dreamed of receiving a letter from a girl of her own age in Holland. Last year, we were travelling across the Channel and Jane put a piece of paper with her name and address on it into a bottle. She threw the bottle into the sea. She never thought of it again, but ten months later, she received a letter from a girl in Holland. Both girls write to each other regularly now. However, they have decided to use the post office. Letters will cost a little more, but they will certainly travel faster. New words and expressions 生词和短语 dream v. 做梦，梦想 age n. 年龄 channel n. 海峡 throw v. 扔，抛 参考译文 我的女儿简从未想过会接到荷兰一位同龄姑娘的来信。去年，当我们横渡英吉利海峡时，简把写有她姓名和住址的一张纸条装进了一只瓶子，又将瓶子扔进了大海。此后她就再没去想那只瓶子。但10个月以后，她收到了荷兰一位姑娘的来信。现在这两位姑娘定期通信了。然而她们还是决定利用邮局。这样会稍微多花点钱，但肯定是快得多了。 Lesson 23 A new house 新居 First listen and then answer the question. 听录音，然后回答以下问题。 Why is the new house special? I had a letter from my sister yesterday. She lives in Nigeria. In her letter, she said that she would come to England next year. If she comes, she will get a surprise. We are now living in a beautiful new house in the country. Work on it had begun before my sister left. The house was completed five months ago. In my letter, I told her that she could stay with us. The house has many large rooms and there is a lovely garden. It is a very modern house, so it looks strange to some people. It must be the only modern house in the district. New words and expressions 生词和短语 complete v. 完成 modern adj. 新式的，与以往不同的 strange adj. 奇怪的 district n. 地区 参考译文 昨天我收到了姐姐的一封信，她住在尼日利亚。在信中她说她明年将到英国来。如果她来了，她会感到非常惊奇了。我们现在住在乡间的一栋漂亮的新住宅里。这栋房子在我姐姐离开之前就已动工了，是在5个月以前竣工的。我在信中告诉她，她可以和我们住在一起。这栋房子里有许多房间，还有一个漂亮的花园。它是一栋非常现代化的住宅，因此在有些人看来很古怪。它肯定是这个地区唯一的一栋现代化住宅。 Lesson 24 If could be worse 不幸中之万幸 First listen and then answer the question. 听录音，然后回答以下问题。 Had the writer's money been stolen? I entered the hotel manager's office and sat down. I had just lost$50 and I felt very upset. 'I left the money in my room,' I said, 'and it's not there now.' The manager was sympathetic, but he could do nothing. 'Everyone's losing money these days,' he said. He started to complain about this wicked world but was interrupted by a knock at the door. A girl came in and put an envelope on his desk. It contained $50. 'I found this outside this gentleman's room,' she said. 'Well,' I said to the manager, 'there is still some honesty in this world!' New words and expressions 生词和短语 manager n. 经理 upset adj. 不安 sympathetic adj. 表示同情的 complain v. 抱怨 wicked adj. 很坏的，邪恶的 contain v. 包含，内装 honesty n. 诚实 参考译文 我走进饭店经理的办公室，坐了下来。我刚刚丢了50英镑，感到非常烦恼。“我把钱放在房间里，”我说，“可现在没有了。”经理深表同情，但却无能为力。“现在大家都在丢钱，”他说。他开始抱怨起这个邪恶的世道来，却被一阵敲门声打断了。一个姑娘走了进来，把一个信封放在了他桌上。它里面装着50英镑。“这是我在这位先生的房门外捡到的，”她说。“是啊，”我对那位经理说，“这世界上还是有诚实可言的！” Lesson 25 Do the English speak English? 英国人讲的是英语吗？ First listen and then answer the question. 听录音，然后回答以下问题。 Why does the writer not understand the porter? I arrived in London at last. The railway station was big, black and dark. I did not know the way to my hotel, so I asked a porter. I not only spoke English very carefully, but very clearly as well. The porter, however, could not understand me. I repeated my question several times and at last he understood. he answered me, but he spoke neither slowly nor clearly. 'I am a foreigner,' I said. Then he spoke slowly, but I could not understand him. My teacher never spoke English like that! The porter and I looked at each other and smiled. Then he said something and I understood it. 'You'll soon learn English!' he said. I wonder. In England, each person speaks a different language. The English understand each other, but I don't understand them! Do they speak English? New words and expressions 生词和短语 railway n. 铁路 porter n. 搬运工 several quantifier 几个 foreigner n. 外国人 wonder v. 感到奇怪 参考译文 我终于到了伦敦。火车站很大，又黑又暗。我不知道去饭店的路该怎么走，于是向一个搬运工打听。我的英语讲得不但非常认真，而且咬字也非常清楚。然而搬运工却不明白我的话。我把问话重复了很多遍。他终于听懂了。他回答了，但他讲得既不慢也不清楚。“我是个外国人，”我说。于是他说得慢了，可我还是听不懂。我的老师从来不那样讲英语！我和搬运工相视一笑。接着，他说了点什么，这回我听懂了。“您会很快学会英语的！”他说。我感到奇怪。在英国，人们各自说着一种不同的语言。英国人之间相互听得懂，可我却不懂他们的话！他们说的是英语吗？ Lesson 26 The best art critics 最佳艺术评论家 First listen and then answer the question. 听录音，然后回答以下问题。 Who is the student's best critic? I am an art student and I paint a lot of pictures. Many people pretend that they understand modern art. They always tell you what a picture is 'about'. Of course, many pictures are not 'about' anything. They are just pretty patterns. We like them in the same way that we like pretty curtain material. I think that young children often appreciate modern pictures better than anyone else. They notice more. My sister is only seven, but she always tells me whether my pictures are good or not. She came into my room yesterday. 'What are you doing?' she asked. 'I'm hanging this picture on the wall,' I answered. 'It's a new one. Do you like it?' She looked at it critically for a moment. 'It's all right,' she said, 'but isn't it upside down?' I looked at it again. She was right! It was! New words and expressions 生词和短语 art n. 艺术 critic n. 评论家 paint v. 画 pretend v. 假装 pattern n. 图案 curtain n. 窗帘，幕布 material n. 材料 appreciate v. 鉴赏 notice v. 注意到 whether conj. 是否 hang v. 悬挂，吊 critically adv. 批评地 upside down 上下颠倒地 参考译文 我是个学艺术的学生，画了很多画。有很多人装成很懂现代艺术的样子，总是告诉你一幅画的“意思”是什么。当然，有很多画是什么“意思”也没有的。它们就是些好看的图案，我们喜爱它们就像我们喜欢漂亮的窗帘布一样。我觉得小孩子们往往比任何人都更能欣赏现代绘画，他们观察到的东西更多。我的妹妹只有7岁，但她总能说出我的画是好还是坏。昨天她到我房里来了。 Lesson 27 A wet night 雨夜 First listen and then answer the question. 听录音，然后回答以下问题。 What happened to the boys in the night? Late in the afternoon, the boys put up their tent in the middle of a field. As soon as this was done, they cooked a meal over an open fire. They were all hungry and the food smelled good. After a wonderful meal, they told stories and sang songs by the campfire. But some time later it began to rain. The boys felt tired so they put out the fire and crept into their tent. Their sleeping bags were warm and comfortable, so they all slept soundly. In the middle of the night, two boys woke up and began shouting. The tent was full of water! They all leapt out of their sleeping bags and hurried outside. It was raining heavily and they found that a stream had formed in the field. The stream wound its way across the field and then flowed right under their tent! New words and expressions 生词和短语 tent n. 帐篷 field n. 田地，田野 smell v. 闻起来 wonderful adj. 极好的 campfire n. 营火，篝火 creep v. 爬行 sleeping bag 睡袋 comfortable adj. 舒适的，安逸的 soundly adv. 香甜地 leap v. 跳跃，跳起 heavily adv. 大量地 stream n. 小溪 form v. 形成 wind v. 蜿蜒 right adv. 正好 参考译文 傍晚时分，孩子们在田野中央搭起了帐篷。这件事刚刚做完，他们就在篝火上烧起了饭。他们全都饿了，饭菜散发出阵阵香味。他们美美地吃了一顿饭后，就围在营火旁讲起了故事，唱起了歌。但过了一阵子。天下起雨来，于是他们扑灭了篝火，钻进了帐篷。睡袋既暖和又舒服，所以，他们都睡得很香。午夜前后，有两个孩子醒了，大声叫了起来。原来帐篷里到处都是水！他们全都跳出睡袋，跑到外面。雨下得很大，他们发现地上已经形成了一条小溪。那小溪弯弯曲曲穿过田野，然后正好从他们的帐篷底下流过去。 Lesson 28 No parking 禁止停车 First listen and then answer the question. 听录音，然后回答以下问题。 What is Jasper White's problem? Jasper White is one of those rare people who believes in ancient myths. he has just bought a new house in the city, but ever since he moved in, he has had trouble with cars and their owners. When he returns home at night, he always finds that someone has parked a car outside his gate. Because of this, he has not been able to get his own car into his garage even once. Jasper has put up 'No Parking' signs outside his gate, but these have not had any effect. Now he has put an ugly stone head over the gate. It is one of the ugliest faces I have ever seen. I asked him what it was and he told me that it was Medusa, the Gorgon. jasper hopes that she will turn cars and their owners to stone. But none of them has been turned to stone yet! New words and expressions 生词和短语 rare adj. 罕见的 ancient adj. 古代的，古老的 myth n. 神话故事 trouble n. 麻烦 effect n. 结果，效果 Medusa n. 美杜莎（古希腊神话中3位蛇发女怪这一） Gorgon n. （古希腊神话中的）3位蛇发女怪这一（凡见其貌者都会变成石头） 参考译文 贾斯珀.怀特是少有的相信古代神话的人之一。他刚在城里买下一所新房子，但自从搬进去后，就和汽车及车主们发生了磨擦。当他夜里回到家时，总是发现有人把车停在他家大门外。为此，他甚至一次也没能把自己的车开进车库。贾斯珀曾把几块“禁止停车”的牌子挂在大门外边，但没有任何效果。现在他把一个丑陋的石雕头像放在了大门上边，这是我见过的最丑陋的头像之一。我问他那是什么？他告诉我那是蛇发女怪美杜莎。贾斯珀希望她把汽车和车主们都变成石头。但到目前为止还没有一个变成石头呢！ Lesson 29 Taxi! 出租汽车 First listen and then answer the question. 听录音，然后回答以下问题。 Does Captain Fawcett think any trip is too dangerous? Captain Ben Fawcett has bought an unusual taxi and has begun a new service. The 'taxi' is a small Swiss aeroplane called a 'Pilatus Porter'. This wonderful plane can carry seven passengers. The most surprising thing about it, however, is that it can land anywhere: on snow, water, or even on a ploughed field. Captain Fawcett's first passenger was a doctor who flew from Birmingham to a lonely village in the Welsh mountains. Since then, Captain Fawcett has flown passengers to many unusual places. Once he landed on the roof of a block of flats and on another occasion, he landed in a deserted car park. Captain Fawcett has just refused a strange request from a businessman. The man wanted to fly to Rockall, a lonely island in the Atlantic Ocean, but Captain Fawcett did not take him because the trip was too dangerous. New words and expressions 生词和短语 taxi n. Pilatus Porter land v. plough v. lonely adj. Welsh adj. roof n. block n. flat n. desert v. 参考译文 本.弗西特机长买了一辆不同寻常的出租汽车，并开始了一项新的业务。这辆“出租汽车”是一架小型瑞士飞机，叫“皮勒特斯.波特“号。这架奇妙的飞机可以载7名乘客。然而，最令人惊奇的是它能够在任何地方降落：雪地上，水面上，甚至刚耕过的田里。弗西特机长的第一名乘客是位医生，他从伯明翰飞往威尔士山区一个偏僻的村庄。从那时开始，弗西特机长已经载送乘客到过许多不寻常的地方。一次，他把飞机降落在了一栋公寓楼的屋顶上；还有一次，降落在了一个废弃的停车场上。弗西特机长刚刚拒绝了一位商人的奇怪要求。这个人想要飞往大西洋上的一个孤岛 -- 罗卡尔岛，弗西特机长之所以不送他去，是因为那段飞行太危险了。 Lesson 30 Football or polo? 足球还是水球？ First listen and then answer the question. 听录音，然后回答以下问题。 What happened to the man in the boat? The Wayle is a small river that cuts across the park near my home. I like sitting by the Wayle on fine afternoons. It was warm last Sunday, so I went and sat on the river bank as usual. Some children were playing games on the bank and there were some people rowing on the river. Suddenly, one of the children kicked a ball very hard and it went towards a passing boat. Some people on the bank called out to the man in the boat, but he did not hear them. The ball struck him so hard that he nearly fell into the water. I turned to look at the children, but there weren't any in sight: they had all run away! The man laughed when he realized what had happened. He called out to the children and threw the ball back to the bank. New words and expressions 生词和短语 polo n. 水球 Wayle n. 威尔（河名） cut v. 穿过 row v. 划（船） kick v. 踢 towards prep. 朝，向 nearly adv. 几乎 sight n. 眼界，视域 参考译文 威尔河是横穿过我家附近公园的一条小河。我喜欢在天气晴朗的下午到河边坐坐。上星期日天气很暖和。于是我和往常一样，又去河边坐着。河岸上有些孩子正在玩耍，河面上有些人正在划船。突然，一个孩子狠狠地踢了一脚球，球便向着一只划过来的小船飞去。岸上的一些人对着小船上的人高喊，但他没有听见。球重重地打在他身上，使他差点儿落入水中。我转过头去看那些孩子，但一个也不见，全都跑了！当那个人明白了发生的事情时，笑了起来。他大声叫着那些孩子，把球扔回到岸上。 Lesson 31 Success story 成功者的故事 First listen and then answer the question. 听录音，然后回答以下问题。 What was Frank's first job? Yesterday afternoon Frank Hawkins was telling me about his experiences as a young man. Before he retired, Frank was the head of a very large business company, but as a boy he used to work in a small shop. It was his job to repair bicycles and at that time he used to work fourteen hours a day. He saved money for years and in 1958 he bought a small workshop of his own. In his twenties Frank used to make spare parts for aeroplanes. At that time he had two helpers. In a few years the small workshop had become a large factory which employed seven hundred and twenty-eight people. Frank smiled when he remembered his hard early years and the long road to success. He was still smiling when the door opened and his wife came in. She wanted him to repair their grandson's bicycle! New words and expressions 生词和短语 retire v. 退休 company n. 公司 bicycle n. 自行车 save v. 积蓄 workshop n. 车间 helper n. 帮手，助手 employ v. 雇佣 grandson n. 孙子 参考译文 昨天下午弗兰克.霍金斯向我讲述了他年轻时的经历。在退休前，弗兰克是一家非常大的商业公司的经理，但他小时候却在一家小铺里做工。他那时的工作是修理自行车，并且通常是一天工作14个小时。他靠多年积蓄，于1958年买下了自己的一个小铺子。20多岁的时候，弗兰克曾生产飞机零配件。那时他有两个帮手。几年之后，小铺子已经发展成了一个雇有728人的大工厂。弗兰克回想着他早年的艰难经历和走过的漫长的成功之路，微笑了。他正笑着的时候门开了，他的妻子走了进来。她叫他去修理孙子的自行车。 Lesson 32 Shopping made easy 购物变得很方便 First listen and then answer the question. 听录音，然后回答以下问题。 Who was the thief? People are not so honest as they once were. The temptation to steal is greater than ever before -- especially in large shops. A detective recently watched a well-dressed woman who always went into a large store on Monday mornings. One Monday, there were fewer people in the shop than usual when the woman came in, so it was easier for the detective to watch her. The woman first bought a few small articles. After a little time, she chose one of the most expensive dresses in the shop and handed it to an assistant who wrapped it up for her as quickly as possible. Then the woman simply took the parcel and walked out of the shop without paying. When she was arrested, the detective found out that the shop assistant was her daughter. The girl 'gave' her mother a free dress once a week! New words and expressions 生词和短语 once adv. 曾经，以前 temptation n. 诱惑 article n. 物品，东西 wrap v. 包裹 simply adv. 仅仅 arrest v. 逮捕 参考译文 人们不再像以前那样诚实了。偷窃的诱惑力比以往任何时候都更强烈 -- 特别是在大的商店里。一名侦探最近注意上了一位穿着讲究的妇女，她总是在星期一上午进入一家大商场。有一个星期一，当这位妇女走进这家商场时，里面的人比往常少，因此，侦探比较容易监视她。这位妇女先是买了几样小商品。过了一会儿，她又选了商场里最昂贵的一件衣服，把它递给了售货员。那售货员以最快的速度为她包好了衣服。然后，那妇女拿过包就走出了商场，根本没有付钱。她被逮捕后。侦探发现原来那售货员是她的女儿。那姑娘每星期“送”她母亲一件免费的衣服！ Lesson 33 Out of the darkness 冲出黑暗 First listen and then answer the question. 听录音，然后回答以下问题。 Why was the girl in hospital? Nearly a week passed before the girl was able to explain what had happened to her. One afternoon she set out from the coast in a small boat and was caught in a storm. Towards evening, the boat struck a rock and the girl jumped into the sea. Then she swam to the shore after spending the whole night in the water. During that time she covered a distance of eight miles. Early next morning, she saw a light ahead. She knew she was near the shore because the light was high up on the cliffs. On arriving at the shore, the girl struggled up the cliff towards the light she had seen. That was all she remembered. When she woke up a day later, she found herself in hospital. New words and expressions 生词和短语 darkness n. explain v. coast n. storm n. towards prep. rock n. shore n. light n. ahead adv. cliff n. struggle v. hospital n. 参考译文 几乎过了一个星期，那姑娘才能讲述自己的遭遇。一天下午，她乘小船从海岸出发，遇上了风暴。天将黑时，小船撞在了一块礁石上，姑娘跳进了海里。她在海里游了整整一夜才游到岸边。在那段时间里，她游了8英里。第二天凌晨，她看到前方有灯光，知道自己已经接近岸边了，因为那灯光是在高高的峭壁上。到达岸边后，姑娘朝着她看到的灯光方向挣扎着往峭壁上爬去。她所记得的就是这些。第二天她醒来时，发现自己躺在医院里。 Lesson 34 Quick work 破案“神速” First listen and then answer the question. 听录音，然后回答以下问题。 How long had the police taken to find his bicycle? Dan Robinson has been worried all week. Last Tuesday he received a letter from the local police. In the letter he was asked to call at the station. Dan wondered why he was wanted by the police, but he went to the station yesterday and now he is not worried anymore. At the station, he was told by a smiling policeman that his bicycle had been found. Five days ago, the policeman told him, the bicycle was picked up in a small village four hundred miles away. It is now being sent to his home by train. Dan was most surprised when he heard the news. He was amused too, because he never expected the bicycle to be found. It was stolen twenty years ago when Dan was a boy of fifteen! New words and expressions 生词和短语 station n. （警察）局 most adv. 相当，非常 参考译文 丹.鲁宾逊焦虑了整整一个星期。上星期二他收到当地警察局的一封信，要他到警察局去一趟。丹奇怪警察为什么找他，但昨天还是去了，结果他一再担心了。在警察局里，一位面带笑容的警察告诉他，他的自行车找到了。那位警察对他说，那辆自行车是5天前在400英里外的一个小村里发现的，现在正用火车给他运回家来。丹听到这个消息后，惊奇万分，但又感到非常好笑，因为他从未指望那辆自行车还能找到。这是20年前丹还是一个15岁的孩子时被人偷走的！ Lesson 35 Stop thief! 捉贼！ First listen and then answer the question. 听录音，然后回答以下问题。 How did Roy stop the thieves? Roy Trenton used to drive a taxi. A short while ago, however, he became a bus driver and he has not regretted it. He is finding his new work far more exciting. When he was driving along Catford Street recently, he saw two thieves rush out of a shop and run towards a waiting car. One of them was carrying a bag full of money. Roy acted quickly and drove the bus straight at the thieves. The one with the money got such a fright that he dropped the bag. As the thieves were trying to get away in their car, Roy drove his bus into the back of it. While the battered car was moving away, Roy stopped his bus and telephoned the police. The thieves' car was badly damaged and easy to recognize. Shortly afterwards, the police stopped the car and both men were arrested. New words and expressions 生词和短语 while n. 一段时间 regret v. 后悔 far adv. 非常 rush v. 冲 act v. 行动 straight adv. 径直 fright n. 害怕 battered adj. 撞坏的 shortly adv. 很快，不久 afterwards adv. 以后 参考译文 罗伊.特雷顿原是开出租汽车的，然而就在前不久，他开上了公共汽车，也并不为此而感到后悔。他发觉自己的新工作令人兴奋得多。最近，当他正开车在凯特福德街上行驶时，看到有两个小偷从一家商店里冲出来，奔向等在那里的一辆汽车，其中一个提着一只装满钞票的提包。罗伊行动迅速，开车直冲窃贼而去。拿钱的那个小偷吓得把提包都扔了。当那两个小偷企图乘车逃跑时，罗伊驾驶他的公共汽车撞在了那辆车的后尾上。当那辆被撞坏的车开走后，罗伊停下车，给警察挂了电话。小偷的车损坏严重，很容易辨认。没过多久，警察就截住了那辆车，两个小偷都被抓住了。 Lesson 36 Across the Channel 横渡海峡 First listen and then answer the question. 听录音，然后回答以下问题。 What is Debbie going to try to do? Debbie Hart is going to swim across the English Channel tomorrow. She is going to set out from the French coast at five o'clock in the morning. Debbie is only eleven years old and she hopes to set up a new world record. She is a strong swimmer and many people feel that she is sure to succeed. Debbie's father will set out with her in a small boat. Mr. Hart has trained his daughter for years. Tomorrow he will be watching her anxiously as she swims the long distance to England. Debbie intends to take short rests every two hours. She will have something to drink but she will not eat any solid food. Most of Debbie's school friends will be waiting for her on the English coast. Among them will be Debbie's mother, who swam the Channel herself when she was a girl. New words and expressions 生词和短语 record n. 记录 strong adj. 强壮的 swimmer n. 游泳运动员 succeed v. 成功 train v. 训练 anxiously adv. 焦急地 intend v. 打算 solid adj. 固体的，硬的 参考译文 黛比.哈特准备明天横渡英吉利海峡。她打算早上5点钟从法国海岸出发。黛比只有11岁，她希望创一项新的世界纪录。她是一个游泳能手，很多人认为她一定能成功。黛比的父亲将乘一条小船同她一道出发。哈特先生训练她的女儿已经多年了，明天他将焦急地注视着女儿游过这段漫长的距离到达英国。黛比计划每两小时休息一下。她将喝些饮料，但不吃固体食物。黛比的大部分同学将在英国海岸等候她。他们当中还会有黛比的母亲，她本人还是个姑娘时，也曾横渡过英吉利海峡！ Lesson 37 The Olympic Games 奥林匹克运动会 First listen and then answer the question. 听录音，然后回答以下问题。 When was the last time this country hosted the Olympic Games? The Olympic Games will be held in our country in four years' time. As a great many people will be visiting the country, the government will be building new hotels, an immense stadium, and a new Olympic-standard swimming pool. They will also be building new roads and a special railway line. The Games will be held just outside the capital and the whole area will be called 'Olympic City'. Workers will have completed the new roads by the end of this year. By the end of next year, they will have finished work on the new stadium. The fantastic modern buildings have been designed by Kurt Gunter. Everybody will be watching anxiously as the new buildings go up. We are all very excited and are looking forward to the Olympic Games because they have never been held before in this country. New words and expressions 生词和短语 Olympic adj. 奥林匹克的 hold v. 召开 government n. 政府 immense adj. 巨大的 stadium n. 露天体育场 standard n. 标准 capital n. 首都 fantastic adj. 巨大的 design v. 设计 参考译文 4年以后，奥林匹克运动会将在我们国家举行。由于将有大批的人到我们国家来，所以政府准备建造一些新的饭店、一个大型体育场和一个新的奥运会标准游泳池。他们还将修筑一些新的道路和一条铁路专线。奥运会就在首都市郊举办，整个地区将被称作“奥林匹克城”。工人们将在今年年底前把新路铺好；到明年年底，他们将把新体育场建成。这些巨大的现代化建筑是由库尔特.冈特设计的。大家都将急切地注视着新建筑的建成。我们都非常激动，盼望着奥运会的到来，因为在这个国家里还从未举办过奥运会。 Lesson 38 Everything except the weather 唯独没有考虑到天气 First listen and then answer the question. 听录音，然后回答以下问题。 Why did Harrison sell his house so quickly? My old friend, Harrison, had lived in the Mediterranean for many years before he returned to England. He had often dreamed of retiring in England and had planned to settle down in the country. He had no sooner returned than he bought a house and went to live there. Almost immediately he began to complain about the weather, for even though it was still summer, it rained continually and it was often bitterly cold. After so many years of sunshine, Harrison got a shock. He acted as if he had never lived in England before. In the end, it was more than he could bear. He had hardly had time to settle down when he sold the house and left the country. The dream he had had for so many years ended there. Harrison had thought of everything except the weather. New words and expressions 生词和短语 except prep. 除了 Mediterranean n. 地中海 complain v. 抱怨 continually adv. 不断地 bitterly adv. 刺骨地 sunshine n. 阳光 参考译文 我的老朋友哈里森在回到英国以前曾多年居住在地中海地区。过去他常幻想退休后到英国，并计划在乡间安顿下来。他刚一回到英国便买下了一幢房子住了进去。但紧接着他就开始抱怨那里的天气了。因为即使那时仍为夏季，但雨总是下个不停，而且常常冷得厉害。在阳光下生活了那么多年的哈里森对此感到惊奇。他的举动就好像他从未在英国生活过一样。最后，他再也忍受不住，还没等安顿下来就卖掉了房子，离开了这个国家。他多年来的幻想从此破灭。哈里森把每件事情都考虑到了，唯独没想到天气。 Lesson 39 Am I all right? 我是否痊愈？ First listen and then answer the question. 听录音，然后回答以下问题。 Why did Mr. Gilbert telephone Dr. Millington? While John Gilbert was in hospital, he asked his doctor to tell him whether his operation had been successful, but the doctor refused to do so. The following day, the patient asked for a bedside telephone. When he was alone, he telephoned the hospital exchange and asked for Doctor Millington. When the doctor answered the phone, Mr. Gilbert said he was inquiring about a certain patient, a Mr. John Gilbert. He asked if Mr. Gilbert's operation had been successful and the doctor told him that it had been. He then asked when Mr. Gilbert would be allowed to go home and the doctor told him that he would have to stay in hosptial for another two weeks. Then Dr. Millington asked the caller if he was a relative of the patient. 'No,' the patient answered, 'I am Mr. John Gilbert.' New words and expressions 生词和短语 operation n. 手术 successful adj. 成功的 following adj. 下一个 patient n. 病人 alone adj. 独自的 exchange n. （电话的）交换台 inquire v. 询问，打听 certain adj. 某个 caller n. 打电话的人 relative n. 亲戚 参考译文 当约翰.吉尔伯特住院的时候，他问医生他的手术是否成功，但医生拒绝告诉他。第二天，这位病人要了一部床头电话。当房里只剩他一个人时，他挂通了医院的交换台，要求与米灵顿医生讲话。当这位医生接过电话时，吉尔伯特先生说他想询问一个病人的情况，是一位名叫约翰.吉尔伯特的先生。他问吉尔伯特先生的手术中否成功，医生告诉他手术很成功。然后他又问吉尔伯特先生什么时候可以回家，医生说他在医院还必须再住上两个星期。之后，米灵顿医生问打电话的人是否是病人的亲属。“不是，”病人回答说，“我就是约翰.吉尔伯特先生。” Lesson 40 Food and talk 进餐与交谈 First listen and then answer the question. 听录音，然后回答以下问题。 Was Mrs. Rumbold a good companion at dinner? Last week at a dinner party, the hostess asked me to sit next to Mrs. Rumbold. Mrs. Rumbold was a large, unsmiling lady in a tight black dress. She did not even look up when I took my seat beside her. Her eyes were fixed on her plate and in a short time, she was busy eating. I tried to make conversation. 'A new play is coming to "The Globe" soon,' I said. 'Will you be seeing it?' 'No,' she answered. 'Will you be spending your holidays abroad this year?' I asked. 'No,' she answered. 'Will you be staying in England?' I asked. 'No,' she answered. In despair, I asked her whether she was enjoying her dinner. 'Young man,' she answered, 'if you ate more and talked less, we would both enjoy our dinner!" New words and expressions 生词和短语 hostess n. 女主人 unsmiling adj. 不笑的，严肃的 tight adj. 紧身的 fix v. 凝视 globe n. 地球 despair n. 绝望 参考译文 在上星期的一次宴会上，女主人安排我坐在兰伯尔德夫人的身旁。兰伯尔德夫人是一位身材高大、表情严肃的女人，穿一件紧身的黑衣服。当我在她身旁坐下来的时候，她甚至连头都没有抬一下。她的眼睛盯着自己的盘子，不一会儿就忙着吃起来了。我试图找个话题和她聊聊。 “一出新剧要来‘环球剧场’上演了，”我说，“您去看吗？” “不，”她回答。 “您今年去国外度假吗？”我又问。 “不，”她回答。 “您就呆在英国吗？”我问。 “不，”她回答。 失望之中我问她饭是否吃得满意。 “年轻人，”她回答说，“如果你多吃点，少说点，我们两个都会吃得好的！” Lesson 41 Do you call that a hat? 你把那个叫帽子吗？ First listen and then answer the question. 听录音，然后回答以下问题。 What kind of shopping does the writer enjoy, do you think? 'Do you call that a hat?' I said to my wife. 'You needn't be so rude about it,' my wife answered as she looked at herself in the mirror. I sat down on one of those modern chairs with holes in it and waited. We had been in the hat shop for half an hour and my wife was still in front of the mirror. 'We mustn't buy things we don't need,' I remarked suddenly. I regretted saying it almost at once. 'You needn't have said that,' my wife answered. 'I needn't remind you of that terrible tie you bought yesterday.' 'I find it beautiful,' I said. 'A man can never have too many ties.' 'And a woman can't have too many hats,' she answered. Ten minutes later we walked out of the shop together. My wife was wearing a hat that looked like a lighthouse! New words and expressions 生词和短语 rude adj. 无礼的 mirror n. 镜子 hole n. 孔 remark v. 评说 remind v. 提醒 lighthouse n. 灯塔 参考译文 “你把那个叫帽子吗？”我对妻子说。 “你说话没必要这样不客气，”我的妻子边回答边照着镜子。 我坐在一个新式的满是网眼儿的椅子上，等待着。我们在这家帽店已经呆了半个小时了，而我的妻子仍在镜子面前。 “我们不应该买我们不需要的东西，”我突然发表意见说，但马上又后悔说了这话。 “你没必要这么说，”我妻子回答说，“我也不必提醒你昨天买的那条糟糕透了的领带。” “我觉得它好看，”我说，“男人有多少领带也不会嫌多。” “女人有多少帽子也不嫌多。”她回答。 10分钟以后，我们一道走出了商店。我妻子戴着一顶像灯塔一样的帽子。 Lesson 42 Not very musical 并非很懂音乐 First listen and then answer the question. 听录音，然后回答以下问题。 What happened when the snake charmer began to play jazz? As we had had a long walk through one of the markets of old Delhi, we stopped at a square to have a rest. After a time, we noticed a snake charmer with two large baskets at the other side of the square, so we went to have a look at him. As soon as he saw us, he picked up a long pipe which was covered with coins and opened one of the baskets. When he began to play a tune, we had our first glimpse of the snake. It rose out of the basket and began to follow the movements of the pipe. We were very much surprised when the snake charmer suddenly began to play jazz and modern pop songs. The snake, however, continued to 'dance' slowly. It obviously could not tell the difference between Indian music and jazz! New words and expressions 生词和短语 musical adj. 精通音乐的 market n. 市场，集市 snake charmer 玩蛇者（通常借音乐控制） pipe n. （吹奏的）管乐器 tune n. 曲调 glimpse n. 一瞥 snake n. 蛇 movement n. 动作 continue v. 继续 dance v. 跳舞 obviously adv. 显然 difference n. 差别 Indian adj. 印度的 参考译文 当我们穿过旧德里的市场时走了很长一段路，我们在一个广场上停下来休息。过了一会儿，我们注意到广场的那一边有一个带着两个大筐的耍蛇人，于是就走过去看看。他一见我们，就拿起了一个长长的上面镶有硬币的管乐器，并掀开了一个筐的盖子。当他开始吹奏一支曲子时，我们才第一次看到那条蛇。它从筐里探出身子，随着乐器的摆动而扭动。当耍蛇人突然又吹奏起爵士乐和现代流行乐曲时，我们感到非常惊奇。然而那蛇却还是缓慢地“舞动”着。显然，它分辨不出印度音乐和爵士乐！ Lesson 43 Over the South Pole 飞越南极 First listen and then answer the question. 听录音，然后回答以下问题。 How was the plane able to clear the mountains? In 1929, three years after his flight over the North Pole, the American explorer, R.E. Byrd, successfully flew over the South Pole for the first time. Though, at first, Byrd and his men were able to take a great many photographs of the mountains that lay below, they soon ran into serious trouble. At one point, it seemed certain that their plane would crash. It could only get over the mountains if it rose to 10,000 feet. Byrd at once ordered his men to throw out two heavy food sacks. The plane was then able to rise and it cleared the mountains by 400 feet. Byrd now knew that he would be able to reach the South Pole which was 300 miles away, for there were no more mountains in sight. The aircraft was able to fly over the endless white plains without difficulty. New words and expressions 生词和短语 pole n. （地球的）极 flight n. 飞行 explorer n. 探险家 lie v. 处于 serious adj. 严重的 point n. 地点 seem v. 似乎 crash v. 坠毁 sack n. 袋子 clear v. 越过 aircraft n. 飞机 endless adj. 无尽的 plain n. 平原 参考译文 美国探险家 R.E. 伯德在飞越北极3年之后，于1929年第一次飞越了南极。虽然开始时伯德和他的助手们拍下了飞机下面连绵群山的大量照片，但他们很快就陷入了困境。在有个地方，飞机似乎肯定要坠毁了。只有在飞至10,000英尺的高度时，它才能飞过这些山头。伯德马上命令他的助手们把两个沉重的食物袋扔掉，于是飞机可以上升了，它在离山头400英尺的高度飞越了过去。伯德这时知道他能够顺利飞抵300英里以外的南极了，因为前面再没有山了。飞机可以毫无困难地飞过这片茫茫无际的白色原野！ Lesson 44 Through the forest 穿过森林 First listen and then answer the question. 听录音，然后回答以下问题。 How did Mrs. Sterling get her bag back? Mrs. Anne Sterling did not think of the risk she was taking when she ran through a forest after two men. They had rushed up to her while she was having a picnic at the edge of a forest with her children and tried to steal her handbag. In the struggle, the strap broke and, with the bag in their possession, both men started running through the trees. Mrs. Sterling got so angry that she ran after them. She was soon out of breath, but she continued to run. When she caught up with them, she saw that they had sat down and were going through the contents of the bag, so she ran straight at them. The men got such a fright that they dropped the bag and ran away. 'The strap needs mending,' said Mrs. Sterling later, 'but they did not steal anything.' New words and expressions 生词和短语 forest n. 森林 risk n. 危险，冒险 picnic n. 野餐 edge n. 边缘 strap n. 带，皮带 possession n. 所有 breath n. 呼吸 contents n. （常用复数）内有的物品 mend v. 修理 参考译文 安.斯特林夫人在穿过森林追赶两个男人时，她并没有考虑到所冒的风险。刚才，当她和孩子们正在森林边上野餐的时候，这两个人冲到她跟前，企图抢走她的手提包。在争抢中，手提包的带断了，包落入这两个人手里，他们拔腿跑进了树林。斯特林夫人非常气愤，向着他们追了过去。只追了一会儿便上气不接下气了，但她还是继续追赶。当她赶上他们时，发现他们已经坐了下来，正翻着包里的东西。于是她直冲过去。这两个人吓了一跳，扔下提包逃跑了。“这提包带需要修理，”斯特林夫人事后说道，“不过他们什么也没偷走。” Lesson 45 A clear conscience 问心无愧 First listen and then answer the question. 听录音，然后回答以下问题。 How did Sam get his money back? The whole village soon learnt that a large sum of money had been lost. Sam Benton, the local butcher, had lost his wallet while taking his savings to the post office. Sam was sure that the wallet must have been found by one of the villagers, but it was not returned to him. Three months passed, and then one morning, Sam found his wallet outside his front door. It had been wrapped up in newspaper and it contained half the money he had lost, together with a note which said: 'A thief, yes, but only 50 per cent a thief!' Two months later, some more money was sent to Sam with another note: 'Only 25 per cent a thief now!' In time, all Sam's money was paid back in this way. The last note said: 'I am 100 per cent honest now!' New words and expressions 生词和短语 clear adj. 无罪的，不亏心的 conscience n. 良心，道德心 wallet n. 皮夹，钱夹 savings n. 存款 villager n. 村民 per cent 百分之...... 参考译文 整个村子很快知道，有一大笔钱丢失了。当地的屠户萨姆.本顿在把存款送往邮局的途中把钱包丢了。萨姆确信那钱包一定是被某个村民捡到了，可是却不见有人来送还给他。3个月过去了，后来在一天早晨，萨姆在自己的大门外发现了他的钱包。钱包是用报纸包着的，里面有他丢失的钱的一半，而且还附着一张纸条，上面写着：“一个小偷，是的，但只是一个50%的小偷！”又过了两个月，又有一些钱送还给了萨姆，又附了一张字条：“这回只是25%的小偷了！”很快，萨姆全部的钱都用同样的方式还了回来。最后的那张字条上写道：“我现在是一个100%的诚实人了！” Lesson 46 Expensive and uncomfortable 既昂贵又受罪 First listen and then answer the question. 听录音，然后回答以下问题。 What did the man in this story do? When a plane from London arrived at Sydney airport, workers began to unload a number of wooden boxes which contained clothing. No one could account for the fact that one of the boxes was extremely heavy. It suddenly occurred to one of the workers to open up the box. He was astonished at what he found. A man was lying in the box on top of a pile of woolen goods. He was so surprised at being discovered that he did not even try to run away. After he was arrested, the man admitted hiding in the box before the plane left London. He had had a long and uncomfortable trip, for he had been confined to the wooden box for over eighteen hours. The man was ordered to pay$3,500 for the cost of the trip. The normal price of a ticket is $2,000! New words and expressions 生词和短语 unload v. 卸（货） wooden adj. 木制的 extremely adv. 非常，极其 occur v. 发生 astonish v. 使惊讶 pile n. 堆 woollen n. 羊毛的 goods n. （常用复数）货物，商品 discover v. 发现 admit v. 承认 confine v. 关在（一个狭小的空间里） normal adj. 正常的，通常的 参考译文 当一架来自伦敦的飞机抵达悉尼机场时，工人们开始卸下装有服装的一批木箱。其中有只箱子特别重，可谁也弄不清是怎么回事。突然一个工人想到打开箱子看看。看到的情景使吃惊，箱内有一个人正躺在一堆毛织品之上。他由于被人发现而感到非常吃惊，甚至都没有企图逃跑。此人被逮捕后，承认他是在飞机离开伦敦前躲进箱里的。他经历了一次漫长而又难受的旅程，因为他在那木箱里闷了18个多小时。此人被责令交付旅费3,500英镑，而正常票价是2,000英镑！ Lesson 47 A thirsty ghost 嗜酒的鬼魂 First listen and then answer the question. 听录音，然后回答以下问题。 What evidence is there of a ghost? A public house which was recently bought by Mr.Ian Thompson is up for sale. Mr.Thompson is going to sell it because it is haunted. He told me that he could not go to sleep one night because he heard a strange noise coming from the bar. The next morning, he found that the doors had been blocked by chairs and the furniture had been moved. Though Mr.Thompson had turned the lights off before he went to bed, they were on in the morning. He also said that he had found five empty whisky bottles which the ghost must have drunk the night before. When I suggested that some villagers must have come in for a free drink, Mr.Thompson shook his head. The villagers have told him that they will not accept the pub even if he gives it away. New words and expressions 生词和短语 thirsty adj. 贪杯的 ghost n. 鬼魂 haunt v. （鬼）来访，闹鬼 block v. 堵 furniture n. 家具 whisky n. 威士忌酒 suggest v. 暗示 shake v. 摇动 accept v. 接受 参考译文 伊恩.汤普森先生最近才买的一个小酒店现在又要卖出去。汤普森先生之所以想卖它，是因为那里常闹鬼。他告诉我有天夜里他怎么也睡不着，因为他听到酒吧里传来一阵奇怪的响声。第二天早上，他发现酒吧间的门被椅子堵上了，家具也被挪动过。虽然汤普森临睡觉时把灯关了，但早晨灯却都亮着。他还说他发现了5只空的威士忌瓶子，肯定是鬼魂昨天晚上喝的。当我暗示说一定是村里有些人来喝不花钱的酒时，汤普森先生摇了摇头。村里的人已经告诉他，即使他把小酒店白送人，他们也不要。 Lesson 48 Did you want to tell me something? 你想对我说什么吗？ First listen and then answer the question. 听录音，然后回答以下问题。 Why did the writer become very worried? Dentists always ask questions when it is impossible for you to answer. My dentist had just pulled out one of my teeth and had told me to rest for a while. I tried to say something, but my mouth was full of cotton wool. He knew I collected match boxes and asked me whether my collection was growing. He then asked me how my brother was and whether I liked my new job in London. In answer to these questions I either nodded or made strange noises. Meanwhile, my tongue was busy searching out the hole where the tooth had been. I suddenly felt very worried, but could not say anything. When the dentist at last removed the cotton wool from my mouth, I was able to tell him that he had pulled out the wrong tooth. New words and expressions 生词和短语 pull v. 拔 cotton wool 药棉 collect v. 搜集 collection n. 收藏品，收集品 nod v. 点头 meanwhile adv. 同时 参考译文 牙科医生们总是在你无法作出回答的时候向你提出问题。我的牙科医生刚刚给我拔掉了一颗牙，叫我休息一会儿。我想说点什么，但我嘴里塞满了药棉。他知道我收集火柴盒，于是问我收藏的米柴盒是否在增加。接着他又问我的兄弟近来如何，问我是否喜欢伦敦的新工作。作为对这些问题的回答，我不是点头，就是发出奇怪的声音。与此同时，我的舌头正在忙着寻找刚拔掉的那颗牙的伤口。我突然非常着急起来，但却什么也说不出来。当那位牙医最后将药棉从我嘴中取出时，我总算有可能告诉他，他拔错了牙。 Lesson 49 The end of a dream 美梦告终 First listen and then answer the question. 听录音，然后回答以下问题。 How did the dream end? Tired of sleeping on the floor, a young man in Teheran saved up for years to buy a real bed. For the first time in his life, he became the proud owner of a bed which had springs and a mattress. Because the weather was very hot, he carried the bed on to the roof of his house. He slept very well for the first two nights, but on the third night, a storm blew up. A gust of wind swept the bed off the roof and sent it crashing into the courtyard below. The young man did not wake up until the bed had struck the ground. Although the bed was smashed to pieces, the man was miraculously unhurt. When he woke up, he was still on the mattress. Glancing at the bits of wood and metal that lay around him, the man sadly picked up the mattress and carried it into his house. After he had put it on the floor, he promptly went to sleep again. New words and expressions 生词和短语 tired adj. 厌烦的 real adj. 真正的 owner n. 主人 spring n. 弹簧 mattress n. 床垫 gust n. 一阵风 sweep v. 扫，刮 courtyard n. 院子 smash v. 碰碎，摔碎 miraculously adv. 奇迹般地 unhurt adj. 没有受伤的 glance v. 扫视 promptly adv. 迅速地 参考译文 德黑兰的一个人年轻人由于对睡地板感到厌倦，于是积蓄多年买了一张真正的床。他平生第一次自豪地拥有了一张既有弹簧又带床垫的床。由于天气很热，他便把床搬到了他的屋顶上。头两天晚上，他睡得非常好。但第三天晚上起了风暴。一阵大风把床从屋顶上刮了下来，把它摔碎在下面的院子里。那年轻人直到床撞到地上才醒了过来。尽管床摔成了碎片，但年轻人却奇迹地没有受伤。他醒来时，仍然躺在床垫上。年轻人看了一眼周围的碎木片和碎金属片，伤心地捡起了床垫，把它拿进了屋。他把床垫往地板上一放，很快又睡着了。 Lesson 50 Taken for a ride 乘车兜风 First listen and then answer the question. 听录音，然后回答以下问题。 Why did the writer not get off the bus at Woodford Green? I love travelling in the country, but I don't like losing my way. I went on an excursion recently, but my trip took me longer than I expected. 'I'm going to Woodford Green,' I said to the conductor as I got on the bus, 'but I don't know where it is.' 'I'll tell you where to get off.' answered the conductor. I sat in the front of the bus to get a good view of the countryside. After some time, the bus stopped. Looking round, I realized with a shock that I was the only passenger left on the bus. 'You'll have to get off here,' the conductor said. 'This is as far as we go.' 'Is this Woodford Green?' I asked. 'Oh dear,' said the conductor suddenly. 'I forgot to put you off.' 'It doesn't matter,' I said. 'I'll get off here.' 'We're going back now,' said the conductor. 'Well, in that case, I prefer to stay on the bus,' I answered. New words and expressions 生词和短语 ride n. 旅行 excursion n. 远足 conductor n. 售票员 view n. 景色 参考译文 我喜欢在乡间旅行，但却不愿意迷路。最近我作了一次短途旅行，但这次旅行所花费的时间比我预计的要长。 “我要去伍德福德草地，”我一上车就对售票员说，“但我不知道它在那儿。” “我来告诉您在哪儿下车，”售票员回答说。 我坐在汽车的前部，以便饱览农村风光。过了一些时候，车停了。我环视了一下身旁，惊奇地发现车里就只剩我一个乘客了。 “您得在这里下车，”售票员说，“我们的车就到此为止了。” “这里是伍德福德草地吗？”我问道。 “哎呀，”售票员突然说，“我忘了让您下车了。” “没关系，”我说，“我就在这儿下吧。” “我们现在要返回去，”售票员说。 “好吧，既然如此，我还是留在车上吧。”我回答说。 Lesson 51 Reward for virtue 对美德的奖赏 First listen and then answer the question. 听录音，然后回答以下问题。 Why did Hugh's diet not work? My friend, Hugh, has always been fat, but things got so bad recently that he decided to go on a diet. He began his diet a week ago. First of all, he wrote out a long list of all the foods which were forbidden. The list included most of the things Hugh loves: butter, potatoes, rice, beer, milk, chocolate; and sweets. Yesterday I paid him a visit. I rang the bell and was not surprised to see that Hugh was still as fat as ever. He led me into his room and hurriedly hid a large parcel under his desk. It was obvious that he was very embarrassed. When I asked him what he was doing, he smiled guiltily and then put the parcel on the desk. He explained that his diet was so strict that he had to reward himself occasionally. Then he showed me the contents of the parcel. It contained five large bars of chocolate and three bags of sweets! New words and expressions 生词和短语 reward n. 报偿 virtue n. 美德 diet n. 节食 forbid v. 禁止 hurriedly adv. 匆忙地 embarrass v. 使尴尬 guiltily adv. 内疚地 strict adj. 严格的 reward v. 给奖赏 occasionally adv. 偶尔地 参考译文 我的朋友休一直很胖，但是近来情况变得越发糟糕，以致他决定节食。他是一星期前开始节食的。首先，他开列了一张长长的单子，上面列了所有禁吃的食物。这张单子上的大多数食物都是休喜欢吃的：黄油、土豆、米饭、啤酒、牛奶、巧克力和糖果。昨天我去看望了他。我按响了门铃，当看到休仍和往常一样胖时，我并不感到惊奇。他把我领进屋，慌忙把一个大包藏到了桌子下面。显然他感到很尴尬。当我问他正干什么时，他内疚地笑了，然后把那个大包拿到了桌上。他解释说，他的饮食控制得太严格了，以致不得不偶尔奖赏自己一下。接着他给我看了包里的东西。里面装了5大块巧克力和3袋糖果！ Lesson 52 A pretty carpet 漂亮的地毯 First listen and then answer the question. 听录音，然后回答以下问题。 What is the writer's carpet made of? We have just moved into a new house and I have been working hard all morning. I have been trying to get my new room in order. This has not been easy because I own over a thousand books. To make matters worse, the room is rather small, so I have temporarily put my books on the floor. At the moment, they cover every inch of floor space and I actually have to walk on them to get in or out of the room. A short while ago, my sister helped me to carry one of my old bookcases up the stairs. She went into my room and got a big surprise when she saw all those books on the floor. 'This is the prettiest carpet I have ever seen,' she said. She gazed at it for some time then added, 'You don't need bookcases at all. You can sit here in your spare time and read the carpet!' New words and expressions 生词和短语 temporarily adv. 暂时地 inch n. 英寸（度量单位） space n. 空间 actually adv. 实际上 参考译文 我们刚刚搬进一所新房子，我辛辛苦苦地干了整整一个上午。我试图把我的新房间收拾整齐，但这并不容易，因为我有1,000多本书。更糟糕的是房间还非常小，所以我暂时把书放在了地板上。这会儿，书把地板的每一点空隙都占据了，我实际上是踩着这些书进出房间的。几分钟前，我妹妹帮我把一个旧书橱抬上了楼。她走进我的房间，当她看到地板上的那些书时，大吃一惊。“这是我见过的最漂亮的地毯，”她说。她盯着“地毯”看了一会儿，又说：“你根本用不着书橱，空闲时你可以坐在这儿读地毯！” Lesson 53 Hot snake 触电的蛇 First listen and then answer the question. 听录音，然后回答以下问题。 What caused the fire? At last firemen have put out a big forest fire in California. Since then, they have been trying to find out how the fire began. Forest fires are often caused by broken glass or by cigarette ends which people carelessly throw away. Yesterday the firemen examined the ground carefully, but were not able to find any broken glass. They were also quite sure that a cigarette end did not start the fire. This morning, however, a firemen accidentally discovered the cause. He noticed the remains of a snake which was wound round the electric wires of a 16,000-volt power line. In this way, he was able to solve the mystery. The explanation was simple but very unusual. A bird had snatched up the snake from the ground and then dropped it on to the wires. The snake then wound itself round the wires. When it did so, it sent sparks down to the ground and these immediately started a fire. New words and expressions 生词和短语 hot adj. 带电的，充电的 fireman n. 消防队员 cause v. 引起； n. 原因 examine v. 检查 accidentally adv. 意外地，偶然地 remains n. 尸体，残骸 wire n. 电线 volt n. 伏特（电压单位） power line 电力线 solve v. 解决 mystery n. 谜 snatch v. 抓住 spark n. 电火花 参考译文 消防队员们终于扑灭了加利福尼亚的一场森林大火。从那时起，他们一直试图找出起火的原因。森林火灾时常由破碎的玻璃或人们随手扔掉的香烟头引起。昨天，消防队员仔细查看了地面，但未能发现碎玻璃。他们还十分肯定火灾也不是由烟头引起的。然而今天上午，一个消防队员偶然发现了起火的原因。他发现了缠绕在16,000伏高压线上的一条死蛇。就这样，他解开了起火之谜。解释很简单，却异乎寻常。一只鸟把蛇从地上抓起来，然后把它扔到了电线上。于是蛇就缠住了几根电线。当它这样做时，把火花送到了地面，这些火花立刻引起了一场大火。 Lesson 54 Sticky fingers 粘糊的手指 First listen and then answer the question. 听录音，然后回答以下问题。 What two interruptions did the writer have? After breakfast, I sent the children to school and then I went to the shops. It was still early when I returned home. The children were at school, my husband was at work and the house was quiet. So I decided to make some meat pies. In a short time I was busy mixing butter and flour and my hands were soon covered with sticky pastry. At exactly that moment, the telephone rang. Nothing could have been more annoying. I picked up the receiver between two sticky fingers and was dismayed when I recognized the voice of Helen Bates. It took me ten minutes to persuade her to ring back later. At last I hung up the receiver. What a mess! There was pastry on my fingers, on the telephone, and on the doorknobs. I had no sooner got back to the kitchen than the doorbell rang loud enough to wake the dead. This time it was the postman and he wanted me to sign for a registered letter! New words and expressions 生词和短语 sticky adj. 粘的 finger n. 手指 pie n. 馅饼 mix v. 混合，拌和 pastry n. 面糊 annoying adj. 恼人的 receiver n. 电话的话筒 dismay v. 失望，泄气 recognize v. 认出，听出 persuade v. 说服，劝说 mess n. 乱七八糟 doorknob n. 门把手 sign v. 签字 register v. 挂号邮寄 参考译文 早饭后，我送孩子们上学，然后就去了商店。我回到家时，时间还早。孩子们在上学，我丈夫在上班，家里清静得很。于是我决定做些肉馅饼。不一会儿我就忙着调拌起了黄油和面粉，很快我的手上就沾满了粘粘的面糊。恰恰在此时，电话铃响了。没有什么能比这更烦人了。我用两个沾满面糊的手指捏起了话筒。当听出是海伦.贝茨的声音时，非常丧气。我用了10分钟的时间才说服她过会儿再来电话。我终于挂上了话筒。真是糟糕透了！我的手指上、电话机上以及门的把手上，都沾上了面糊。我刚回到厨房，门铃又响了起来，响声足以把死人唤醒。这次是邮递员，他要我签收一封挂号信！ Lesson 55 Not a gold mine 并非金矿 First listen and then answer the question. 听录音，然后回答以下问题。 What did the team find? Dreams of finding lost treasure almost came true recently. A new machine called 'The Revealer' has been invented and it has been used to detect gold which has been buried in the ground. The machine was used in a cave near the seashore where -- it is said -- pirates used to hide gold. The pirates would often bury gold in the cave and then fail to collect it. Armed with the new machine, a search party went into the cave hoping to find buried treasure. The leader of the party was examining the soil near the entrance to the cave when the machine showed that there was gold under the ground. Very excited, the party dug a hole two feel deep. They finally found a small gold coin which was almost worthless. The party then searched the whole cave thoroughly but did not find anything except an empty tin trunk. In spite of this, many people are confident that 'The Revealer' may reveal something of value fairly soon. New words and expressions 生词和短语 gold n. 金子 mine n. 矿 treasure n. 财宝 revealer n. 探测器 invent v. 发明 detect v. 探测 bury v. 埋藏 cave n. 山洞 seashore n. 海岸 pirate n. 海盗 arm v. 武装 soil n. 泥土 entrance n. 入口 finally adv. 最后 worthless adj. 毫无价值的 thoroughly adv. 彻底地 trunk n. 行李箱 confident adj. 有信心的 value n. 价值 参考译文 最近，找到失踪宝藏的梦想差一点儿变成现实。一种叫“探宝器”的新机器已经发明出来，并被人们用来探测地下埋藏的金子。在靠近海边的一个据说过去海盗常在里面藏金子的岩洞里，这种机器被派上了用场。海盗们过去常把金子埋藏在那个洞里，可后来却没能取走。一支用这种新机器装备起来的探宝队进入了这个岩洞，希望找到埋藏着的金子。当这个队的队长正在检查洞口附近的土壤时，那台机器显示出它的下面埋有金子。队员们异常激动，就地挖了一个两英尺深的坑，但最后找到的是一枚几乎一钱不值的小金币。队员们接着又把整个洞彻底搜寻了一遍，但除了一只空铁皮箱外什么也没找到。尽管如此，很多人仍然相信“探宝器”很快就会探出值钱的东西来。 Lesson 56 Faster than sound! 比声音还快！ First listen and then answer the question. 听录音，然后回答以下问题。 How fast did the winning car go? Once a year, a race is held for old cars. A lot of cars entered for this race last year and there was a great deal of excitement just before it began. One of the most handsome cars was a Rolls-Royce Silver Ghost. The most unusual car was a Benz which had only three wheels. Built in 1885, it was the oldest car taking part. After a great many loud explosions, the race began. Many of the cars broke down on the course and some drivers spent more time under their cars than in them! A few cars, however, completed the race. The winning car reached a speed of forty miles an hour -- much faster than any of its rivals. It sped downhill at the end of the race and its driver had a lot of trouble trying to stop it. The race gave everyone a great deal of pleasure. It was very different from modern car races but no less exciting. New words and expressions 生词和短语 sound n. 声音 excitement n. 激动，兴奋 handsome adj. 漂亮的；美观的 Rolls-Royce 罗尔斯--罗伊斯 Benz n. 奔驰 wheel n. 轮子 explosion n. 爆炸，轰响 course n. 跑道；行程 rival n. 对手 speed v. 疾驶 downhill adv. 下坡 参考译文 旧式汽车的比赛每年举行一次。去年有很多汽车参加了这项比赛。比赛开始之前，人们异常激动。最漂亮的汽车之一是罗尔斯--罗伊斯生产的银鬼汽车，而最不寻常的一辆则要属只有3只轮子的奔驰牌汽车了。该车造于1885年，是参赛车中最老的一辆。在好一阵喧闹的爆炸声之后，比赛开始了。很多汽车在途中就抛了锚，而有些驾驶员花在汽车底下的时间比坐在汽车里面的时间还长。然而还是有几辆汽车跑完了全程。获胜的那辆车达到了时速40英里--远远超过任何对手。它在接近终点时，冲下了山坡，驾驶员费了好大劲才把车停下来。这次比赛使每个人都挺开心。它虽然与现代汽车比赛大不相同，但激动人心的程度并不亚于现代化汽车大赛。 Lesson 57 Can I help you, madam? 您要买什么，夫人？ First listen and then answer the question. 听录音，然后回答以下问题。 Did the woman get what she wanted? A woman in jeans stood at the window of an expensive shop. Though she hesitated for a moment, she finally went in and asked to see a dress that was in the window. The assistant who served her did not like the way she was dressed. Glancing at her scornfully, he told her that the dress was sold. The woman walked out of the shop angrily and decided to punish the assistant next day. She returned to the shop the following morning dressed in a fur coat, with a handbag in one hand and a long umbrella in the other. After seeking out the rude assistant, she asked for the same dress. Not realizing who she was, the assistant was eager to serve her this time. With great difficulty, he climbed into the shop window to get the dress. As soon as she saw it, the woman said she did not like it. She enjoyed herself making the assistant bring almost everything in the window before finally buying the dress she had first asked for. New words and expressions 生词和短语 madam n. （对妇女的尊称）太太，夫人 jeans n. 牛仔裤 hesitate v. 犹豫，迟缓 serve v. 接待（顾客） scornfully adv. 轻蔑地 punish v. 惩罚 fur n. 裘皮 eager adj. 热切的，热情的 参考译文 一位穿着牛仔裤的妇女站在一家高档商店的橱窗前。她虽然犹豫了片刻，但终于还是走进了商店，要求把陈列在橱窗里的一件衣服拿给她看。接待她的售货员不喜欢她的那副打扮，轻蔑地看了她一眼后，便告诉她那件衣服已经卖出去了。这位妇女怒气冲冲地走出了商店，决定第二天教训一下那个售货员。第二天上午，她又来到这家商店，穿了一件裘皮大衣，一只手拎着一只手提包，另一只手拿着一把长柄伞。找到那个无礼的售货员后，她还要看昨天的那件衣服。那个售货员没有认出她是谁，这一回接待她的态度非常殷勤。费了好大劲儿，他爬进橱窗去取那件衣服。这位妇女对那件衣服只看一眼，就说不喜欢。她开心地迫使那位售货员把橱窗里几乎所有的东西都拿了出来，最后才买下了她最先要看的那一件。 Lesson 58 A blessing in disguise? 是因祸得福吗？ First listen and then answer the question. 听录音，然后回答以下问题。 Why does the vicar refuse to cut down the tree? The tiny village of Frinley is said to possess a 'cursed tree'. Because the tree was mentioned in a newspaper, the number of visitors to Frinley has now increased. The tree was planted near the church fifty years ago, but it is only in recent years that it has gained an evil reputation. It is said that if anyone touches the tree, he will have bad luck; if he picks a leaf, he will die. Many villagers believe that the tree has already claimed a number of victims. The vicar has been asked to have the tree cut down, but so far he has refused. He has pointed out that the tree cut down, but so far he has refused. He has pointed out that the tree is a useful source of income, as tourists have been coming from all parts of the country to see it. In spite of all that has been said, the tourists have been picking leaves and cutting their names on the tree-trunk. So far, not one of them has been struck down by sudden death! New words and expressions 生词和短语 blessing n. 福分，福气 disguise n. 伪装 tiny adj. 极小的 possess v. 拥有 cursed adj. 可恨的 increase v. 增加 plant v. 种植 church n. 教堂 evil adj. 坏的 reputation n. 名声 claim v. 以......为其后果 victim n. 受害者，牺牲品 vicar n. 教区牧师 source n. 来源 income n. 收入 trunk n. 树干 参考译文 据说弗林利这个小村里有一棵“该诅咒的树”。就因为报上提到过这棵树，所以现在来弗林利参观的人越来越多。该树是50年前栽在教堂附近的，但只是近几年才得到了一个坏名声。据说，谁要是触摸了这棵树，谁就会交上恶运；如果谁摘了一片树叶，谁就会死去。很多村民相信此树已经害了不少人。人们曾请求教区的牧师叫人把树砍掉，但他直到现在也没有同意。他指出，由于人们从全国各地纷纷前来参观这棵树，它成了一个有用的财源。尽管有上述种种说法，但游客们还是照常摘树叶和把他们的名字刻在树干上。然而到目前为止，还没有一个人暴死呢！ Lesson 59 In or out? 进来还是出去？ First listen and then answer the question. 听录音，然后回答以下问题。 Why did Rex run away? Our dog, Rex, used to sit outside our front gate and dark. Every time he wanted to come into the garden he would bark until someone opened the gate. As the neighbours complained of the noise, my husband spent weeks training him to press his paw on the latch to let himself in. Rex soon became an expert at opening the gate. However, when I was going out shopping last week, I noticed him in the garden near the gate. This time he was barking so that someone would let him out! Since then, he has developed another bad habit. As soon as he opens the gate from the outside, he comes into the garden and waits until the gate shuts. Then he sits and barks until someone lets him out. After this he immediately lets himself in and begins barking again. Yesterday my husband removed the gate and Rex got so annoyed we have not seen him since. New words and expressions 生词和短语 bark v. 狗叫 press v. 按，压 paw n. 脚爪 latch n. 门闩 expert n. 专家 develop v. 养成 habit n. 习惯 remove v. 拆掉，取下 参考译文 我家的狗雷克斯，过去常坐在大门外面叫。每当它想到花园里来时，便汪汪叫个不停，直到有人把门打开。由于邻居们对狗叫很有意见，所以我丈夫花了几个星期的时间训练它用脚爪按住门闩把自己放进来。雷克斯很快成了开门的专家。然而上星期我正要出去买东西时，发现它正呆在花园里边靠门的地方。这次它叫着让人把它放出去！从那以后，它养成了另外一种坏习惯。它从外面把门一打开，就走进花园，等着门自动关上。这之后他就坐下汪汪叫起来，直到有人来把它放出去。出去之后，它又马上把自己放进来，接着再开始叫。昨天，我丈夫把门卸了下来，雷克斯很生气，此后我们便再也没有见到它。 Lesson 60 The future 卜算未来 First listen and then answer the question. 听录音，然后回答以下问题。 Does what Madam Bellinsky said come true? At a village fair, I decided to visit a fortune-teller called Madam Bellinsky. I went into her tent and she told me to sit down. After I had given her some money, she looked into a crystal ball and said: 'A relation of yours is coming to see you. She will be arriving this evening and intends to stay for a few days. The moment you leave this tent, you will get a big surprise. A woman you know well will rush towards you. She will speak to you and then she will lead you away from this place. That is all.' As soon as I went outside, I forgot all about Madam Bellinsky because my wife hurried towards me. 'Where have you been hiding?' she asked impatiently. 'Your sister will be here in less than an hour and we must be at the station to meet her. We are late already.' As she walked away, I followed her out of the fair. New words and expressions 生词和短语 future n. 未来，前途 fair n. 集市 fortune-teller n. 算命人 crystal n. 水晶 relation n. 亲属 impatiently adv. 不耐烦地 参考译文 在一个乡村集市上，我决定去拜访一位称作别林斯夫人的算命人。我走进她的帐篷，她叫我坐下。我给了她一些钱后，她便查看着一个水晶球说道：“您的一个亲戚就要来看您了。她将于今天傍晚到达，并准备住上几天。您一走出这个帐篷，就会大吃一惊。一位您很熟悉的女人将向您冲来。她会对您说点什么，然后带您离开这个地方。就是这些。” 我一走出帐篷，就把别林斯基夫人给算卦的事忘得一干二净了，因为我的妻子正匆匆向我跑来。“你躲到哪儿去了？”她不耐烦地问，“再有不到一个小时你姐姐就要到这儿了，我们得去车站接她。现在就已经晚了。”当她走开时，我也跟着她出了集市。 Lesson 61 Trouble with the Hubble 哈勃望远镜的困境 First listen and then answer the question. 听录音，然后回答以下问题。 What is the special importance of a telescope in space? The Hubble telescope was launched into space by NASA on April 20,1990 at a cost of over a billion dollars. Right from the start there was trouble with the Hubble. The pictures it sent us were very disappointing because its main mirror was faulty! NASA is now going to put the telescope right, so it will soon be sending up four astronauts to repair it. The shuttle Endeavour will be taking the astronauts to the Hubble. A robot-arm from the Endeavour will grab the telescope and hold it while the astronauts make the necessary repairs. Of course, the Hubble is above the earth's atmosphere, so it will soon be sending us the clearest pictures of the stars and distant galaxies that we have ever seen. The Hubble will tell us a great deal about the age and size of the universe. By the time you read this, the Hubble's eagle eye will have sent us thousands and thousands of wonderful pictures. New words and expressions 生词和短语 Hubble n. 哈勃 telescope n. 望远镜 launch v. 发射 space n. 空间 NASA n.(National Aeronautics and Space Administration) 国家航空和航天局 billion n. 10亿 faulty adj. 有错误的 astronaut n. 宇航员 shuttle n. 航天飞机 Endeavour n. “奋进”号 robot-arm n. 机器手 grab v. 抓 atmosphere n. 大气层 distant adj. 遥远的 galaxy n. 星系 universe n. 宇宙 eagle eye 鹰眼 参考译文 哈勃望远镜于1990年4月20日由国家航空航天局发射升空，耗资10多亿美元。从最开始哈勃望远镜就有问题。它传送给我们的图像很令人失望，因为它的主要镜子有误差。国家航天局准备纠正这一错误，为此将把4名宇航员送入太空修复望远镜。“奋进”号航天飞机将把宇航员送上哈勃。当宇航员进行必要的修复工作时，“奋进”号上的一只机器手将抓住望远镜并托住它。当然，哈勃位于地球的大气层之外，因此，它很快就会给我们传送我们所见到过的、有关行星和远距离星系的最清晰的照片。哈勃将告诉我们有关宇宙的年龄和大小的许多事情。等到你读到这篇文章时，敏锐的哈勃望远镜已经为我们送来了成千上万张精彩的照片。 Lesson 62 After the fire 大火之后 First listen and then answer the question. 听录音，然后回答以下问题。 What was the danger to the villages after the fire? Firemen had been fighting the forest for nearly three weeks before they could get it under control. A short time before, great trees had covered the countryside for miles around. Now, smoke still rose up from the warm ground over the desolate hills. Winter was coming on and the hills threatened the surrounding villages with destruction, for heavy rain would not only wash away the soil but would cause serious floods as well. When the fire had at last been put out, the forest authorities ordered several tons of a special type of grass-seed which would grow quickly. The seed was sprayed over the ground in huge quantities by aeroplanes. The planes had been planting seed for nearly a month when it began to rain. By then, however, in many places the grass had already taken root. In place of the great trees which had been growing there for centuries patches of green had begun to appear in the blackened soil. New words and expressions 生词和短语 control n. 控制 smoke n. 烟 desolate adj. 荒凉的 threaten v. 威胁 surrounding adj. 周围的 destruction n. 破坏，毁灭 flood n. 洪水，水灾 authority n. （常用复数）当局 grass-seed n. 草籽 spray v. 喷撒 quantity n. 量 root n. 根 century n. 世纪 patch n. 小片 blacken v. 变黑，发暗 参考译文 消防队员们同那场森林大火搏斗了将近3个星期才最后把火势控制住。就在不久之前，参天大树还覆盖着方圆数英里的土地。而现在，发热的地面上仍然升腾着烟雾，弥漫在荒凉的山丘上。冬季即将来临，这些山丘对周围的村庄具有毁灭性的威胁，因为大雨不仅会冲走土壤，而且还会引起严重的水灾。在大火最后被扑灭后，森林管理当局订购了好几吨一种生长迅速的特殊类型的草籽。飞机把这种草籽大量地撒播在地上。飞机撒播近一个月后，开始下起雨来。然而到那时，很多地方的草已经生了根。一片片的绿草开始出现在这片烧焦的土地上，代替了多少世纪以来一直生长在那里的参天大树。 Lesson 63 She was not amused 她并不觉得好笑 First listen and then answer the question. 听录音，然后回答以下问题。 Why did Jenny want to leave the wedding reception? Jeremy Hampden has a large circle of friends and if very popular at parties. Everybody admires him for his great sense of humour -- everybody, that is, except his six-year-old daughter, Jenny. Recently, one of Jeremy's closest friends asked him to make a speech at a wedding reception. This is the sort of thing that Jeremy loves. He prepared the speech carefully and went to the wedding with Jenny. he had included a large number of funny stories in the speech and, of course, it was a great success. As soon as he had finished, Jenny told him she wanted to go home. Jeremy was a little disappointed by this but he did as his daughter asked. On the way home, he asked Jenny if she had enjoyed the speech. To his surprise, she said she hadn't. Jeremy asked her why this was so and she told him that she did not like to see so many people laughing at him! New words and expressions 生词和短语 circle n. 圈子 admire v. 赞美，钦佩 close adj. 亲密的 wedding n. 婚礼 reception n. 招待会 sort n. 种类 参考译文 杰里米.汉普登交际甚广，是各种聚会上深受大家欢迎的人。人人都钦佩他那绝妙的幽默感 -- 人人，就是说，除他6岁的女儿珍妮之外的每一个人。最近，杰里米的一个最亲密的朋友请他在一个婚礼上祝词。这正是杰里米喜欢做的事情。他认真准备了讲稿，带着珍妮一道去参加了婚礼。他的祝词里面加进了大量逗人的故事，自然大获成功。他刚一讲完，珍妮就对他说她要回家。这不免使杰里米有点扫兴，但他还是按照女儿的要求做了。在回家的路上，他问珍妮是否喜欢他的祝词。使他吃惊的是，她说她不喜欢。杰里米问他为何不喜欢，她说她不愿意看到那么多的人嘲笑他！ Lesson 64 The Channel Tunnel 海峡隧道 First listen and then answer the question. 听录音，然后回答以下问题。 Why was the first tunnel not completed? In 1858, a French engineer, Aime Thome de Gamond, arrived in England with a plan for a twenty-one-mile tunnel under the English Channel. He said that it would be possible to build a platform in the centre of the Channel. This platform would serve as a port and a railway station. The tunnel would be well-ventilated if tall chimneys were built above sea level. In 1860, a better plan was put forward by an Englishman, William Low. He suggested that a double railway-tunnel should be built. This would solve the problem of ventilation, for if a train entered this tunnel, it would draw in fresh air behind it. Forty-two years later a tunnel was actually begun. If, at the time, the British had not feared invasion, it would have been completed. The world had to wait almost another 100 years for the Channel Tunnel. It was officially opened on March 7,1994, finally connecting Britain to the European continent. New words and expressions 生词和短语 tunnel n. 隧道 port n. 港口 ventilate v. 通风 chimney n. 烟囱 sea level 海平面 double adj. 双的 ventilation n. 通风 fear v. 害怕 invasion n. 入侵，侵略 officially adv. 正式地 connect v. 连接 European adj. 欧洲的 continent n. 大陆 参考译文 1858年，一位名叫埃梅.托梅.德.干蒙的法国工程师带着建造一条长21英里、穿越英吉利海陕的隧道计划到了英国。他说，可以在隧道中央建造一座平台，这座平台将用作码头和火车站。如果再建些伸出海面的高大的烟囱状通风管，隧道就具备了良好的通风条件。1860年，一位名叫威廉.洛的英国人提出了一项更好的计划。他提议建一条双轨隧道，这样就解决了通风问题。因为如果有列火车开进隧道，它就把新鲜空气随之抽进了隧道。42年以后，隧道实际已经开始建了。如果不是因为那时英国人害怕入侵，隧道早已建成了。世界不得不再等将近100年才看到海峡隧道竣工。它于1994年3月7日正式开通，将英国与欧洲大陆连到了一起。 Lesson 65 Jumbo versus the police 小象对警察 First listen and then answer the question. 听录音，然后回答以下问题。 Why did the police have to push Jumbo off the main street? Last Christmas, the circus owner, Jimmy Gates, decided to take some presents to a children's hospital. Dressed up as Father Christmas and accompanied by a 'guard of honour' of six pretty girls, he set off down the main street of the city riding a baby elephant called Jumbo. He should have known that the police would never allow this sort of thing. A policeman approached Jimmy and told him he ought to have gone along a side street as Jumbo was holding up the traffic. Though Jimmy agreed to go at once, Jumbo refused to move. Fifteen policemen had to push very hard to get him off the main street. The police had a difficult time, but they were most amused. 'Jumbo must weigh a few tons,' said a policeman afterwards, 'so it was fortunate that we didn't have to carry him. Of course, we should arrest him, but as he has a good record, we shall let him off this time.' New words and expressions 生词和短语 versus prep. Christmas n. circus n. present n. accompany v. approach v. ought modal verb. weigh v. fortunate adj. 参考译文 去年圣诞节，马戏团老板吉米.盖茨决定送些礼物给儿童医院。他打扮成圣诞老人，在由6个漂亮姑娘组成的“仪仗队”的陪同下，骑上一头名叫江伯的小象，沿着城里的主要街道出发了。他本该知道警察绝不会允许这类事情发生。一个警察走过来告诉吉米，他应该走一条小路，因为江泊阻碍了交通。虽然吉米同意马上就走，但江伯却拒绝移动。15个警察不得不用很大的力气把它推离主要街道。警察虽然吃了苦头，但他们还是感到很有趣。“江伯一定有好几吨重，”一个警察事后这样说，“值得庆幸的是它没让我们抬它走。当然，我们应该逮捕它，但由于它一贯表现很好，这次我们饶了它。” Lesson 66 Sweet as honey! 像蜜一样甜！ First listen and then answer the question. 听录音，然后回答以下问题。 What was 'sweet as honey' and why? In 1963 a Lancaster bomber crashed on Wallis Island, a remote place in the South Pacific, a long way west of Samoa. The plane wasn't too badly damaged, but over the years, the crash was forgotten and the wreck remained undisturbed. Then in 1989, twenty-six years after the crash, the plane was accidentally rediscovered in an aerial survey of the island. By this time, a Lancaster bomber in reasonable condition was rare and worth rescuing. The French authorities had the plane packaged and moved in parts back to France. Now a group of enthusiasts are going to have the plane restored. It has four Rolls-Royce Merlin engines, but the group will need to have only three of them rebuilt. Imagine their surprise and delight when they broke open the packing cases and found that the fourth engine was sweet as honey -- still in perfect condition. A colony of bees had turned the engine into a hive and it was totally preserved in beeswax! New words and expressions 生词和短语 Lancaster n. 兰开斯特 bomber n. 轰炸机 remote adj. 偏僻的 Pacific n. 太平洋 damage v. 毁坏 wreck n. 残骸 rediscover v. 重新发现 aerial adj. 航空的 survey n. 调查 rescue v. 营救 package v. 把......打包 enthusiast n. 热心人 restore v. 修复 imagine v. 想像 packing case 包装箱 colony n. 群 bee n. 蜂 hive n. 蜂房 preserve v. 保护 beeswax n. 蜂蜡 参考译文 1963年，一架兰开斯特轰炸机在瓦立斯岛毁。那是南太洋中一个很偏僻的小岛，位于萨摩亚群岛以西，距离群岛还有很长一段距离。飞机损坏的程度并不严重，但是，多年来这起飞机失事已被遗忘，飞机残骸也没受到破坏。于是，到了1989年，飞机失事26年后，在对小岛的一次航空勘查中那架飞机被意外地发现了。到了那个时候，状况良好的兰开斯特轰炸机实属罕见，值得抢救。法国政府让人把飞机包装起来，一部分一部分地搬回法国。一群热心人计划修复这架飞机。该飞机装装配有4台罗尔斯-罗伊斯的默林发动机，但是他们只需要修复其中的3台。想一想他们所感受到的惊奇和兴奋 —— 当他们拆开包装箱时，他们发现第4台发动机就像蜂蜜一样甜 —— 发动机完好无损。一群蜜蜂把发动机当作了蜂房，发动机在蜂蜡中被完整地保存了下来。 Lesson 67 Volcanoes 火山 First listen and then answer the question. 听录音，然后回答以下问题。 Why does Tazieff risk his life like this? Haroun Tazieff, the Polish scientist, has spent his lifetime studying active volcanoes and deep caves in all parts of the world. In 1948, he went to Lake Kivu in the Congo to observe a new volcano which he later named Kituro. Tazieff was able to set up his camp very close to the volcano while it was erupting violently. Though he managed to take a number of brilliant photographs, he could not stay near the volcano for very long. He noticed that a river of liquid rock was coming towards him. It threatened to surround him completely, but Tazieff managed to escape just in time. He waited until the volcano became quiet and he was able to return two days later. This time, he managed to climb into the mouth of Kituro so that he could take photographs and measure temperatures. Tazieff has often risked his life in this way. He has been able to tell us more about active volcanoes than any man alive. New words and expressions 生词和短语 volcano n. 火山 active adj. 活动的 Kivu n. 基伍湖 Congo n. 刚果 Kituro n. 基图罗 erupt v. （火山）喷发 violently adv. 猛烈地，剧烈地 manage v. 设法 brilliant adj. 精彩的 liquid adj. 液态的 escape v. 逃脱 alive adj. 活着的 参考译文 波兰科学家哈罗恩.塔捷耶夫花了毕生的精力来研究世界各地的活火山和探洞。1948年他去了刚果的基伍湖，对一座后来被他命名为基图罗的新火山进行观察。当火山正在猛烈地喷发时，塔捷耶夫有办法把帐篷搭在离它非常近的地方。尽管他设法拍了一些十分精彩的照片，但他却不能在火山附近停留太长的时间。他发现有一股岩浆正向他流过来，眼看就要将他团团围住，但塔捷耶夫还是设法及时逃离了。他等到火山平静下来，两天以后又返回去。这次他设法爬进了基图罗火山口，以便能拍摄照片和测试温度。塔捷耶夫经常冒这样的生命危险。他能告诉我们的有关活火山的情况比任何在世的人都要多。 Lesson 68 Persistent 纠缠不休 First listen and then answer the question. 听录音，然后回答以下问题。 Why did Elizabeth tell Nigel that she was going to the dentist? I crossed the street to avoid meeting him, but he saw me and came running towards me. It was no use pretending that I had not seen him, so I waved to him. I never enjoy meeting Nigel Dykes. He never has anything to do. No matter how busy you are, he always insists on coming with you. I had to think of a way of preventing him from following me around all morning. 'Hello, Nigel,' I said. 'Fancy meeting you here!' 'Hi, Elizabeth,' Nigel answered. 'I was just wondering how to spend the morning -- until I saw you. You're not busy doing anything, are you?' 'No, not at all,' I answered. 'I'm going to...' 'Would you mind my coming with you?' he asked, before I had finished speaking. 'Not at all,' I lied, 'but I'm going to the dentist.' 'Then I'll come with you,' he answered. 'There's always plenty to read in the waiting room! New words and expressions 生词和短语 persistent adj. 坚持的，固执的 avoid v. 避开 insist v. 坚持做 参考译文 我穿过马路以便避开他，但他看到我并朝我跑过来。若再装作没看见他已是没有用了，我只好向他招手。我就怕遇到奈杰尔.戴克斯。他从来都是无事可做，不管你多忙，他总是坚持要跟你去。我得想办法不让他整个上午缠着我。 “你好，奈杰尔，想不到在这儿见到你。”我说。 “你好，伊丽莎白，”奈杰尔回答说，“我正不知道怎么消磨这一上午呢，正好见到好。你不忙，是吗？” “不，不忙，我打算去......”我回答。 “我跟你一道去行吗？”没等我说完话他就问道。 “没关系，但我准备去牙医那里。”我说了个谎。 “那我也跟你去，候诊室里总有很多东西可供阅读！”他回答。 Lesson 69 But not murder! 并非谋杀！ First listen and then answer the question. 听录音，然后回答以下问题。 Do you think that the writer passed his driving test? Why? I was being tested for a driving licence for the third time. I had been asked to drive in heavy traffic and had done so successfully. After having been instructed to drive out of town, I began to acquire confidence. Sure that I had passed, I was almost beginning to enjoy my test. The examiner must have been pleased with my performance, for he smiled and said. 'Just one more thing, Mr.Eames. Let us suppose that a child suddenly crosses the road in front of you. As soon as I tap on the window, you must stop within five feet.' I continued driving and after some time, the examiner tapped loudly, Though the sound could be heard clearly, it took me a long time to react. I suddenly pressed the brake pedal and we were both thrown forward. The examiner looked at me sadly. 'Mr.Eames,' he said, in a mournful voice, 'you have just killed that child!' New words and expressions 生词和短语 murder n. 谋杀 instruct v. 命令，指示 acquire v. 取得，获得 confidence n. 信心 examiner n. 主考人 suppose v. 假设 tap v. 轻敲 react v. 反应 brake n. 刹车 pedal n. 踏板 mournful adj. 悲哀的 参考译文 我第3次接受驾驶执照考试。按照要求在车辆拥挤的路上驾驶，我圆满地完成了。在接到把车开出城的指令后，我开始有了信心。确信我已通过考试，所以我几乎开始喜欢起这次考试。主考人对我的驾驶想必是满意的，因为他微笑着说：“埃姆斯先生，只剩1项了。让我们假设一个小孩子突然在你前面穿过马路。我一敲车窗，你必须把车停在5英尺之内。”我继续往前开着。过了一会儿，主考人砰砰地敲了起来。虽然声音听得很清楚，但我过了好一会儿才作出反应。我突然用力踩紧刹车踏板，结果我俩的身体都向前冲去。主考人伤心地看着我。“埃姆斯先生，”他以悲伤的声调说，“你刚刚把那个小孩压死了！” Lesson 70 Red for danger 危险的红色 First listen and then answer the question. 听录音，然后回答以下问题。 How was the drunk removed from the ring? During a bullfight, a drunk suddenly wandered into the middle of the ring. The crowd began to shout, but the drunk was unaware of the danger. The bull was busy with the matador at the time, but it suddenly caught sight of the drunk who was shouting rude remarks and waving a red cap. Apparently sensitive to criticism, the bull forgot all about the matador and charged at the drunk. The crowd suddenly grew quiet. The drunk, however, seemed quite sure of himself. When the bull got close to him, he clumsily stepped aside to let it pass. The crowd broke into cheers and the drunk bowed. By this time, however, three men had come into the ring and they quickly dragged the drunk to safety. Even the bull seemed to feel sorry for him, for it looked on sympathetically until the drunk was out of the way before once more turning its attention to the matador. New words and expressions 生词和短语 bullfight n. 斗牛 drunk n. 醉汉 wander v. 溜达，乱走 ring n. 圆形竞技场地 unaware adj. 不知道的，未觉察的 bull n. 公牛 matador n. 斗牛士 remark n. 评论；言语 apparently adv. 明显地 sensitive adj. 敏感的 criticism n. 批评 charge v. 冲上去 clumsily adv. 笨拙地 bow v. 鞠躬 safety n. 安全地带 sympathetically adv. 同情地 参考译文 在一次斗牛时，一个醉汉突然溜达到斗牛场中间，人们开始大叫起来，但醉汉却没有意识到危险。当时那公牛正忙于对付斗牛士，但突然它看见了醉汉，只见他正大声说着粗鲁的话，手里挥动着一顶红帽子。对挑衅显然非常敏感的公牛完全撇开斗牛士，直奔醉汉而来。观众突然静了下来，可这醉汉像是很有把握似的。当公牛逼近他时，他踉跄地住旁边一闪，牛扑空了。观众欢呼起来，醉汉向人们鞠躬致谢。然而，此时已有3个人进入斗牛场，迅速把醉汉拉到安全的地方。好像连牛也在为他感到遗憾，因为它一直同情地看着醉汉，直到他的背影消逝，才重新将注意力转向斗牛士。 Lesson 71 A famous clock 一个著名的大钟 First listen and then answer the question. 听录音，然后回答以下问题。 Has Big Ben ever gone wrong? When you visit London, one of the first things you will see is Big Ben, the famous clock which can be heard all over the world on the B.B.C. If the Houses of Parliament had not been burned down in 1834, the great clock would never have been erected. Big Ben takes its name from Sir Benjamin Hall who was responsible for the making of the clock when the new Houses of Parliament were being built. It is not only of immense size, but is extremely accurate as well. Officials from Greenwich Observatory have the clock checked twice a day. On the B.B.C. you can hear the clock when it is actually striking because microphones are connected to the clock tower. Big Ben has rarely gone wrong. Once, however, it failed to give the correct time. A painter who had been working on the tower hung a pot of paint on one of the hands and slowed it down! New words and expressions 生词和短语 parliament n. 议会，国会 erect v. 建起 accurate adj. 准确的 official n. 官员，行政人员 Greenwich n. 格林尼治 observatory n. 天文台 check v. 检查 microphone n. 扩音器，麦克风 tower n. 塔 参考译文 当你游览伦敦时，首先看到的东西之一就是“大本”钟，即那座从英国广播公司的广播中全世界都可以听到它的声音的著名大钟。如果不是国会大厦在1834年被焚毁的话，这座大钟永远也不会建造。“大本”钟得名于本杰明.霍尔爵士，因为当建造新的国会大厦时，他负责建造大钟。此钟不仅外型巨大，而且走时也非常准确。格林尼治天文台的官员们每天两次派人矫正此钟。当大钟打点的时候，你可以从英国广播公司的广播中听到，因为钟塔上接了麦克风。“大本”钟很多出差错。然而有一次，它却把时间报错。在钟塔上干活的一位油漆工把一只油漆桶挂在了一根指针上，把钟弄慢了！ Lesson 72 A car called bluebird “蓝鸟”汽车 First listen and then answer the question. 听录音，然后回答以下问题。 What mistake was made? The great racing driver, Sir Malcolm Campbell, was the first man to drive at over 300 miles per hour. He set up a new world record in September 1935 at Bonneville Salt Flats, Utah. Bluebird, the car he was driving, had been specially built for him. It was over 30 feet in length and had a 2,500-horsepower engine. Although Campbell reached a speed of over 304 miles per hour, he had great difficulty in controlling the car because a tyre burst during the first run. After his attempt, Campbell was disappointed to learn that his average speed had been 299 miles per hour. However, a few days later, he was told that a mistake had been made. His average speed had been 301 miles per hour. Since that time, racing drivers have reached speeds over 600 miles an hour. Following in his father's footsteps many years later, Sir Malcolm's son, Donald, also set up a world record. Like his father, he was driving a car called Bluebird. New words and expressions 生词和短语 racing n. 竞赛 per prep. 每 Utah n. 犹他（美国州名） horsepower n. 马力 burst v. 爆裂 average adj. 平均的 footstep n. 足迹 参考译文 杰出的赛车选手马尔科姆.坎贝尔爵士是第一个以每小时超过300英里的速度驾车的人。他于1935年9月在犹他州的邦纳维尔盐滩创造了一项新的世界纪录。他驾驶的“蓝鸟”牌汽车是专门为他制造的。它的车身长30英尺，有一个2,500 马力的发动机。尽管坎贝尔达到了每小时超过304英里的速度，但他很难把汽车控制住，因为在开始的行程中爆了一只轮胎。比赛结束后，坎贝尔非常失望地得知他的平均时速是299英里。然而，几天之后，有人告诉他说弄错了。他的平均时速实际是301英里。从那时以来，赛车选手已达到每小时600英里的速度。很多年之后，马尔科姆爵士的儿子唐纳德踏着父亲的足迹，也创造了一项世界纪录。同他父亲一样，他也驾驶着一辆名叫“蓝鸟”的汽车。 Lesson 73 The record-holder 纪录保持着 First listen and then answer the question. 听录音，然后回答以下问题。 Did the boy go where he wanted to? Children who play truant from school are unimaginative. A quiet day's fishing, or eight hours in a cinema seeing the same film over and over again, is usually as far as they get. They have all been put to shame by a boy who, while playing truant, travelled 1,600 miles. He hitchhiked to Dover and, towards evening, went into a boat to find somewhere to sleep. When he woke up next morning, he discovered that the boat had, in the meantime, travelled to Calais. No one noticed the boy as he crept off. From there, he hitchhiked to Paris in a lorry. The driver gave him a few biscuits and a cup of coffee and left him just outside the city. The next car the boy stopped did not take him into the centre of Paris as he hoped it would, but to Perpignan on the French-Spanish border. There he was picked up by a policeman and sent back to England by the local authorities. He has surely set up a record for the thousands of children who dream of evading school. New words and expressions 生词和短语 record-holder 纪录保持者 truant n. 逃学的孩子 unimaginative adj. 缺乏想像力的 shame n. 惭愧，羞耻 hitchhike v. 搭便车旅行 meantime n. 其间 lorry n. 卡车 border n. 边界 evade v. 逃避，逃离 参考译文 逃学的孩子们都缺乏想像力。他们通常能够做到的，至多也就是安静地钓上一天鱼，或在电影院里坐上8个小时，一遍遍地看同一部电影。而有那么一个小男孩，他在逃学期间旅行了1,600英里，从而使上述所有逃学的孩子们都相形见绌了。他搭便车到了多佛，天快黑时钻进了一条船，想找个地方睡觉。第二天早上他醒来时，发现船在这段时间已经到了加。当男孩从船里爬出来时，谁也没有发现他。从那里他又搭上卡车到了巴黎。司机给了他几块饼干和一杯咖啡，就把他丢在了城外。男孩截住的下一辆车，没有像他希望的那样把他带到巴黎市中心，而是把他带到了法国和西班牙边界上的佩皮尼昂。他在那儿被一个警察抓住了，之后被当局送回了英国。他无疑为成千上万梦想逃避上学的孩子们创造了一项纪录。 Lesson 74 Out of the limelight 舞台之外 First listen and then answer the question. 听录音，然后回答以下问题。 Why was their disguise 'too perfect'? An ancient bus stopped by a dry river bed and a party of famous actors and actresses got off. Dressed in dark glasses and old clothes, they had taken special precautions so that no one should recognize them. But as they soon discovered, disguises can sometimes be too perfect. 'This is a wonderful place for a picnic,' said Gloria Gleam. 'It couldn't be better, Gloria,' Brinksley Meers agreed. 'No newspaper men, no film fans! Why don't we come more often?' Meanwhile, two other actors, Rockwall Slinger and Merlin Greeves, had carried two large food baskets to a shady spot under some trees. When they had all made themselves comfortable, a stranger appeared. He looked very angry. 'Now you get out of here, all of you!' he shouted. 'I'm sheriff here. Do you see that notice? It says "No Camping" -- in case you can't read!' 'Look, sheriff,' said Rockwall, 'don't be too hard on us. I'm Rockwall Slinger and this is Merlin Greeves.' 'Oh, is it?' said the sheriff with a sneer. 'Well, I'm Brinksley Meers, and my other name is Gloria Gleam. Now you get out of here fast!' New words and expressions 生词和短语 limelight n. 舞台灯光 precaution n. 预防措施 fan n. 狂热者，迷 shady adj. 遮荫的 sheriff n. 司法长官 notice n. 告示 sneer n. 冷笑 参考译文 一辆古旧的汽车停在一条干涸的河床边，一群著名男女演员下了车。他们戴着墨镜，穿着旧衣裳，特别小心以防别人认出他们。但他们很快就发觉，化装的效果有时过分完美了。 “在这个地方野餐简直太妙了，”格格利亚.格利姆说。 “是再好不过的了，格格利亚。”布林克斯利.米尔斯表示同意，“没有记者，没有影迷！我们为什么不经常来这里呢？” “此时，另外两位演员，罗克沃尔.斯林格和默林.格里夫斯，已经把两个大食品篮子提到了一片树荫下。当他们都已安排舒适时，一个陌生人出现了。他看上去非常气愤。“你们都从这里走开，全都走开！”他大叫着，“我是这里的司法长官。你们看到那个布告牌了吗？上面写着‘禁止野营’－－除非你们不识字！” “好了，好了，司法官，”罗克沃尔说，“别使我们难堪。我是罗克沃尔.斯林格，这位是默林.格里夫斯。” “噢，是吗？”那位司法长官冷笑一声说道，“好，我就是布林克斯利.米尔斯。我还有一个名字叫格格利亚.格利姆。现在你们赶快滚吧！” Lesson 75 SOS 呼救信号 First listen and then answer the question. 听录音，然后回答以下问题。 How did the woman get help? When a light passenger plane flew off course some time ago, it crashed in the mountains and its pilot was killed. The only passengers, a young woman and her two baby daughters, were unhurt. It was the middle of winter. Snow lay thick on the ground. The woman knew that the nearest village was miles away. When it grew dark, she turned a suitcase into a bed and put the children inside it, covering them with all the clothes she could find. During the night, it got terribly cold. The woman kept as near as she could to the children and even tried to get into the case herself, but it was too small. Early next morning, she heard planes passing overhead and wondered how she could send a signal. Then she had an idea. She stamped out the letters 'SOS' in the snow. Fortunately, a pilot saw the signal and sent a message by radio to the nearest town. It was not long before a helicopter arrived on the scene to rescue the survivors of the plane crash. New words and expressions 生词和短语 thick adj. 厚的 signal n. 信号 stamp v. 跺，踩 helicopter n. 直升飞机 scene n. 现场 survivor n. 幸存者 参考译文 不久前，一架轻型客机偏离了航线，在山区坠毁，飞行员丧生。机上仅有的乘客，一位年轻的妇女和她的两个女婴却平安无事。此时正值隆冬季节，地上积着厚厚的雪。这位妇女知道，即使最近的村庄也有数英里远。天黑下来的时候，她把提箱当作小床，把两个孩子放了进去，又把所有能找到的衣服都盖在了孩子们身上。夜里，天冷得厉害。这位妇女尽可能地靠近孩子，甚至自己也想钻进箱子里去，只是箱子太小了。第二天一大早，她听到头顶上有飞机飞过，但不知道怎样才能发个信号。后来她有了一个主意。她在雪地上踩出了“SOS”这3个字母。幸运得很，一位飞行员看到这个信号，用无线电给最近的城镇发了报。不久，一架直升飞机飞抵飞机失事现场，来搭救这几个幸存者。 Lesson 76 April Fools' Day 愚人节 First listen and then answer the question. 听录音，然后回答以下问题。 What was the joke? 'To end our special news bulletin,' said the voice of the television announcer, 'we're going over to the macaroni fields of Calabria. Macaroni has been grown in this area for over six hundred years. Two of the leading growers, Giuseppe Moldova and Riccardo Brabante, tell me that they have been expecting a splendid crop this year and harvesting has begun earlier than usual. Here you can see two workers who, between them, have just finished cutting three cartloads of golden brown macaroni stalks. The whole village has been working day and night gathering and threshing this year's crop before the September rains. On the right, you can see Mrs. Brabante herself. She has been helping her husband for thirty years now. Mrs. Brabante is talking to the manager of the local factory where the crop is processed. This last scene shows you what will happen at the end of the harvest: the famous Calabrian macaroni-eating competition! Signor Fratelli, the present champion, has won it every year since 1991. And that ends our special bulletin for today, Thursday, April lst. We're now going back to the studio.' New words and expressions 生词和短语 fool n. 傻瓜 bulletin n. 新闻简报 announcer n. （电视、电台）播音员 macaroni n. 通心面，空心面条 leading adj. 主要的 grower n. 种植者 splendid adj. 极好的 stalk n. 梗 gather v. 收庄稼 thresh v. 打（庄稼） process v. 加工 Signor n. （意大利语）先生 present adj. 目前的 champion n. 冠军 studio n. 播音室 参考译文 “作为我们专题新闻节目的结尾，”电视广播员说，“我们现在到克拉布利亚的通心粉田里。通心粉在这个地区已经种植了600多年了。两个主要种植者，朱塞皮.莫尔道瓦和里卡多.布拉班特告诉我，他们一直期待着今年获得一个大丰收，收割工作比往年开始要早些。这里您可以看到两个工人，他们协力割下了3车金黄色的通心粉秸。全村的人都日夜奋战，要赶在9月的雨季之前把今年的庄稼收获上来，打完场。在屏幕的右侧，您可以看到布拉班特太太本人，她已经帮了她的丈夫30年了。布拉班特太太现在正和负责通心粉加工的当地加工厂的经理交谈。这最后一个镜头向您展示了收获之后将发生的事情：著名的克拉布利亚人吃通心粉大赛！目前的冠军弗拉特里先生，自1991年以来，年年获胜。今天 -- 4月1日，星期四--的专题新闻节目到此结束。现在我们回到电视演播室。” Lesson 77 A successful operation 一例成功的手术 First listen and then answer the question. 听录音，然后回答以下问题。 Did the doctors find out how the woman died? The mummy of an Egyptian woman who died in 800 B.C. has just had an operation. The mummy is that of Shepenmut who was once a singer in the Temple of Thebes. As there were strange marks on the X-ray plates taken of the mummy, doctors have been trying to find out whether the woman died of a rare disease. The only way to do this was to operate. The operation, which lasted for over four hours, proved to be very difficult because of the hard resin which covered the skin. The doctors removed a section of the mummy and sent it to a laboratory. They also found something which the X-ray plates did not show: a small wax figure of the god Duamutef. This god which has the head of a cow was normally placed inside a mummy. The doctors have not yet decided how the woman died. They feared that the mummy would fall to pieces when they cut it open, but fortunately this has not happened. The mummy successfully survived the operation. New words and expressions 生词和短语 mummy n. 木乃伊 Egyptian adj. 埃及的 temple n. 庙 mark n. 斑点 plate n. （照相）底片 disease n. 疾病 last v. 持续 prove v. 显示出 resin n. 树脂 skin n. 皮肤 section n. 切片 figure n. （人的）体形；人像 normally adv. 通常地 survive v. 幸免于 参考译文 死于公元前800年的一位埃及妇女的木乃伊刚刚接受了一次手术。这是曾在底比斯神殿里当过歌手的赛潘姆特的木乃伊。由于在给这个木乃伊拍摄的X光片子上有点奇怪的斑点，所以，医生们一直试图搞清这位妇女是否死于一种罕见的疾病。搞清的唯一办法就是手术。手术持续了4个多小时，非常难做，因为皮肤上覆盖着一层硬硬的树脂。医生们从木乃伊身上取下一个切片，送去化验。他们还发现了X光片所没有显示的东西：一个蜡制的杜瓦木特夫神小塑像。这种牛头人身的神像通常被放在木乃伊体内。医生们至今还未确定这位妇女的死因。他们曾担心在把木乃伊切开后，它会散成碎片，但幸运得很，这种情况并未发生。这具木乃伊成功地经受了这次手术。 Lesson 78 The last one? 最后一枝吗？ First listen and then answer the question. 听录音，然后回答以下问题。 For how long did the writer give up smoking? After reading an article entitled 'Cigarette Smoking and Your Health' I lit a cigarette to calm my nerves. I smoked with concentration and pleasure as I was sure that this would be my last cigarette. For a whole week I did not smoke at all and during this time, my wife suffered terribly. I had all the usual symptoms of someone giving up smoking: a bad temper and an enormous appetite. My friends kept on offering me cigarettes and cigars. They made no effort to hide their amusement whenever I produced a packet of sweets from my pocket. After seven days of this I went to a party. Everybody around me was smoking and I felt extremely uncomfortable. When my old friend Brian urged me to accept a cigarette, it was more than I could bear. I took one guiltily, lit it and smoked with satisfaction. My wife was delighted that things had returned to normal once more. Anyway, as Brian pointed out, it is the easiest thing in the world to give up smoking. He himself has done it lots of times! New words and expressions 生词和短语 entitle v. 以......为名 calm v. 使镇定 nerve n. 神经 concentration n. 集中，专心 suffer v. 受苦，受害 symptom n. 症状 temper n. 脾气 appetite n. 胃口，食欲 produce v. 拿出 urge v. 力劝，怂恿 satisfaction n. 满意，满足 delighted adj. 欣喜的 参考译文 读完一篇题为《吸烟与健康》的文章之后，我点上了一枝香烟，来镇定一下自己紧张的神经。我聚精会神而又愉快地吸着这枝烟。因为我确信这是我最后一枝烟了。整整一个星期我根本没有吸烟。在此期间，我妻子吃尽了苦头。我具备了戒烟者通常表现出来的所有症状：脾气暴躁和食欲旺盛。我的朋友们不断地向我递香烟和雪茄。每当我从口袋里掏出一包糖果时，他们都毫不掩饰地表现出他们对此感到非常好笑。这样过了7天以后，我去参加一次聚会。我周围的每个人都在吸烟，我感到非常不自在。当我的老朋友布赖恩极力劝我接受一枝香烟时，我再也忍不住了。我内疚地接过一枝点上，心满意足地抽起来。一切又都恢复了正常，为此我妻子十分高兴。不管怎么说，正如布赖恩指出的那样，戒烟是世界上最容易的事情，他自己就已戒了很多次了！ Lesson 79 By air 乘飞机 First listen and then answer the question. 听录音，然后回答以下问题。 Why did the plane turn back? I used to travel by air a great deal when I was a boy. My parents used to live in South America and I used to fly there from Europe in the holidays. A flight attendant would take charge of me and I never had an unpleasant experience. I am used to traveling by air and only on one occasion have I ever felt frightened. After taking off, we were flying low over the city and slowly gaining height, when the plane suddenly turned round and flew back to the airport. While we were waiting to land, a flight attendant told us to keep calm and to get off the plane quietly as soon as it had touched down. Everybody on board was worried and we were curious to find out what had happened. Later we learnt that there was a very important person on board. The police had been told that a bomb had been planted on the plane. After we had landed, the plane was searched thoroughly. Fortunately, nothing was found and five hours later we were able to take off again. New words and expressions 生词和短语 parent n. 父（母）亲 flight attendant 空中乘务员 frightened adj. 害怕，担惊 curious adj. 急于了解，好奇的 bomb n. 炸弹 plant v. 安放 参考译文 我在幼年的时候，曾多次乘飞机旅行。我的父母曾经住在南美洲，所以假期里我常从欧洲乘飞机到他们那里。我总是由一位空中乘务员照管，从未遇到过不愉快的经历。我习惯了乘飞机旅行，只是有一次把我吓坏了。起飞之后，我们在城市上空低低地飞行，然后慢慢爬高。这时飞机突然调转头来，飞回了机场。在我们等待降落时，一位空中乘务员告诉我们要保持镇静，待飞机一着陆，就马上不声不响地离开飞机。飞机上的人都很着急，大家都急于想知道究竟出了什么事。后来我们才得知，飞机上坐了一位非常重要的人物。有人报告警察，说飞机上安放了一枚炸弹。我们降落之后，飞机被彻底搜查了一遍。幸运的是，什么也没有找到。5个小时后，我们又起飞了。 Lesson 80 The Crystal Palace 水晶宫 First listen and then answer the question. 听录音，然后回答以下问题。 How many people visited the Great Exhibition of 1851? Perhaps the most extraordinary building of the nineteeth century was the Crystal Palace, which was built in Hyde Park for the Great Exhibition of 1851. The Crystal Palace was different from all other buildings in the world, for it was made of iron and glass. It was one of the biggest buildings of all time and a lot of people from many countries came to see it. A great many goods were sent to the exhibition from various parts of the world. There was also a great deal of machinery on display. The most wonderful piece of machinery on show was Nasmyth's steam hammer. Though in those days, traveling was not as easy as it is today, steam boats carried thousands of visitors across the Channel from Europe. On arriving in England, they were taken to the Crystal Palace by train. There were six million visitors in all, and the profits from the exhibition were used to build museums and colleges. Later, the Crystal Palace was moved to South London. It remained one of the most famous buildings in the world until it was burnt down in 1936. New words and expressions 生词和短语 palace n. 宫殿 extraordinary adj. 不平常的，非凡的 exhibition n. 展览 iron n. 铁 various adj. 各种各样的 machinery n. 机器 display n. 展览 steam n. 蒸汽 profit n. 利润 college n. 学院 参考译文 19世纪最不寻常的建筑也许要数水晶宫了，它是为1851年的“世界博览会”而建在海德公园的。这座水晶宫不同于世界上所有的其他建筑，因为它是用钢和玻璃建成的。它是有史以来最高大的建筑物之一，因此，人们从各个国家纷纷前来参观。大量的商品从世界各地运送到了博览会，参展的还有很多机器，其中最奇妙的是内史密斯的蒸汽锤。尽管在当时旅行不像现在这么容易，但汽船还是把成千上万的参观者从欧洲大陆送过了英吉利海峡。一到英国，火车就把他们送到了水晶宫。参观的人数总共是600万。博览会的赢利用来建造博物馆和高等学校。后来，“水晶宫”被移到了伦敦南部。在1936年被焚毁之前，它一直是世界上最著名的建筑物之一。 Lesson 81 Escape 脱逃 First listen and then answer the question. 听录音，然后回答以下问题。 Why did the prisoner attack the driver? When he had killed the guard, the prisoner of war quickly dragged him into the bushes. Working rapidly in the darkness, he soon changed into the dead man's clothes. Now, dressed in a blue uniform and with a rifle over his shoulder, the prisoner marched boldly up and down in front of the camp. He could hear shouting in the camp itself. Lights were blazing and men were running here and there: they had just discovered that a prisoner had escaped. At that moment, a large black car with four officers inside it, stopped at the camp gates. The officers got out and the prisoner stood to attention and saluted as they passed. When they had gone, the driver of the car came towards him. The man obviously wanted to talk. He was rather elderly with grey hair and clear blue eyes. The prisoner felt sorry for him, but there was nothing else he could do. As the man came near, the prisoner knocked him to the ground with a sharp blow. Then, jumping into the car, he drove off as quickly as he could. New words and expressions 生词和短语 prisoner n. 囚犯 bush n. 灌木丛 rapidly adv. 迅速地 uniform n. 制服 rifle n. 来福枪，步枪 shoulder n. 肩 march v. 行进 boldly adv. 大胆地 blaze v. 闪耀 salute v. 行礼 elderly adj. 上了年纪的 grey adj. 灰白的 sharp adj. 猛烈的 blow n. 打击 参考译文 那个战俘杀死卫兵以后，迅速地把尸体拖进了灌木丛。他在黑暗中忙活了一阵儿，很快就换上了死者的衣服。现在他身穿蓝军装，肩扛步枪，在军营门前大胆地来回走看。他听得军营里面的喧闹声。那里灯米通明，人们在东奔西跑：他们刚刚发现有一个俘虏跑了。正在此时，一辆黑色大轿车在军营门口停了下来。里面坐了4个军官。军官们下了车，战俘立正站好，并在他们从他面前经过时敬了礼。他们走后，汽车司机向他走来，这人显然是想聊天。他上了年纪，有着灰白的头发和明亮的蓝眼睛。战俘为他感到惋惜，但却没有别的选择。当这个人走近时，战俘一拳把他打倒在地，然后跳进车里，以最快的速度把车开走了。 Lesson 82 Monster or fish? 是妖还是鱼？ First listen and then answer the question. 听录音，然后回答以下问题。 What was the monster called? Fishermen and sailors sometimes claim to have seen monsters in the sea. Though people have often laughed at stories told by seamen, it is now known that many of these 'monsters' which have at times been sighted are simply strange fish. Occasionally, unusual creatures are washed to the shore, but they are rarely caught out at sea. Some time ago, however, a peculiar fish was caught near Madagascar. A small fishing boat was carried miles out to sea by the powerful fish as it pulled on the line. Realizing that this was no ordinary fish, the fisherman made every effort not to damage it in any way. When it was eventually brought to shore, it was found to be over thirteen feet long. It had a head like a horse, big blue eyes, shining silver skin, and a bright red tail. The fish, which has since been sent to a museum where it is being examined by a scientist, is called an oarfish. Such creatures have rarely been seen alive by man as they live at a depth of six hundred feet. New words and expressions 生词和短语 monster n. 怪物 sailor n. 海员 sight v. 见到 creature n. 动物，生物 peculiar adj. 奇怪的，不寻常的 shining adj. 闪闪发光的 oarfish n. 桨鱼 参考译文 渔夫和水手们有时声称自己看到过海里的妖怪。虽然人们常常对水手们讲的故事付诸一笑，但现在看来，人们有时看到的这些“妖怪”很多不过是些奇怪的鱼。一些异常的生物偶尔会被冲到岸上来，但它们在海上却极少能被捕到。然而不久前，在马达加斯加附近的海里却捕到了一条奇怪的鱼。一条小渔船被一条咬住钩的强壮的大鱼拖到了几英里以外的海面上。那位渔民意识到这根本不是一条普通的鱼，于是千方百计不让它受到丝毫伤害。当终于把它弄上岸后，人们发现它身长超过了13英尺。它长着一个像马一样的头，有着大的蓝眼睛和闪闪发光的银色皮肤，还有一条鲜红色的尾巴。此鱼叫桨鱼，被送进了博物馆，现正接受一位科学家的检查。人们很少能看到活着的这类动物，因为它们生活在600英尺深的水下。 Lesson 83 After the elections 大选之后 First listen and then answer the question. 听录音，然后回答以下问题。 Why did Patrick keep on asking the same question? The former Prime Minister, Mr. Wentworth Lane, was defeated in the recent elections. He is now retiring from political life and has gone abroad. My friend, Patrick, has always been a fanatical opponent of Mr. Lane's Radical Progressive Party. After the elections, Patrick went to the former Prime Minister's house. When he asked if Mr. Lane lived there, the policeman on duty told him that since his defeat, the ex-Prime Minister had gone abroad. On the following day, Patrick went to the house again. The same policeman was just walking slowly past the entrance, when Patrick asked the same question. Though a little suspicious this time, the policeman gave him the same answer. The day after, Patrick went to the house once more and asked exactly the same question. This time, the policeman lost his temper. 'I told you yesterday and the day before yesterday,' he shouted, 'Mr. Lane was defeated in the elections. He has retired from political life and gone to live abroad!" 'I know,' answered Patrick, 'but I love to hear you say it!' New words and expressions 生词和短语 election n. 选举 former adj. 从前的 defeat v. 打败 fanatical adj. 狂热的 opponent n. 反对者，对手 radical adj. 激进的 progressive adj. 进步的 ex- prefix （前缀，用于名词前）前...... suspicious adj. 怀疑的 参考译文 前首相温特沃兹.莱恩先生在最近的大选中被击败。他现在退出了政界，到国外去了。我的朋友帕特里克一直是莱恩先生的激进党的强烈反对者。大选结束后，帕特里克来到了前首相的住处。当他询问莱恩先生是否住在那里时，值班的警察告诉他这位前首相落选后出国去了。第二天，帕特里克再次来到首相的住处。昨天的那位警察正从门口慢慢走过，帕特里克上前问了和昨天同样的问题。虽然那位警察这次有点疑心，但还是对他作了同样的回答。第三天，帕特里克又去了，提出了同前两天完全一样的问题。这一次警察火了。“我昨天和前天都告诉过您了，”他大叫着，“莱恩先生在大选中被击败了，他已经退出了政界去国外了！” “这我都知道，”帕特里克说，“可我就是喜欢听你说出这此！” Lesson 84 On strike 罢工 First listen and then answer the question. 听录音，然后回答以下问题。 Who will be driving the buses next week? Busmen have decided to go on strike next week. The strike is due to begin on Tuesday. No one knows how long it will last. The busmen have stated that the strike will continue until general agreement is reached about pay and working conditions. Most people believe that the strike will last for at least a week. Many owners of private cars are going to offer 'free rides' to people on their way to work. This will relieve pressure on the trains to some extent. Meanwhile, a number of university students have volunteered to drive buses while the strike lasts. All the students are expert drivers, but before they drive any of the buses, they will have to pass a special test. The students are going to take the test in two days' time. Even so, people are going to find it difficult to get to work. But so far, the public has expressed its gratitude to the students in letters to the Press. Only one or two people have objected that the students will drive too fast! New words and expressions 生词和短语 strike n. 罢工 busman n. 公共汽车司机 state v. 正式提出，宣布 agreement n. 协议 relieve v. 减轻 pressure n. 压力，麻烦 extent n. 程度 volunteer v. 自动提出，自愿 gratitude n. 感激 Press n. 新闻界 object v. 不赞成，反对 参考译文 公共汽车司机决定下星期罢工。罢工定于星期二开始，谁也不知道会持续多久。司机们声称此次罢工将一直持续到就工资和工作条件问题达成全面协议的时候为止。多数人认为此次罢工至少会持续一个星期。很多私人汽车的车主正准备为乘车上班的人们提供“免费乘车”的服务，这将在某种程度上减轻对火车的压力。与此同时，有一部分大学生自愿在罢工期间驾驶公共汽车。所有的学生都是开车的能手，但在驾驶公共汽车之前，他们必须通过一项专门测验。学生们准备在两天后就接受测验。即使这样，人们仍会感到上班有困难。但到目前为止，公众已经向新闻界写信表达他们对学生们的感激之情了。只有一两个人提出反对意见，说学生们会把车开得太快！ Lesson 85 Never too old to learn 活到老学到老 First listen and then answer the question. 听录音，然后回答以下问题。 How long has Mr. Page been teaching? I have just received a letter from my old school, informing me that my former headmaster, Mr. Stuart Page, will be retiring next week. Pupils of the school, old and new, will be sending him a present to mark the occasion. All those who have contributed towards the gift will sign their names in a large album which will be sent to the headmaster's home. We shall all remember Mr. Page for his patience and understanding and for the kindly encouragement he gave us when we went so unwillingly to school. A great many former pupils will be attending a farewell dinner in his honour next Thursday. It is a curious coincidence that the day before his retirement, Mr. Page will have been teaching for a total of forty years. After he has retired, he will devote himself to gardening. For him, this will be an entirely new hobby. But this does not matter, for, as he has often remarked, one is never too old to learn. New words and expressions 生词和短语 inform v. 告诉，通知 headmaster n. 校长 contribute v. 捐助，援助 gift n. 礼物，赠品 album n. 签名簿，相册 patience n. 耐心 encouragement n. 鼓励 farewell n. 告别 honour n. 敬意 coincidence n. 巧合 total n. 总数 devote v. 致力于 gardening n. 园艺 hobby n. 爱好，嗜好 参考译文 我刚刚收到母校的一封信，通知我说以前的校长斯图亚特.佩奇先生下星期就退休了。为了纪念这个日子，学校的学生——无论老同学还是新同学——将送他一件礼物。所有凑钱买此礼品的人都将自己的名字签在一本大签名簿上，签名簿将被送到校长的家里。我们不会忘记佩奇先生对我们既有耐心又充满理解，也不会忘记在我们不愿去上学时他给予我们的亲切鼓励。很多老同学都准备参加下星期四为他举行的告别宴会。佩奇先生退休的前一天正好是他执教满40年的日子，这真是奇妙的巧合。他退休后，将致力于园艺。对于他来说，这将是一种全新的爱好。但这没有关系，因为正如他常说的那样，人要活到老学到老。 Lesson 86 Out of control 失控 First listen and then answer the question. 听录音，然后回答以下问题。 What was the danger? As the man tried to swing the speedboat round, the steering wheel came away in his hands. He waved desperately to his companion, who had been water skiing for the last fifteen minutes. Both men had hardly had time to realize what was happening when they were thrown violently into the sea. The speedboat had struck a buoy, but it continued to move very quickly across the water. Both men had just begun to swim towards the shore, when they noticed with dismay that the speedboat was moving in a circle. It now came straight towards them at tremendous speed. In less than a minute, it roared past them only a few feet away. After it had passed, they swam on as quickly as they could because they knew that the boat would soon return. They had just had enough time to swim out of danger when the boat again completed a circle. On this occasion, however, it had slowed down considerably. The petrol had nearly all been used up. Before long, the noise dropped completely and the boat began to drift gently across the water. New words and expressions 生词和短语 swing v. 转向 speedboat n. 快艇 desperately adv. 绝望地 companion n. 同伙，伙伴 water ski （由快艇牵引水橇）滑水 buoy n. 浮标 dismay n. 沮丧 tremendous adj. 巨大的 petrol n. 汽油 drift v. 漂动，漂流 gently adv. 缓慢地，轻轻地 参考译文 当那人试图让快艇转弯时，方向盘脱手了。他绝望地向他的伙伴挥手，他的伙伴在过去的15分钟里一直在滑水。他们两个还没来得及意识到究竟发生了什么事情，就被猛地抛入了海里。快艇撞上了一个浮标，但它仍在水面上快速行驶着。两个人刚开始向岸边游去，就突然惊愕地发现快艇正在转着圈行驶，它现在正以惊人的速度直冲他们驶来。不到1分钟的工夫，它从离他们只有几英尺远的地方呼啸着驶了过去。快艇过去之后，他们以最快的速度向前游去，因为他们知道快艇马上就要转回来。他们刚刚来得及游出危险区，快艇就又转完了一圈。然而这一次它的速度慢多了。汽油几乎已经用光。没过多久，噪音便彻底消失，快艇开始在水面上慢悠悠地漂流。 Lesson 87 A perfect alibi 极好的不在犯罪现场的证据 First listen and then answer the question. 听录音，然后回答以下问题。 What was wrong with the man's story? 'At the time the murder was committed, I was travelling on the 8 o'clock train to London,' said the man. 'Do you always catch such an early train?' asked the inspector. 'Of course I do,' answered the man. 'I must be at work at 10 o'clock. My employer will confirm that I was there on time.' 'Would a later train get you to work on time?' asked the inspector. 'I suppose it would, but I never catch a later train.' 'At what time did you arrive at the station?' 'At ten to eight. I bought a paper and waited for the train.' 'And you didn't notice anything unusual?' 'Of course not.' 'I suggest,' said the inspector, 'that you are not telling the truth. I suggest that you did not catch the 8 o'clock train, but that you caught the 8.25 which would still get you to work on time. You see, on the morning of the murder, the 8 o'clock train did not run at all. It broke down at Ferngreen station and was taken off the line.' New words and expressions 生词和短语 alibi n. 不在犯罪现场 commit v. 犯（罪、错） inspector n. 探长 employer n. 雇主 confirm v. 确认，证实 suggest v. 提醒 truth n. 真相 参考译文 “在凶杀发生的时候，我正坐在8点钟开往伦敦的火车上。”那人说。 “您总是赶这样早的火车？”探长问。 “当然是的，”那人回答。“我必须在10点钟上班，我的雇主会证明我是按时到了那儿的。” “晚一点儿的车也能送您按时上班吗？” “我认为可以，但我从来不乘晚一点儿的车。” “您几点钟到的火车站？” “7点50分。我买了张报纸，等着车来。” “您没有注意到有什么异常情况发生吗？” “当然没有。” “我提醒您，”探长说，“您讲的不是实话。您乘的不是8点钟的火车，而是8点25分的，这次车同样能使您按时上班。您看，在凶杀发生的那天早晨，8点钟的那次车根本没有发。它在芬格林车站出了故障而被取消了。” Lesson 88 Trapped in a mine 困在矿井里 First listen and then answer the question. 听录音，然后回答以下问题。 Why is the rescue taking so long? Six men have been trapped in a mine for seventeen hours. If they are not brought to the surface soon they may lose their lives. However, rescue operations are proving difficult. If explosives are used, vibrations will cause the roof of the mine to collapse. Rescue workers are therefore drilling a hole on the north side of the mine. They intend to bring the men up in a special capsule. If there had not been a hard layer of rock beneath the soil, they would have completed the job in a few hours. As it is, they have been drilling for sixteen hours and they still have a long way to go. Meanwhile, a microphone, which was lowered into the mine two hours ago, has enabled the men to keep in touch with their closest relatives. Though they are running out of food and drink, the men are cheerful and confident that they will get out soon. They have been told that rescue operations are progressing smoothly. If they knew how difficult it was to drill through the hard rock, they would lose heart. New words and expressions 生词和短语 trap v. 陷入，使陷于困境 surface n. 地面，表面 explosive n. 炸药 vibration n. 震动 collapse v. 坍塌 drill v. 钻孔 capsule n. 容器 layer n. 层 beneath prep. 在......之下 lower v. 放下，降低 progress v. 进展，进行 smoothly adv. 顺利地 参考译文 6个人被困在矿井里已有17个小时了。如果不把他们尽快救到地面上来，他们就有可能丧生。然而，事实证明营救工作非常困难。如果用炸药爆破，震动会引起矿顶塌落。因此，营救人员在矿井的北侧钻了一个洞。他们准备用一种特制的容器把这6个人救上来。如果不是因为土壤下面有一层坚硬的岩石，他们的营救工作仅用几个小时就可以完成了。实际情况是，他们已连续钻了16个小时了，但离钻透还早着呢。与此同时，两个小时以前放下井去的一只麦克风使井下的人可以与其亲属保持联系。虽然他们的食物和饮料都快消耗尽了，但这些人的心情很好，坚信他们很快就会出去。他们一直被告知营救工作进行得非常顺利。如果他们知道了钻透那坚硬的岩石有多么困难，他们会丧失信心的。 Lesson 89 A slip of the tongue 口误 First listen and then answer the question. 听录音，然后回答以下问题。 Who made the only funny joke that evening and why? People will do anything to see a free show -- even if it is a bad one. When the news got round that a comedy show would be presented at our local cinema by the P. and U. Bird Seed Company, we all rushed to see it. We had to queue for hours to get in and there must have been several hundred people present just before the show began. Unfortunately, the show was one of the dullest we have ever seen. Those who failed to get in need not have felt disappointed, as many of the artistes who should have appeared did not come. The only funny things we heard that evening came from the advertiser at the beginning of the programme. He was obviously very nervous and for some minutes stood awkwardly before the microphone. As soon as he opened his mouth, everyone burst out laughing. We all know what the poor man should have said, but what he actually said was: 'This is the Poo and Ee Seed Bird Company. Good ladies, evening and gentlemen!" New words and expressions 生词和短语 slip n. 小错误 comedy n. 喜剧 present v. 演出；adj. 出席，到场的 queue v. 排队 dull adj. 枯燥，无味 artiste n. 艺人 advertiser n. 报幕员 参考译文 人们总要想尽办法看不花钱的演出——哪怕是拙劣的演出。当“皮尤”鸟食公司将在我们当地影院演出喜剧节目的消息传开后，我们都赶紧跑去观看。我们不得不排了好几个小时才进得场去。在演出开始前场内肯定已有好几百人了。不幸的是，这次演出是我们看过的最乏味的演出了。那些没能进到场内的人没有必要感到失望，因为很多应该出场的专业演员都没有来。那天晚上唯一有趣的事情是节目开始时那个报幕员的开场白。他显然非常紧张，局促不安地在麦克风前站了好几分钟。但他刚一开口说话，人们便哄堂大笑起来。我们都明白那个可怜的人应该说些什么，而他实际说的却是：“这是‘浦伊’鸟食公司，好女士们，晚上和先生们！” Lesson 90 What's for supper? 晚餐吃什么？ First listen and then answer the question. 听录音，然后回答以下问题。 What kind of fish are they? Fish and chips has always been a favourite dish in Britain, but as the oceans have been overfished, fish has become more and more expensive. So it comes as a surprise to learn that giant fish are terrifying the divers on North Sea oil rigs. Oil rigs have to be repaired frequently and divers, who often have to work in darkness a hundred feet under water, have been frightened out of their wits by giant fish bumping into them as they work. Now they have had special cages made to protect them from these monsters. The fish are not sharks or killer whales, but favourite eating varieties like cod and skate which grow to unnatural sizes, sometimes as much as twelve feet in length. Three factors have caused these fish to grow so large: the warm water round the hot oil pipes under the sea; the plentiful supply of food thrown overboard by the crews on the rigs; the total absence of fishing boats around the oil rigs. As a result, the fish just eat and eat and grow and grow in the lovely warm water. Who eats who? New words and expressions 生词和短语 chip n. 油煎土豆片 overfish v. 过度捕捞 giant adj. 巨大的 terrify v. 吓，使恐怖 diver n. 潜小员 oil rig 石油钻塔 wit n. （复数）理智，头脑 cage n. 笼 shark n. 鲨鱼 whale n. 鲸 variety n. 品种 cod n. 鳕 skate n. 鳐 factor n. 因素 crew n. 全体工作人员 参考译文 油煎鱼加炸土豆片一直是英国人喜爱的一道菜，但是随着海洋里的滥捕滥捞，鱼已经变得越来越昂贵。因此，听说北海石油钻井平台上的潜水员受到巨型鱼类的恐吓，确实很让人吃惊。钻井平台需要经常修理，潜水员常常要在水面100英尺以下摸黑工作，他们曾在工作时被撞到他们身上的大鱼吓得惊惶失措。现在他们有了特制的笼子，用来保护他们免受大鱼的侵袭。这些鱼并不是鲨鱼或逆戟鲸，而是深受人们喜爱的食用鱼品种，如鳕鱼和鳐鱼，只不过它们长得出奇地大，有时长达12英尺。这些鱼能长得这么大是由3个因素造成的：海底热的输油管道附近的温暖的海水；钻井平台工作人员抛到海里充足的食物；钻井平台周围根本没有捕鱼船只。结果是，这些鱼就在可爱的温暖的水流中吃呀吃，长呀长。究竟谁吃谁呢？ Lesson 91 Three men in a basket 三人同篮 First listen and then answer the question. 听录音，然后回答以下问题。 Where was the station's Commanding Officer? A pilot noticed a balloon which seemed to be making for a Royal Air Force Station nearby. He informed the station at once, but no one there was able to explain the mystery. The officer in the control tower was very angry when he heard the news, because balloons can be a great danger to aircraft. He said that someone might be spying on the station and the pilot was ordered to keep track of the strange object. The pilot managed to circle the balloon for some time. He could make out three men in a basket under it and one of them was holding a pair of binoculars. When the balloon was over the station, the pilot saw one of the men taking photographs. Soon afterwards, the balloon began to descend and it landed near an airfield. The police were called in, but they could not arrest anyone, for the basket contained two Members of Parliament and the Commanding Officer of the station! As the Commanding Officer explained later, one half of the station did not know what the other half was doing! New words and expressions 生词和短语 balloon n. 气球 royal adj. 皇家 spy v. 侦察 track n. 轨迹，踪迹 binoculars n. 望远镱 参考译文 一个飞行员发现了一只气球，它像是正飞往附近的一个皇家空军基地。他马上把情况报告了该基地，但那里的人没有一个能解释这到底是怎么回事。控制塔上的官员得知这一消息后，非常气愤，因为气球有可能给飞机造成极大的危险。他说可能有人正对基地进行侦察，因此命令那个飞行员跟踪那个奇怪的飞行物。飞行员设法绕着气球飞了一阵。他看清了气球下面有3个人呆在一只筐里，其中一个举着望远镜。当气球飞临基地上空时，飞行员看见有一个人在拍照。不久，气球开始降落，在一个停机坪附近着了陆。警察被召来了，但他们却不能逮捕任何人，因为筐里是两名国会议员和一名基地的指挥官！正如指挥官后来解释的那样，基地的这半边不知道那半边正在干什么！ Lesson 92 Asking for trouble 自找麻烦 First listen and then answer the question. 听录音，然后回答以下问题。 Why did the policeman ask the writer to come to the police station? It must have been about two in the morning when I returned home. I tried to wake up my wife by ringing the doorbell, but she was fast asleep, so I got a ladder from the shed in the garden, put it against the wall, and began climbing towards the bedroom window. I was almost there when a sarcastic voice below said, 'I don't think the windows need cleaning at this time of the night.' I looked down and nearly fell off the ladder when I saw a policeman. I immediately regretted answering in the way I did, but I said, 'I enjoy cleaning windows at night.' 'So do I,' answered the policeman in the same tone. 'Excuse my interrupting you. I hate to interrupt a man when he's busy working, but would you mind coming with me to the station?' 'Well, I'd prefer to stay here,' I said. 'You see. I've forgotten my key.' 'Your what?' he called. 'My key,' I shouted. Fortunately, the shouting woke up my wife who opened the window just as the policeman had started to climb towards me. New words and expressions 生词和短语 fast adv. 熟（睡） ladder n. 梯子 shed n. 棚子 sarcastic adj. 讽刺的，讥笑的 tone n. 语气，腔调 参考译文 我回到家时，肯定已是凌晨两点左右了。我按响了门铃，试图唤醒我的妻子，但她睡得很熟。于是，我从花园的小棚里搬来了一个梯子，把它靠在墙边，开始向卧室的窗口爬去。快要爬到窗口时，下面一个人用讽刺的口吻说：“我看不必在夜里这个时候擦窗子吧。”我向下面看去。当我看清是一个警察时，差一点儿从梯子上掉下去。我回答了他的话，但马上又后悔不该那样说，我是这样说的：“我喜欢在夜里擦窗子。” “我也是的，”警察用同样的声调回答，“请原谅我打断了您。当一个人在忙着干活时，我是不愿意去打断他的，但请您跟我到警察局去一趟好吗？” “可我更愿意呆在这儿，”我说，“您瞧，我忘带钥匙了。” “什么？”他大声问。 “钥匙！”我喊道。 幸运得很，这喊声惊醒了我的妻子。就在警察开始向我爬上来时，她打开了窗子。 Lesson 93 A noble gift 崇高的礼物 First listen and then answer the question. 听录音，然后回答以下问题。 Where was the Statue of Liberty made? One of the most famous monuments in the world, the Statue of Liberty, was presented to the United States of America in the nineteenth century by the people of France. The great statue, which was designed by the sculptor Auguste Bartholdi, took ten years to complete. The actual figure was made of copper supported by a metal framework which had been especially constructed by Eiffel. Before it could be transported to the United States, a site had to be found for it and a pedestal had to be built. The site chosen was an island at the entrance of New York Harbour. By 1884, a statue which was 151 feet tall had been erected in Paris. The following year, it was taken to pieces and sent to America. By the end of October 1886, the statue had been put together again and it was officially presented to the American people by Bartholdi. Ever since then, the great monument has been a symbol of liberty for the millions of people who have passed through New York Harbour to make their homes in America. New words and expressions 生词和短语 noble adj. 高尚的，壮丽的 monument n. 纪念碑 statue n. 雕像 liberty n. 自由 present v. 赠送 sculptor n. 雕刻家 actual adj. 实际的，真实的 copper n. 铜 support v. 支持，支撑 framework n. 构架，框架 transport v. 运送 site n. 场地 pedestal n. 底座 参考译文 世界上最著名的纪念碑之一的自由女神雕像是在19世纪时由法国人民赠送给美国的。这座由雕像家奥古斯特.巴索尔地设计的巨大雕像是用10年时间雕像刻成的。这座雕像的主体是用铜制成的，由艾菲尔特制的金属框架支撑着。在雕像被运往美国之前，必须为它选好一块场地，同时必须建造一个基座。场地选在了纽约港入口处的一个鸟上。到1884年，一座高度达151英尺的雕像在巴黎竖立起来了。第二年，它被拆成若干小块，运到美国。到1886年10月底，这座雕像被重新组装起来，由巴索尔地正式赠送给美国人民。从那时起，这座伟大的纪念碑对通过纽约港进入美国定居的千百万人来说就一直是自由的象征。 Lesson 94 Future champions 未来的冠军 First listen and then answer the question. 听录音，然后回答以下问题。 What kind of race do the children compete in? Experiments have proved that children can be instructed in swimming at a very early age. At a special swimming pool in Los Angeles, children become expert at holding their breath under water even before they can walk. Babies of two months old do not appear to be reluctant to enter the water. It is not long before they are so accustomed to swimming that they can pick up weights from the floor of the pool. A game that is very popular with these young swimmers is the underwater tricycle race. Tricycles are lined up on the floor of the pool seven feet under water. The children compete against each other to reach the other end of the pool. Many pedal their tricycles, but most of them prefer to push or drag them. Some children can cover the whole length of the pool without coming up for breath even once. Whether they will ever become future Olympic champions, only time will tell. Meanwhile, they should encourage those among us who cannot swim five yards before they are gasping for air. New words and expressions 生词和短语 instruct v. 指导，传授 Los Angeles 洛杉矶 reluctant adj. 勉强的，不愿意的 weight n. 重物 underwater adj. 水下的 tricycle n. 三轮车 compete v. 比赛，对抗 yard n. 码 gasp v. 喘气 参考译文 实验证明，儿童在很小的时候就可以开始学习游泳。在洛杉矶的一个特设的游泳池里，孩子们甚至在还没有学会走路时就已经能熟练地在水下屏住呼吸了。两个月的婴儿并未显得不愿意入水。他们很快便适应了游泳，以致能捡起池底的物品。这些幼小的游泳运动员非常喜爱的一种游戏是水下三轮车比赛。三轮车并排放在7英尺深的游泳池底上。孩子们比赛看谁先到达游泳池的另一端。很多孩子用脚蹬车，但多数孩子更愿意推或是拉着三轮车。有些孩子能够跑完游泳池的全长而不用露出水面换气。他们将来是否能成为奥林匹克的冠军，这只能由时间来作出回答。与此同时，他们对我们中的那些游不了5码就已喘不过气来的人应该是种鼓舞。 Lesson 95 A fantasy 纯属虚构 First listen and then answer the question. 听录音，然后回答以下问题。 Why was the Ambassador particularly lucky? When the Ambassador or Escalopia returned home for lunch, his wife got a shock. He looked pale and his clothes were in a frightful state. 'What has happened?' she asked. 'How did your clothes get into such a mess?' 'A fire extinguisher, my dear,' answered the Ambassador drily. 'University students set the Embassy on fire this morning.' 'Good heavens!' exclaimed his wife. 'And where were you at the time?' 'I was in my office as usual,' answered the Ambassador. 'The fire broke out in the basement. I went down immediately, of course, and that fool, Horst, aimed a fire extinguisher at me. He thought I was on fire. I must definitely get that fellow posted.' The Ambassador's wife went on asking questions, when she suddenly noticed a big hole in her husband's hat. 'And how can you explain that?' she asked. 'Oh, that,' said the Ambassador. 'Someone fired a shot through my office window. Accurate, don't you think? Fortunately, I wasn't wearing it at the time. If I had been, I would not have been able to get home for lunch.' New words and expressions 生词和短语 fantasy n. 幻想故事 ambassador n. 大使 Escalopia n. 艾斯卡罗比亚（虚构的国名） frightful adj. 可怕的，令人吃惊的 fire extinguisher 灭火器 drily adv. 冷淡地，枯燥无味地 embassy n. 大使馆 heaven n. 天，天堂 basement n. 地下室 definitely adv. 肯定地 post v. 派任 shot n. 子弹 参考译文 当艾斯卡罗比亚国的大使回到家吃午饭时，把他的夫人吓了一跳。他面色苍白，衣服也搞得不成样子。 “发生了什么事？”她问，“你的衣服怎么搞得一塌糊涂？” “灭火器弄的，亲爱的，”大使冷冷地回答，“今天上午大学生们放火点着了大使馆。” “天啊！”他的夫人惊叫，“那你当时在什么地方？” “我和往常一样，在办公室里，”大使回答说。“地下室突然着火，我当然马上下去了。但那个傻瓜霍斯特把灭火器对准了我。他认为是我着火了。我一定要把那个家伙打发走。” 大使夫人继续提出问题，她突然又发现丈夫的帽子上有个洞。 “那么你对那又作何解释呢？”她问。 “那个嘛，”大使说，“有人向我办公室窗户开了一枪。真够准的，是不是？幸亏我当时没戴帽子。如果真戴着它，我现在就不能回家来吃午饭了。” Lesson 96 The dead return 亡灵返乡 First listen and then answer the question. 听录音，然后回答以下问题。 What happens to the lanterns at the end of the festival? A Festival for the Dead is held once a year in Japan. This festival is a cheerful occasion, for on this day, the dead are said to return to their homes and they are welcomed by the living. As they are expected to be hungry after their long journey, food is laid out for them. Specially-made lanterns are hung outside each house to help the dead to find their way. All night long, people dance and sing. In the early morning, the food that had been laid out for the dead is thrown into a river or into the sea as it is considered unlucky for anyone living to eat it. In towns that are near the sea, the tiny lanterns which had been hung in the streets the night before, are placed into the water when the festival is over. Thousands of lanterns slowly drift out to sea guiding the dead on their return journey to the other world. This is a moving spectacle, for crowds of people stand on the shore watching the lanterns drifting away until they can be seen no more. New words and expressions 生词和短语 festival n. 节日 lantern n. 灯笼 spectacle n. 景象，壮观，场面 参考译文 日本每年过一次“亡灵节”。这个节日是个欢乐的日子，因为在这一天，据说死去的人要回到他们的家里来，活着的人则对他们表示欢迎。因为预料到他们在经过长途旅行之后会感到饥饿，所以为他们摆放好了食品。特制的灯笼挂在各家的门外，为的是帮助亡灵看清道路。整个夜晚人们载歌载舞。一大早，人们便把为死者摆放的食品扔进河中或海里，因为人们认为活着的人吃了这些东西是不吉利的。在靠海的城镇中，头天夜里挂在大街小巷的小灯笼在节后就放在了水里。成千上万只灯笼慢慢漂向大海，指引着亡灵返回另一个世界。这是一个感人的场面，人们成群地伫立在海岸上，注视着灯笼远去，直到再也看不见为止。 新生代俱乐部 www.popday.net 倾情奉献 Lesson 1 A Puma at large 逃遁的美洲狮 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Where must the puma have come from? Pumas are large, cat-like animals which are found in America. When reports came into London Zoo that a wild puma had been spotted forty-five miles south of London, they were not taken seriously. However, as the evidence began to accumulate, experts from the Zoo felt obliged to investigate, for the descriptions given by people who claimed to have seen the puma were extraordinarily similar. The hunt for the puma began in a small village where a woman picking blackberries saw 'a large cat' only five yards away from her. It immediately ran away when she saw it, and experts confirmed that a puma will not attack a human being unless it is cornered. The search proved difficult, for the puma was often observed at one place in the morning and at another place twenty miles away in the evening. Wherever it went, it left behind it a trail of dead deer and small animals like rabbits. Paw prints were seen in a number of places and puma fur was found clinging to bushes. Several people complained of "cat-like noises' at night and a businessman on a fishing trip saw the puma up a tree. The experts were now fully convinced that the animal was a puma, but where had it come from? As no pumas had been reported missing from any zoo in the country, this one must have been in the possession of a private collector and somehow managed to escape. The hunt went on for several weeks, but the puma was not caught. It is disturbing to think that a dangerous wild animal is still at large in the quiet countryside. New words and expressions 生词和短语 puma n. 美洲狮 spot v. 看出，发现 evidence n. 证据 accumulate v. 积累，积聚 oblige v. 使……感到必须 hunt n. 追猎；寻找 blackberry n. 黑莓 human being 人类 corner v. 使走投无路，使陷入困境 trail n. 一串，一系列 print n. 印痕 cling v. 粘 convince v. 使……信服 somehow adv. 不知怎么搞地，不知什么原因 disturb v. 令人不安 参考译文 美洲狮是一种体形似猫的大动物，产于美洲。当伦敦动物园接到报告说，在伦敦以南45英里处发现一只美洲狮时，这些报告并没有受到重视。可是，随着证据越来越多，动物园的专家们感到有必要进行一番调查，因为凡是声称见到过美洲狮的人们所描述的情况竟是出奇地相似。 搜寻美洲狮的工作是从一座小村庄开始的。那里的一位妇女在采摘黑莓时的看见“一只大猫”，离她仅5码远，她刚看见它，它就立刻逃走了。专家证实，美洲狮非被逼得走投无路，是决不会伤人的。事实上搜寻工作很困难，因为常常是早晨在甲地发现那只美洲狮，晚上却在20英里外的乙地发现它的踪迹。无论它走哪儿，一路上总会留下一串死鹿及死兔子之类的小动物，在许多地方看见爪印，灌木丛中发现了粘在上面的美洲狮毛。有人抱怨说夜里听见“像猫一样的叫声”；一位商人去钓鱼，看见那只美洲狮在树上。专家们如今已经完全肯定那只动物就是美洲狮，但它是从哪儿来的呢？由于全国动物园没有一家报告丢了美洲狮，因此那只美洲狮一定是某位私人收藏豢养的，不知怎么设法逃出来了。搜寻工作进行了好几个星期，但始终未能逮住那只美洲狮。想到在宁静的乡村里有一头危险的野兽继续逍遥流窜，真令人担心。 Lesson 2 Thirteen equals one 十三等于一 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Was the vicar pleased that the clock was striking? Why? Our vicar is always raising money for one cause or another, but he has never managed to get enough money to have the church clock repaired. The big clock which used to strike the hours day and night was damaged many years ago and has been silent ever since. One night, however, our vicar work up with a start: the clock was striking the hours! Looking at his watch, he saw that it was one o'clock, but the bell struck thirteen times before it stopped. Armed with a torch, the vicar went up into the clock tower to see what was going on. In the torchlight, he caught sight of a figure whom he immediately recognized as Bill Wilkins, our local grocer. 'Whatever are you doing up here Bill?' asked the vicar in surprise. 'I'm trying to repair the bell,' answered Bill. 'I've been coming up here night after night for weeks now. You see, I was hoping to give you a surprise.' 'You certainly did give me a surprise!' said the vicar. 'You've probably woken up everyone in the village as well. Still, I'm glad the bell is working again.' That's the trouble, vicar,' answered Bill. 'It's working all right, but I'm afraid that at one o'clock it will strike thirteen times and there's nothing I can do about it." We'll get used to that, Bill,' said the vicar. "Thirteen is not as good as one, but it's better than nothing. Now let's go downstairs and have a cup of tea.' New words and expressions 生词和短语 equal v. 等于 vicar n. 牧师 raise v. 募集，筹（款） torchlight n. 电筒光 参考译文 我们教区的牧师总是为各种各样的事筹集资金。但始终未能筹足资金把教堂的钟修好。教堂的钟很大，以前不分昼夜打点报时，但很多年前遭到毁坏，从此便无声无息了。 一天夜里，我们的牧师突然被惊醒了，大钟又在“打点”报时了！他一看表，才1点钟，可是那钟一边敲了13下才停。牧师拿着一支电筒走上钟楼想去看看究竟发生了什么事情。借着电筒光。他看见一个人，马上认出那是本地杂货店主经比尔.威尔金斯。 “你究竟在这上面干什么，比尔？”牧师惊讶地问。 “我想把这口钟修好，”比尔回答说。“好几个星期了，我天天夜里到钟楼上来。嗯，我是想让你大吃一惊。” “你确实使我大吃了一惊！”牧师说，“也许同时你把村里所有的人都吵醒了。不过，钟又能报时了，我还是很高兴的。” “问题就在这里，牧师，”比尔回答说。“不错，钟能报时了，但是，恐怕每到1点钟，它总要敲13下，对此我已无能为力了。” “大家慢慢就习惯了，比尔，”牧师说。“13下是不如1下好，但总比1下也不敲强。来，咱们下楼去喝杯茶吧。” Lesson 3 An unknown goddess 无名女神 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 How did the archaeologists know that the statue was a goddess? Some time ago, and interesting discovery was made by archaeologists on the Aegean island of Kea. An American team explored a temple which stands in an ancient city on the promontory of Ayia Irini. The city at one time must have been prosperous, for it enjoyed a high level of civilization. Houses -- often three storeys high -- were built of stone. They had large rooms with beautifully decorated walls. The city was equipped with a drainage system, for a great many clay pipes were found beneath the narrow streets. The temple which the archaeologists explored was used as a place of worship from the fifteenth century B.C. until Roman times. In the most sacred room of temple, clay fragments of fifteen statues were found. Each of these represented a goddess and had, at one time, been painted. The body of one statue was found among remains dating from the fifteenth century B.C. It's missing head happened to be among remains of the fifth century B.C. This head must have been found in Classical times and carefully preserved. It was very old and precious even then. When the archaeologists reconstructed the fragments, they were amazed to find that the goddess turned out to be a very modern-looking woman. She stood three feet high and her hands rested on her hips. She was wearing a full-length skirt which swept the ground. Despite her great age, she was very graceful indeed, but, so far, the archaeologists have been unable to discover her identity. New words and expressions 生词和短语 goddess(tile) n. 女神 archaeologist n. 考古学家 Aegean adj. 爱玲海的 explore v. 考察，勘探 promontory n. 海角 prosperous adj. （经济上）繁荣的，昌盛的 civilization n. 文明 storey n. 楼层 drainage n. 排水 worship n. 祟拜 sacred adj. 宗教的，神圣的 fragment n. 碎片 remains n. 遗物，遗迹，废墟 classical adj. （希腊和罗马）古化的 reconstruct v. 修复 rest v. 倚放，放置 hip n. 屁股，臀部 full-length adj. （裙衣）拖地长的 graceful adj. 优雅的 identity n. 身份 参考译文 不久之前，在爱琴海的基亚岛上，考古工作者有一项有趣的发现。一个美国考古队在阿伊亚.依里尼海角的一座古城里考察了一座庙宇。这座古城肯定一度很繁荣，因为它曾享有高度的文明，房子一般有3层楼高，用石块修建。里面房间很大，墙壁装饰华丽。城里甚至还敷设了排水系统，因为在狭窄的街道底下发现了许许多多陶土制作的排水管道。 考古工作者考察的这座庙宇从公元前15世纪直到罗马时代一直是祭祀祈祷的场所。在庙中最神圣的一间殿堂里发现了15尊陶雕像的碎片。每一尊雕像代表一位女神，而且一度上过色。其中有一尊雕像，她的躯体是在公元前15世纪的历史文物中发现的，而她那身异处的脑袋却碰巧是在公元前5世纪的文物中找到的。她的脑袋一定是在古希腊罗马时代就为人所发现，并受到精心的保护。却使在当时，它也属历史悠久的珍奇之物。考古工作者把这些碎片重新拼装起来后，惊奇地发现那位女神原来是一位相貌十分摩登的女郎。她身高3英尺，双手叉腰。身穿一条拖地长裙，尽管上了年纪，但体态确实优美。不过，考古工作者至今未能确定这位女神的身份。 Lesson 4 The double life of Alfred Bloggs 阿尔弗雷德.布洛格斯的双重生活 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Why did Alf want a white-collar job? These days, people who do manual work often receive far more money than people who work in offices. People who work in offices are frequently referred to as "white-collar workers' for the simple reason that they usually wear a collar and tie to go to work. Such is human nature, that a great many people are often willing to sacrifice higher pay for the privilege of becoming white-collar workers. This can give rise to curious situations, as it did in the case of Alfred Bloggs who worked as a dustman for the Ellesmere Corporation. When he got married, Alf was too embarrassed to say anything to his wife about his job. He simply told her that he worked for the Corporation. Every morning, he left home dressed in a smart black suit. He then changed into overalls and spent the next eight hours as a dustman. Before returning home at night. He took a shower and changed back into his suit. Alf did this for over two years and his fellow dustmen kept his secret Alf's wife has never discovered that she married a dustman and she never will, for Alf has just found another job. He will soon be working in an office. He will be earning only half as much as he used to, but he feels that his rise in status is well worth the loss of money. From now on, he will wear a suit all day and others will call him 'Mr. Bloggs', not 'Alf'. New words and expressions 生词和短语 manual adj. 体力的 collar n. 衣领 sacrifice v. 牺牲，献出 privilege n. 好处 dustman n. 清洁工 corporation n. 公司 overalls n. 工作服 shower n. 淋浴 secret n. 秘密 status n. 地位 参考译文 如今，从事体力劳动的人的收入一般要比坐办公室的人高出许多。坐办公室的之所以常常被称作“白领工人”，就是因为他们通常是穿着硬领白衬衫，系着领带去上班。许多人常常情愿放弃较高的薪水以换取做白领工人的殊荣，此乃人之常情。而这常常会引起种种奇怪的现象，在埃尔斯米尔公司当清洁工的艾尔弗雷德.布洛斯就是一个例子。 艾尔弗结婚时，感到非常难为情，而没有将自己的职业告诉妻子。他只说在埃尔斯米尔公司上班。每天早晨，他穿上一身漂亮的黑色西装离家上班，然后换上工作服，当8个小时清洁工。晚上回家前，他洗个淋浴，重新换上那身黑色西服。两年多以来，艾尔弗一直这样，他的同事也为他保守秘密。艾尔弗的妻子一直不知道她嫁给了一个清洁工，而且她永远也不会知道了，因为艾尔弗已找到薪职，不久就要坐办公室里工作了。他将来挣的钱只有他现在的一半。不过他觉得，地位升高了，损失点儿钱也值得。从此，艾尔弗可以一天到晚穿西服了。别人将称呼他为“布洛格斯先生”，而不再叫他“艾尔弗”了。 Lesson 5 The facts 确切数字 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What was the consequence of the editor's insistence on facts and statistics? Editors of newspapers and magazines often go to extremes to provide their reader with unimportant facts and statistics. Last year a journalist had been instructed by a well-known magazine to write an article on the president's palace in a new African republic. When the article arrived, the editor read the first sentence and then refuse to publish it. The article began: 'Hundreds of steps lead to the high wall which surrounds the president's palace'. The editor at once sent the journalist a fax instructing him find out the exact number of steps and the height of the wall. The journalist immediately set out to obtain these important facts, but the took a long time to send them Meanwhile, the editor was getting impatient, for the magazine would soon go to press. He sent the journalist two more faxes, but received no reply. He sent yet another fax informing the journalist that if he did not reply soon he would be fired. When the journalist again failed to reply, the editor reluctantly published the article as it had originally been written. A week later, the editor at last received a fax from the journalist. Not only had the poor man been arrested, but he had been sent to prison as well. However, he had at last been allowed to send a fax in which he informed the editor that the he had been arrested while counting the 1,084 steps leading to the fifteen-foot wall which surrounded the president's palace. New words and expressions 生词和短语 editor n. 编辑 extreme n. 极端 statistics n. 统计数字 journalist n. 新闻记者 president n. 总统 palace n. 王宫；宏伟的住宅 publish v. 出版 fax n. 传真 impatient adj. 不耐烦的 fire v. 解雇 originally adv. 起初，原先，从前 参考译文 报刊杂志的编辑常常为了向读者提供成立一些关紧要的事实和统计数字而走向极端。去年，一位记者受一家有名的杂志的委托写一篇关于非洲某个新成立共和国总统府的文章。稿子寄来后，编辑看第一句话就拒绝予以发表。文章的开头是这样的：“几百级台阶通向环绕总统的高墙。”编辑立即给那位记者发去传真，要求他核实一下台阶的确切数字和围墙的高度。 记者立即出发去核实这些重要的事实，但过了好长时间不见他把数字寄来，在此期间，编辑等得不耐烦了，因为杂志马上要付印。他给记者先后发去两份传真，但对方毫无反应。于是他又发了一份传真，通知那位记者说，若再不迅速答复，将被解雇。但记者还是没有回复。编辑无奈，勉强按原样发稿了。一周之后，编辑终于接到记者的传真。那个可怜的记者不仅被捕了，而且还被送进了监狱。不过，他终于获准发回了一份传真。在传真中他告诉编辑，就在他数通向15英尺高的总统府围墙的1，084级台阶时，被抓了起来。 Lesson 6 Smash-and-grab 砸橱窗抢劫 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 How did Mr. Taylor try to stop the thieves? The expensive shops in a famous near Piccadilly were just "opening. At this time of the morning, the arcade was almost empty. Mr. Taylor, the owner of a jewellery shop was admiring a new display. Two of his assistants had been working busily since eight o'clock and had only just finished. Diamond necklaces and rings had been beautifully arranged on a background of black velvet. After gazing at the display for several minutes, Mr. Taylor went back into his shop. The silence was suddenly broken when a large car, with its headlights on and its home blaring, roared down the arcade. It came to a stop outside the jeweller's. One man stayed at the wheel while two others with black stocking over their faces jumped out and smashed the window of the shop with iron bars. While this was going on, Mr. Taylor was upstairs. He and his staff began throwing furniture out of the window. Chairs and tables went flying into the arcade. One of the thieves was struck by a heavy statue, but he was too busy helping himself to diamonds to notice any pain. The raid was all over in three minutes, for the men scrambled back into the car and it moved off at a fantastic speed. Just as it was leaving, Mr. Taylor rushed out and ran after it throwing ashtrays and vases, but it was impossible to stop the thieves. They had got away with thousands of pounds worth of diamonds. New words and expressions 生词和短语 smash-and-grab n. 砸橱窗抢劫 arcade n. 有拱廊的街道（两旁常设商店） Piccadilly n. 皮卡迪利大街 jewllery n. 珠宝（总称） necklace n. 项链 ring n. 戒指 background n. 背景 velvet n. 天鹅绒，丝绒 headlight n. （汽车等）前灯 blare v. 发嘟嗜声，吼叫 staff n. 全体工作人员 raid n. 偷袭 scramble n. 偷袭 scramble v. 爬行 fantastic adj. 非常大的 ashtray n. 烟灰缸 参考译文 皮卡迪利大街附近的一条著名拱廊街道上，几家高档商店刚刚开始营业。在早晨的这个时候，拱廊街上几乎空无一人。珠宝店主泰勒先生正在欣赏新布置的橱窗。他手下两名店员从早上8点就开始忙碌，这时刚刚布置完毕。钻石项链、戒指漂亮地陈列在黑色丝绒上面。泰勒先生站在橱窗外凝神欣赏了几分钟就回到了店里。 宁静突然被打破，一辆大轿车亮着前灯，响着喇叭，呼啸着冲进了拱廊街，在珠宝店门口停了下来。一人留在驾驶座上，另外两个用黑色长筒丝袜蒙面的人跳下车来。他们用铁棒把商店橱窗的玻璃砸碎。这开始发生时，泰勒先生正在楼上。他与店员动手向窗外投掷家具，椅子，桌子飞落花流水在拱廊街上。一个窃贼被一尊很重的雕像击中，但由于他忙着抢钻石首饰，竟连疼痛都顾不上了。这场抢劫只持续了3分钟，因为窃贼争先恐后地爬上轿车，以惊人的速度开跑了。就在轿车离开的时候，泰勒先生从店里冲了出来，跟在车后追赶，一边还往车上扔烟灰缸、花瓶。但他已无法抓住那些窃贼了。他们已带着价值数千镑的首饰逃之夭夭了。 Lesson 7 Mutilated ladies 残钞鉴别组 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Why did Jane cook John's wallet? Has it ever happened to you? Have you ever put your trousers in the washing machine and then remembered there was a large bank note in your back pocket? When you rescued your trousers, did note in your back pocket? When you rescued your trousers, did you find the note was whiter than white? People who live in Britain needn't despair when they made mistakes like this (and a lot of people do)! Fortunately for them, the Bank of England has a team called Mutilated Ladies which deals with claims from people who fed their money to a machine or to their dog. Dogs, it seems, love to chew up money! A recent case concerns Jane Butlin whose fiancé, John, runs a successful furniture business. John had very good day and put his wallet containing$3,000 into the microwave oven for safekeeping. Then he and Jane went horse-riding. When they got home, Jane cooked their dinner in the microwave oven and without realizing it, cooked her fiancé's wallet as well. Imagine their dismay when they found a beautifully-cooked wallet and notes turned to ash! John went to see his bank manager who sent the remains of wallet and the money to the special department of the Bank of England in Newcastle: the Mutilate Ladies! They examined the remain and John got all his money back. 'So long as there's something to identify, we will give people their money back,' said a spokeswoman for the Bank. 'Last year, we paid $1.5m on 21,000 claims. Damaged bank notes. The Queen's head appears on English bank notes, and 'lady' refers to this. New words and expressions 生词和短语 mutilate v. 使残缺不全 chew v. 咀嚼 microwave n. 微波，微波炉 oven n. 炉灶 safekeeping n. 妥善保管 Newcastle n. 纽卡斯尔（英国港市） identify v. 鉴定，识别 spokeswoman n. 女发言人 参考译文 这种事情在你身上出现过吗？你有没有把裤子塞洗衣机，然后又想在裤子的后兜有一张大面值的纸币？当你把裤子抢救出来时，你有没有发现那张纸币已经变得比白纸还白？当英国人犯这种错误时，他们不必感到绝望（而许多国家的人都有这种绝望的感觉）。对英国人来说，值得庆幸的是英国银行有一个残钞鉴别组，负责理那些把钱塞进机器或塞给狗的人提出的索赔要求。看起来，狗很喜欢咀嚼钱币。 最近的一个案例与简.巴特林有关，她的未婚夫约翰拥有一家生意兴隆家具店。有一天约翰的生意很好，他把一只装有3,000 英镑的钱包放进微波炉内保存。然后，他和简一起去骑马。回家后，简用微波炉煮了晚饭，无意中之中把她未婚夫的钱包也一起煮了。可以想像他们发现一只煮得很好看的钱包，钞票已化成灰时的沮丧心情。约翰去找银行经理，经理把约翰的钱包和纸币的残留物送到英国银行在纽卡斯尔的一个专门部门——残钞鉴别组。他们鉴定了这些残留物。约翰拿回了他损失的全部数额。“只要有东西可供识别，我们会把钱还给人家的，”银行的一位女发言人说。“去年，我们对21，000 起索赔要求支付了150万英镑。” Lesson 8 A famous monastery 著名的修道院 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What are the St. Bernard dogs used for? The Great St. Bernard Pass connects Switzerland to Italy. At 2,473 metres, it is the highest mountain pass in Europe. The famous monastery of St. Bernard, witch was founded in eleventh century, lies about a mile away. For hundreds of years, St. Bernard dogs have saved the lives of travellers crossing the dangerous Pass. These friendly dogs, which were first brought from Asia, were used as watchdogs even in Roman times. Now that a tunnel ahs been built through the mountains, the Pass is less dangerous, but each year, the dogs are still sent out into the snow whenever a traveller is in difficulty. Despite the new tunnel, there are still a few people who rashly attempt to cross the Pass on foot. During the summer months, the monastery is very busy, for it is visited by thousands of people who cross the Pass in cars. As there are so many people about, the dogs have to be kept in a special enclosure. In winter, however, life at the monastery is quite different. The temperature drops to -- 30 o and very few people attempt to cross the Pass. The monks prefer winter to summer of they have more privacy. The dogs have greater freedom, too, for they are allowed to wander outside their enclosure. The only regular visitors to the monastery in winter are parties of skiers who go there at Christmas and Easter. These young people, who love the peace of mountains, always receive a warm welcome at St. Bernard's monastery. New words and expressions 生词和短语 monastery n. 寺院，修道院 St. Bernard 圣伯纳德 pass n. 关隘 watchdog n. 看门狗 rashly adj. 莽撞地，冒失地 enclosure n. 围场，圈地 monk n. 和尚 privacy n. 清静，隐居 skier n. 滑雪者 Easter n. 复活节 参考译文 圣伯纳德大山口连接着瑞士与意大利，海拔2,473O米，是欧洲最高的山口。11世纪建造的著名的圣伯纳德修道院位于离山口1英里远的地方。几百年来，圣伯纳德修道院驯养狗拯救了许多翻越这道山口的旅游者的生命。那些最先从亚洲引进的狗，待人友好，早在罗马时代就给人当看门狗了。如今由于山里开挖了隧道，翻越山口已不那么危险了。但每年还要派狗到雪山地里去帮助那些遇到困难的旅游者，尽管修通了隧道，但仍有一些人想冒险徒步跨越圣伯纳德山口。 夏天的几个月里，修道院十分忙碌，因为有成千上万的人驾车通过山口，顺道来修道院参观。由于来人太多，狗被关在专门的围栏里。然而到了冬天，修道院里的生活则是另一番景象。气温下降到零下30度，试图跨越山口的人寥寥无几。修道士们喜欢冬天，而不太喜欢夏天。因为在冬天，他们可以更多地过无人打扰的生活。狗也比较自由，被放出围栏，四处遛达。冬天常来修道院参观的只有一批批滑雪者。他们在圣诞节或复活节到那儿去。这些热爱高山清静环境的年轻人每年都受到圣伯纳德道院的热烈欢迎。 Lesson 9 Flying cats 飞猫 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 How do cats try to protect themselves when falling from great heights? Cats never fail to fascinate human beings. They can be friendly and affectionate towards humans, but they lead mysterious lives of their own as well. They never become submissive like dogs and horses. As a result, humans have learned to respect feline independence. Most cats remain suspicious of humans all their lives. One of the things that fascinates us most about cats is the popular belief that they have nine lives. Apparently, there is a good deal of truth in this idea. A cat's ability to survive falls is based on fact. Recently the New York Animal Medical Center made a study of 132 cats over a period of five months. All these cats had one experience in common: they had fallen off high buildings, yet only eight of them died from shock or injuries. Of course, New York is the ideal place for such an interesting study, because there is no shortage of tall buildings. There are plenty of high-rise windowsills to fall from! One cat, Sabrina, fell 32 storeys, yet only suffered from a broken tooth. 'Cats behave like well-trained paratroopers.' a doctor said. It seems that the further cats fall, the less they are likely to injure themselves. In a long drop, they reach speeds of 60 miles an hour and more. At high speeds, falling cats have time to relax. They stretch out their legs like flying squirrels. This increases their air-resistance and reduces the shock of impact when they hit the ground. New words and expressions 生词和短语 fascinate v. 迷住，吸引住 affectionate adj. 充满深情，柔情的 mysterious adj. 神秘的，难以理解的 submissive adj. 服从的，顺从的 feline adj. 猫的 independence n. 独立，独立性 high-rise adj. 高层的 windowsill n. 窗槛 paratrooper n. 伞兵 squirrel n. 松鼠 air-resistance n. 空气阻力 impact n. 冲击力 参考译文 猫总能引起人们的极大兴趣。它们可以对人友好，充满柔情。但是，它们又有自己神秘的生活方式。它们从不像狗和马一样变得那么顺从。结果是人们已经学会尊重猫的独立性。在它们的一生中，大多数猫都对人存有戒心。最使我们感兴趣的一件事情就是一种通俗的信念——猫有九条命。显然，这种说法里面包含着许多真实性。猫在跌落时能够大难不死是有事实作为依据的。 最近，纽约动物医疗中心对132只猫进行了为期5个月的综合研究。所有这些猫有一个共同的经历：它们都曾从高层建筑上摔下来过，但只有其中的8只猫死于震荡或跌伤。当然，纽约是进行这种有趣的试验的一个理想的地方，因为那里根本不缺乏高楼大厦，有的是高层的窗槛从上往下坠落。有一只叫萨伯瑞的猫从32层楼上掉下来，但只摔断一颗牙。“猫就像训练有素的跳伞队员，” 一位医生说。看起来，猫跌落的距离越长，它们就越不会伤害自己。在一个长长的跌落过程中，它们可以达到每小时60里甚至更快的速度。在高速下落中，猫有时间放松自己。它们伸展四肢，就像飞行中的松鼠一样。这样就加大了空气阻力，并减少了它们着地时冲击力带来的震动。 Lesson 10 The loss of the Titanic “泰坦尼克”号的沉没 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What would have happened if only two of the sixteen water-tight compartments had been flooded? The great ship, Titanic, sailed for New York from Southampton on April 10th, 1912. She was carrying 1,316 passengers and crew of 891. Even by modern standards, the 46,000 ton Titanic was a colossal ship. At the time, however, she was not only the largest ship that had ever been built, but was regarded as unsinkable, for she had sixteen watertight compartments. Even if two of these were flooded, she would still be able to float. The tragic sinking of this great liner will always be remembered, for she went down on her first voyage with heavy loss of life. Four days after setting out, while the Titanic was sailing across the icy water of the North Atlantic, huge iceberg was suddenly spotted by a lookout. After the alarm had been given, the great ship turned sharply to avoid a direct collision. The Titanic turned just in time, narrowly missing the immense walk of ice which rose over 100 feet out of the water beside her. Suddenly, there was a slight trembling sound from below, and the captain went down to see what had happened. The noise had been so faint that no one though that the ship had been damaged. Below, the captain realized to his horror that the Titanic was sinking rapidly, for five of her sixteen watertight compartments had already been flooded! The order to abandon ship was given and hundreds of people plunged into the icy water. As there were not enough lifeboats for everybody, 1,500 lives were lost. New words and expressions 生词和短语 Southampton n. 南安普敦（英国港市） colossal adj. 庞大的 watertight adj. 不漏水的 compartment n. （轮船的）密封舱 flood v. 充满水 float v. 漂浮，飘浮 tragic adj. 悲惨的 liner n. 班船 voyage n. 航行 iceberg n. 冰山 lookout n. 了望员 collision n. 碰撞 narrowly adv. 刚刚，勉强地 miss v. 避开 slight adj. 轻微的 tremble v. 震颤 faint adj. 微弱的 horror n. 恐惧 abandon v. 抛弃 plunge v. 投入，跳入 lifeboat n. 救生船 参考译文 巨轮“泰坦尼克”号1912年4月10日从南安普敦起锚驶向纽约。船上载有1,316名乘客与891名船员。却使用现代标准来衡量，45,000 吨的“泰坦尼克”号与算得上一艘巨轮了。当时，这艘轮船不仅是造船史上建造的最大的一艘船，而且也被认为是不会沉没的。因为船由16个密封舱组成，即使有两个舱进水，仍可漂浮的水面上。然而，这艘巨轮首航就下沉，造成大批人员死亡。人们将永远记着这艘巨轮的沉没惨剧。 “泰坦尼克”起航后的第4天，它正行驶在北大西洋冰冷的海面上。突然，了望员发现一座冰山。警报响过不久，巨轮急转弯，以避免与冰山正面相撞。“泰坦尼克”这个弯拐得及时，紧贴着高出海面100英尺的巨大的冰墙擦过去。突然，从船舱下部传来一声微颤音，船长走下船舱去查看究竟。由于这个声音非常轻，没人会想到船身已遭损坏。在下面，船长惊恐的地发现“泰坦尼克”号正在急速下沉，16个密封舱已有5个进水。于是，他发出弃船的命令，几百人跳进了冰冷刺骨的海水里。由于没有足够的救生艇运载所有乘客，结果，1,500 人丧生。 Lesson 11 Not guilty 无罪 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What was the Customs Officer looking for? Customs Officers are quite tolerant these days, but they can still stop you when you are going through the Green Channel and have nothing to declare. Even really honest people are often made to feel guilty. The hardened professional smuggler, on the other hand, is never troubled by such feelings, even if he has five hundred gold watches hidden in his suitcase. When I returned form abroad recently, a particularly officious young Customs Officer clearly regarded me as a smuggler. 'Have you anything to declare?' he asked, looking me in the eye. 'No', I answered confidently. 'Would you mind unlocking this suitcase please?' 'Not at all,' I answered. The Officer went through the case with great care. All the thing I had packed so carefully were soon in a dreadful mess. I felt sure I would never be able to close the case again. Suddenly, I saw the Officer's face light up. He had spotted a tiny bottle at the bottom of my case and he pounced on it with delight. 'Perfume, eh?' he asked sarcastically. 'You should have declared that. Perfume is not exempt from import duty.' 'But it isn't perfume,' I said. 'It's hair gel.' Then I added with a smile, 'It's a strange mixture I make myself.' As I expected, he did not believe me. 'Try it!' I said encouragingly. The officer unscrewed the cap and put the bottle to his nostrils. He was greeted by an unpleasant smell which convinced him that I was telling the truth. A few minutes later, I was able to hurry away with precious chalk marks on my baggage. New words and expressions 生词和短语 guilty adj. 犯罪的，违法的 tolerant adj. 宽容的 declare v. 申报 hardened adj. 有经验的 professional adj. 职业的，专业的 smuggler n. 走私者 officious adj. 爱管闲事的 confidently adv. 自信地 dreadful adj. 可怕的，一团糟的 pounce v. 猛抓，扑住 perfume n. 香水 sarcastically adv. 讽刺地 exempt adj. 被免除的 duty n. 税 gel n. 凝胶 mixture n. 混合物 unscrew v. 拧开 nostril n. 鼻孔 chalk n. 粉笔 baggage n. 行李 参考译文 现在的海关官员往往相当宽容。但是，当你通过绿色通道，没有任何东西需要申报时，他们仍可以拦住你。甚至是最诚实的人也常弄得觉得有罪似的，而老练的职业走私犯却使手提箱里藏着500只金表，却也处之泰然。最近一次，我也出国归来，碰上一位特别好管闲事的年轻海关官员，他显然把我当成走私犯。 “您有什么需要申报的吗？”他直盯着我的眼睛问。 “没有。”我自信地回答说。 “请打开这只手提箱好吗？” “好的。”我回答说。 那位官员十分仔细地把箱子检查了一遍。所有细心包装好的东西一会儿工夫就乱成一团。我相信那箱子再也关不上了。突然，我看到官员脸上露出了得意的神色。他在我的箱底发现了一只小瓶，高兴地一把抓了起来。 “香水，嗯？”他讥讽地说道，“你刚才应该申报，香水要上进口税的。” “不，这不是香水，”我说，“是发胶。”接着我脸带微笑补充说：“这是一种我自己配制的奇特的混合物。” “你就闻一闻吧！”我催促说。 海关官员拧开瓶盖，把瓶子放到鼻子底下。一股怪味袭来，使他相信了我说的真话。几分钟后，我终于被放行，手提划着宝贵的粉笔记号的行李，匆匆离去。 Lesson 12 Life on a desert island 荒岛生活 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What was exceptional about the two men's stay on the desert island? Most of us have formed an unrealistic picture of life on a desert island. We sometimes imagine a desert island to be a sort of paradise where the sun always shines. Life there is simple and good. Ripe fruit falls from the trees and you never have to work. The other side of the picture is quite the opposite. Life on a desert island is wretched. You either starve to death or live like Robinson Crusoe, Waiting for a boat which never comes. Perhaps there is an element of truth in both these pictures, but few us have had the opportunity to find out. Two men who recently spent five days on a coral island wished they had stayed there longer. They were taking a badly damaged boat from the Virgin Islands to Miami to have it repaired. During the journey, their boat began to sink. They quickly loaded a small rubber dinghy with food, matches, and cans of beer and rowed for a few miles across the Caribbean until they arrived at a tiny coral island. There were hardly any trees on the island and there was no water, but this did not prove to be a problem. The men collected rainwater in the rubber dinghy. As they had brought a spear gun with them, they had plenty to eat. They caught lobster and fish every day，and, as one of them put it 'ate like kings'. When a passing tanker rescued them five days later, both men were genuinely sorry that they had to leave. New words and expressions 生词和短语 desert island 荒岛 unrealistic adj. 不真实 paradise n. 天堂，乐士 wretched adj. 可怜的，艰苦的 starve v. 挨饿 element n. 成分 opportunity n. 机会 coral n. 珊瑚 Virgin Islands 维尔京群岛 Miami n. 迈阿密（美国最南的城市） dinghy n. 救生筏，小船 Caribbean n. 加勒比海 spear gun 捕鱼枪 lobster n. 龙虾 tanker n. 油轮 genuinely adv. 由衷地 Robinson Crusoe 鲁滨孙.克鲁索（小说《鲁滨孙漂流记》主人公） 参考译文 我们许多人对于荒岛生活有一种不切实际的想法。我们有时想象荒岛是阳光终日普照的天堂。在那里，生活简单又美好。成熟的水果从树上掉下来，人们根本无需劳动。另一种想法恰恰相反，认为荒岛生活很可怕，要么饿死，要么像鲁滨孙那样，天天盼船来，却总没见船影。也许，这两种都像都有可信之处。但很少有人能有机会去弄个究竟。 最近有两个人在一座珊瑚岛上呆了5天，他们真希望在那儿再多呆一些日子。他们驾着一条严重损坏的小船从维尔京群岛阿密修理。途中，船开始下沉，他们迅速把食物、火柴、罐装啤酒往一只救生筏上装。然后在加勒比海上划行了几英里，到了一座珊瑚岛上。岛上几乎没有一颗树，也没有淡水，但这不算什么问题。他们用像皮艇蓄积雨水。由于他们随身带了一支捕鱼枪，因此，吃饭不愁。他们天天捕捉龙虾和鱼，正如其中一位所说，吃得“像国王一样好”。5天后，一条油轮从那儿路过，搭救了他们。这二位不得不离开那个荒岛时，还真的感到遗憾呢！ Lesson 13 "It's only me' “是我，别害怕” Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What did the man expect to find under the stairs? After her husband had gone to work. Mrs. Richards sent her children to school and went upstairs to her bedroom. She was too excited to do any housework that morning, for in the evening she would be going to a fancy-dress part with her husband. She intended to dress up as a ghost and as she had made her costume the night before, she was impatient to try it on. Though the costume consisted only of a sheet, it was very effective. After putting it on, Mrs. Richards went downstairs. She wanted to find out whether it would be comfortable to wear. Just as Mrs. Richards was entering the dinning room, there was a knock on the front door. She knew that it must be the baker. She had told him to come straight in if ever she failed to open the door and to leave the bread on the kitchen table. Not wanting to frighten the poor man, Mrs. Richards quickly hid in the small storeroom under the stairs. She heard the front door open and heavy footsteps in the hall. Suddenly the door of the storeroom was opened and a man entered. Mrs. Richards realized that it must be the man from the Electricity Board who had come to read the metre. She tried to explain the situation, saying 'It's only me', but it was too late. The man let out cry and jumped back several paces. When Mrs. Richards walked towards him, he fled, slamming the door behind him. New words and expressions 生词和短语 costume n. 化装服 consist v. 由……组成 sheet n. 被单 effective adj. 有明显效果的，有作用的 metre n. 电表 pace n. 一步 lee (fled, fled) v. 逃走 slam v. 砰地关上 参考译文 理查兹夫人等丈夫上班走后，把孩子送去上学，然后来到楼上自己的卧室。那天上午，她兴奋得什么家务活都不想做，因为晚上她要同丈夫一起参加一个化装舞会。她打算装扮成鬼的模样。头天晚上她已把化装服做好，这时她急于想试试。尽管化装服仅由一个被单制成，却十分逼真。理查兹夫人穿上化装服后下了楼，想看穿起来是否舒服。 理查兹夫人刚刚走进餐厅，前门就传来敲门声。她知道来了一定面包师。她曾告诉过面包师，如果她不去开门，他可直接进门，把面包放在厨房的桌上。理查兹夫人不想吓唬这个可怜人，便赶紧躲到了楼梯下的小储藏室里。她听见前门被打开，走廊里响起重重的脚步声。突然贮藏门开了，一个男人走了进来。理查兹夫人这才想到一定是供电局来人查电表了。她说了声“是我，别怕！”然后想进行一番解释，但已来不及了。那人大叫了一声，惊退了几步。理查兹夫人朝他走去，只见他“砰”的一声关上门逃走了。 Lesson 14 A noble gangster 贵族歹徒 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 How did Haywood make in times of peace? There was a tine when the owners of shops and businesses in Chicago that to pay large sums of money to gangsters in return for 'protection.' If the money was not paid promptly, the gangsters would quickly put a man out of business by destroying his shop. Obtaining 'protection money' is not a modern crime. As long ago as the fourteenth century, an Englishman, Sir John Hawkwood, made the remarkable discovery that people would rather pay large sums of money than have their life work destroyed by gangsters. Six hundred years ago, Sir Johan Hawkwood arrived in Italy with a band of soldiers and settled near Florence. He soon made a name for himself and came to be known to the Italians as Giovanni Acuto. Whenever the Italian city-states were at war with each other, Hawkwood used to hire his soldiers to princes who were willing to pay the high price he demanded. In times of peace, when business was bad, Hawkwood and his men would march into a city-state and, after burning down a few farms, would offer to go away protection money was paid to them. Hawkwood made large sums of money in this way. In spite of this, the Italians regarded him as a sort of hero. When he died at the age of eighty, the Florentines gave him a state funeral and had a pictured with as dedicated to the memory of 'the most valiant soldier and most notable leader, Signor Giovanni Haukodue.' New words and expressions 生词和短语 gangster n. 歹徒,强盗 Chicago n. 芝加哥(美国城市) protection n. 保护 promptly adv. 准时地 destroy v. 毁掉;消灭 remarkable adj. 不寻常的 hand n. 帮,团伙 Florence n. 佛罗伦萨(意大利城市) city-state n. (古代)城邦 hire v. 租出,雇给 prince n. 君主,诸候 Florentine n. 佛罗伦萨人 funeral n. 葬礼 dedicate v. 奉献,题献给 memory n. 纪念 valiant adj. 英勇的 参考译文 曾经有一个时期,芝加哥的店主和商行的老板们不得不拿出大笔的钱给歹徒以换取"保护"。如果交款不及时,歹徒们就会很快捣毁他的商店,让他破产.榨取"保护金"并不是一种现代的罪恶行径.早在14世纪,英国人约翰.霍克伍德就有过非凡的发现:"人们情愿拿出大笔的钱,也不愿毕生的心血毁于歹徒之手. 600年前,约翰.霍克伍德爵士带着一队士兵来到意大利,在佛罗伦萨附近驻扎下来,很快就出了名.意大利人叫他乔凡尼.阿库托.每次意大利各城邦之间打伏,霍克伍德把他的士兵雇佣给愿给他出高价的君主。和平时期,当生意萧条时,霍克伍德便带领士兵进入某个城邦,纵火烧毁一两个农场,然后提出,如向他们缴纳保护金,他们便主动撤离。霍克伍德用这种方法挣了大笔钱.尽管如此,意大利人还是把他视作某种英雄。他80岁那年死去时,佛罗伦萨人为他举行了国葬,并为他画像以纪念这位"骁勇无比的战士、杰出的领袖乔凡尼.阿库托先生." Lesson 15 Fifty pence worth of trouble 五十便士的麻烦 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Did George get anything for his fifty pence? What? Children always appreciate small gifts of money. Mum or dad, of course, provide a regular supply of pocket money, but uncles and ants are always a source of extra income. With some children, small sums go a long way. If fifty pence pieces are not exchanged for sweets, they rattle for months inside money boxes. Only very thrifty children manage to fill up a money box. For most of them, fifty pence is a small price to pay for a nice big bar of chocolate. My nephew, George, has a money box but it is always empty. Very few of the fifty pence pieces and pound coins I have given him have found their way there. I gave him fifty pence yesterday and advised him to save it. Instead he bought himself fifty pence worth of trouble. On his way to the sweet shop, he dropped his fifty pence and it bounced along the pavement and then disappeared down a drain. George took off his jacket, rolled up his sleeves and pushed is right arm through the drain cover. He could not find his fifty pence piece anywhere, and what is more, he could no get his arm out. A crowd of people gathered round him and a lady rubbed his arm with soap and butter, but George was firmly stuck. The fire brigade was called and two fire fighter freed George using a special type of grease. George was not too upset by his experience because the lady who owns the sweet shop heard about his troubles and rewarded him with large box of chocolates. New words and expressions 生词和短语 appreciate v. 欣赏，感激 pocket money 零用钱 thrifty adj. 节约的 nephew n. 侄子，外甥 bounce v. 弹起，跳起 pavement n. 人行道 stick (stuck, stuck) v. 卡住，夹住，不能再动 brigade n. 旅，（消防）队 grease n. 润滑油 参考译文 孩子们总是喜欢得到一些零花钱。爸爸妈妈当然经常给孩子零花钱，但是，叔舅婶姨也是孩子们额外收入来源。对于有些孩子来说，少量的钱可以花很长一段时间。如果50便士不拿来换糖吃，则可以放在储蓄罐里叮当响上好几月。但是能把储蓄罐装满的只有屈指可数的几个特别节俭的孩子。对大部分孩子来说，用50便士来买一大块好的巧克力，是算不了什么的。 我的外甥乔治有一个储蓄罐，但总是空空的。我给了不少50便士的硬币，但没有几个存到储蓄罐里。昨天，我给了他50便士让存起来，却拿这钱给自己买了50便士的麻烦。在他去糖果店的路上，50便士掉在地上，在人行道上跳了几下，掉进了阴沟里。乔治脱掉外套，卷起袖子，将右胳膊伸进了阴沟盖。但他摸了半天也没找到那50便士硬币，他的胳膊反倒退不出来了。这时在他周围上了许多人，一位女士在乔治胳膊上抹了肥皂，黄油，但乔治的胳膊仍然卡得紧紧的。有人打电话叫来消防队，两位消防队员使用了一种特殊的润滑剂才使乔治得以解脱。不过，此事并没使乔治过于伤心，因为糖果店老板娘听说了他遇到的麻烦后，赏给他一大盒巧克力。 Lesson 16 Mary had a little lamb 玛丽有一头羔羊 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Was Dimitri right to apologize to his neighbour? Why not? Mary and her husband Dimitri lived in the tiny village of Perachora in southern Greece. One of Mary's prize possessions was a little white lamb which her husband had given her. She kept it tied to a tree in a field during the day and went to fetch it every evening. One evening, however, the lamb was missing. The rope had been cut, so it was obvious that the lamb had been stolen. When Dimitri came in from the fields, his wife told him what had happened. Dimitri at once set out to find the thief. He knew it would not prove difficult in such a small village. After telling several of his friends about the theft, Dimitri found out that his neighbour, Aleko, had suddenly acquired a new lamb. Dimitri immediately went to Aleko's house and angrily accused him of stealing the lamb. He told him he had better return it or he would call the police. Aleko denied taking it and led Dimitri into his backyard. It was true that he had just bought a lamb, he explained, but his lamb was black. Ashamed of having acted so rashly, Dimitri apologized to Aleko for having accused him. While they were talking it began to rain and Dimitri stayed in Aleko's house until the rain stopped. When he went outside half an hour later, he was astonished to find the little black lamb was almost white. Its wool, which had been dyed black, had been washed clean by the rain! New words and expressions 生词和短语 prize adj. 珍贵的，宝贵的 tie v. 拴，系 theft n. 偷盗行为，偷盗案 accuse v. 指控 deny v. 否认 ashamed adj. 感到羞耻，惭愧 apologize v. 道歉 dye v. 染 参考译文 玛丽与丈夫迪米特里住在希腊南部一个叫波拉考拉的小村庄里。玛丽最珍贵的财产之一就是丈夫送给她的一只白色小羔羊。白天，玛丽把羔羊拴在地里的一颗树上，每天晚上把它牵回家。可是，一天晚上，那只小羔羊失踪了。绳子被人割断，很明显小羔羊是被人偷走了。 迪米特里从地里回来，妻子把情况跟他一说，他马上出去找偷羔羊的人。他知道在这样一个小村庄里抓住小偷并不困难。把失窃的事告诉几个朋友后，迪米特里发出他的邻居阿列科家突然多了一只小羔羊。迪米特里立刻去了阿列科家，气呼呼地指责他偷了羔羊，告诉他最好把羊交还，否则就去叫警察。阿列科不承认，并把迪米特里领进院子。不错，他的确刚买了一只羔羊，阿列科解释说，但他的羔羊是黑色的。迪米特里为自己的鲁莽而感到不好意思，向阿列科道了歉，说是错怪了他。就在他俩说话的时候，天下起了雨，迪米特里便呆在阿列科家里避雨，一直等到雨停为止。半小时后，当他从屋里出来时，他惊奇地发现小黑羔羊全身几乎都变成白色。原来羊毛上染的黑色被雨水冲掉了！ Lesson 17 The longest suspension bridge in the world 世界上最长的吊桥 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 How is the bridge supported? Verrazano, an Italian about whom little is known, sailed into New York Harbour in 1524 and named it Angouleme. He described it as 'a very agreeable situation located within two small hills in the midst of which flowed a great river.' Though Verrazano is by no means considered to be a great explorer, his name will probably remain immortal, for on November 21st, 1964, the longest suspension bridge in the world was named after him. The Verrazano Bridge, which was designed by Othmar Ammann, joins Brooklyn to Staten Island. It has a span of 4,260 feet. The bridge is so long that the shape of the earth had to be taken into account by its designer. Two great towers support four huge cables. The towers are built on immense underwater platforms make of steel and concrete. The platforms extend to a depth of over 100 feet under the sea. These alone took sixteen months to build. Above the surface of the water, the towers rise to a height of nearly 700 feet. They support the cables from which the bridge has been suspended. Each of the four cables contains 26,108 lengths of wire. It has been estimated that if the bridge were packed with cars, it would still only be carrying a third of its total capacity. However, size and strength are not the only important things about this bridge. Despite its immensity, it is both simple and elegant, fulfilling its designer's dream to create 'an enormous object drawn as faintly as possible'. New words and expressions 生词和短语 suspension n. 悬，吊 agreeable adj. 宜人的 situation n. 地点，地方 locate v. 位于 immortal adj. 永生的，流芳百世的 Brooklyn n. 布鲁克林（纽约一区名） Staten n. 斯塔顿（岛） span n. 跨度 cable n. 缆索 concrete n. 混凝土 suspend v. 悬挂 length n. 根，段 estimate v. 估计 capacity n. 承受量 immensity n. 巨大 elegant adj. 优美别致的 faintly adv. 微细地 参考译文 1524年，一位鲜为人知的意大利人维拉萨诺驾船驶进纽约港，并将该港名为安古拉姆。他对该港作了这样的描述：“地理位置十分适宜，位于两座小山的中间，一条大河从中间流过”。虽然维拉萨诺绝对算不上一个伟大的探险家，但他的名字将流芳百世，因为1964年11月21日建成的一座世界上最长的吊桥是以他的名字命名。 维拉萨诺大桥由奥斯马.阿曼设计，连结着布鲁克林与斯塔顿岛，桥长4,260英尺。由于桥身太长，设计者不得不考虑了地表的形状。两座巨塔支撑着4根粗大的钢缆。塔身建在巨大的水下钢盘混凝土平台上。平台深入海底100英尺。仅这两座塔就花了16个月才建成。塔身高出水面将近700英尺。高塔支撑着钢缆，而钢缆又悬吊着大桥，4根钢缆中的每根由26，108股钢绳组成。据估计，若桥上摆满了汽车，也只不过是桥的总承载力的1/3。然而，这座桥重要特点不仅是它的规模与强度。尽管此桥很大，但它的结构简单，造型优美，实现了设计者企图创造一个“尽量用细线条勾画出一个庞然大物”的梦想。 Lesson 18 Electric currents in modern art 现代艺术的电流 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 How might some of the exhibits have been dangerous? Modern sculpture rarely surprises us any more. The idea that modern art can only be seen in museums is mistaken. Even people who take no interest in art cannot have failed to notice examples of modern sculpture on display in public places. Strange forms stand in gardens, and outside buildings and shops. We have got quite used to them. Some so-called 'modern' pieces have been on display for nearly eighty years. In spite of this, some people -- including myself -- were surprise by a recent exhibition of modern sculpture. The first thing I saw when I entered the art gallery was a notice which said: 'Do not touch the exhibits. Some of them are dangerous!' The objects on display were pieces of moving sculpture. Oddly shaped forms that are suspended form the ceiling and move in response to a gust of wind are quite familiar to everybody. These objects, however, were different. Lined up against the wall, there were long thin wires attached to metal spheres. The spheres had been magnetized and attracted or repelled each other all the time. In the centre of the hall, there were a number of tall structures which contained coloured lights. These lights flickered continuously like traffic lights which have gone mad. Sparks were emitted from small black boxes and red lamps flashed on and off angrily. It was rather like an exhibition of prehistoric electronic equipment. These peculiar forms not only seemed designed to shock people emotionally, but to give them electric shocks as well! New words and expressions 生词和短语 current n. 电流 sculpture n. 雕塑 mistaken adj. 错误的 gallery n. 美术馆 exhibit n. 展品，陈列品 oddly adv. 古怪的 attach v. 连，系 sphere n. 球体 magnetize v. 使磁化 repel v. 排斥 flicker v. 闪烁 emit v. 放射 flash v. 闪光 prehistoric adj. 史前的，老掉牙的 electronic adj. 电子的 peculiar adj. 奇异的 shock v. 令人震惊，刺激人 emotionally adv. 事情上 参考译文 现代雕塑不再使我们感到惊讶了。那种认为现代艺术只能在博物馆里才能看到的观点是错误的。即使是对艺术不感兴趣的人也不会注意到在公共场所展示的现代艺术品。公园里、大楼和商店外竖立着的奇形怪状的雕塑，对这些，我们已经司空见惯了。有些所谓的“现代”艺术品在那里已经陈列了近80年了。 尽管如此，最近举办的一次现代雕塑展览还是使一些人（包括我在内）大吃了一惊。走进展厅首先看到的是一张告示，上面写着“切勿触摸展品，某些展品有危险！”展品都是些活动的雕像。人们所熟悉的是悬挂在天花板上、造型奇特、随风飘荡的雕塑品。这些展品却使人大开眼界。靠墙排列着许多细长的电线，而电线又连着金属球。金属球经过磁化，互相之间不停地相互吸引或相互排斥。展厅中央是装有彩色灯泡的许多高高的构件，灯泡一刻不停地闪烁着，就像失去了控制的红绿灯。小黑盒子里迸出火花，红色灯泡发怒似地忽明忽暗。这儿倒像是在展览古老的电子设备。好像设计这些奇形怪状的展品不仅是为了给人感情上的强烈刺激，而且还想给人以电击似的！ Lesson 19 A very dear cat 一条贵重的宝贝猫 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Why was Rastus 'very dear' in more ways than one? Kidnappers are rarely interested in animals, but they recently took considerable interest in Mrs. Eleanor Ramsay's cat. Mrs. Eleanor Ramsay, a very wealthy old lady, has shared a flat with her cat, Rastus, for a great many years. Rastus leads an orderly life. He usually takes a short walk in the evenings and is always home by seven o'clock. One evening, however, he failed to arrive. Mrs. Ramsay got very worried. She looked everywhere for him but could not find him. There days after Rastus' disappearance, Mrs. Ramsay received an anonymous letter. The writer stated that Rastus was in safe hands and would be returned immediately if Mrs. Ramsay paid a ransom of$1,000. Mrs. Ramsay was instructed to place the money in a cardboard box and to leave it outside her door. At first she decided to go to the police, but fearing that she would never see Rastus again -- the letter had made that quite clear -- she changed her mind. She withdrew $1000 from her bank and followed the kidnapper's instructions. The next morning, the box had disappeared but Mrs. Ramsay was sure that the kidnapper would keep his word. Sure enough, Rastus arrived punctually at seven o'clock that evening. He looked very well though he was rather thirsty, for he drank half a bottle of milk. The police were astounded when Mrs. Ramsay told them what she had done. She explained that Rastus was very dear to her. Considering the amount she paid, he was dear in more ways than one! New words and expressions 生词和短语 dear adj. 亲爱的，珍贵的；昂贵的 kidnapper n. 绑架者，拐骗者 considerable adj. 相当大的 wealthy adj. 富的，有钱的 orderly adj. 有规律的 disappearance n. 失踪 anonymous adj. 匿名的 ransom n. 赎金 cardboard n. 硬纸板 withdraw(withdrew, withdrawn) v. （从银行）取钱 punctually adv. 准时地 astound v. 使吃惊 参考译文 绑架者很少对动物感兴趣。最近，绑架者却盯上了埃莉诺.拉姆齐太太的猫。埃莉诺.拉姆齐太太是一个非常富有的老妇人，多年来，一直同她养的猫拉斯一起住在一所公寓里。拉斯特斯生活很有规律，傍晚常常出去溜达一会儿，并且总是在7点钟以前回来。可是，有一天晚上，它出去后再也没回来。拉姆齐太太急坏了，四处寻找，但没有找着。 拉斯特斯失踪3天后，拉姆齐太太收到一封匿名信。写信人声称拉斯特斯安然无恙，只要拉姆齐太太愿意支付1,000 英镑赎金，可以立即将猫送还。他让拉姆齐太太把钱放在一个纸盒里，然后将纸盒放在门口。一开始拉姆齐太太打算报告警察，但又害怕再也见不到拉斯特斯——这点，信上说得十分明白——于是便改变了主意。她从银行取出1,000 英镑，并照绑架者的要求做了。第二天早晨，放钱的盒子不见了。但拉姆齐太太确信绑架者是会履行诺言的。果然，当天晚上7点正，拉斯特斯准时回来了。它看上去一切正常，只是口渴得很，喝了半瓶牛奶。拉姆齐太太把她所做的事告诉了警察，警察听后大为吃惊。拉姆齐太太解释说她心疼她的猫拉斯特斯。想到她所花的那笔钱，她的心疼就具有双重意义了。 Lesson 20 Pioneer pilots 飞行员的先驱 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What was the name of the first plane to fly across the English Channel? In 1908 Lord Northcliffe offered a prize of$1,000 to the first man who would fly across the English Channel. Over a year passed before the first attempt was made. On July 19th, 1909, in the early morning, Hubert Latham took off from the French coast in his plane the 'Antoinette IV.' He had travelled only seven miles across the Channel when his engine failed and he was forced to land on sea. The 'Antoinette' floated on the water until Latham was picked up by a ship.
Two days alter, Louis Bleriot arrived near Calais with a plane called 'No. XI'. Bleriot had been making planes since 1905 and this was his lattes model. A week before, he had completed a successful overland flight during which he covered twenty-six miles. Latham, however, did not give up easily. He, too, arrived near Calais on the same day with a new 'Antoinette'. It looked as if there would be an exciting race across the Channel. Both planes were going to take off on July 25th, but Latham failed to get up early enough, After making a short test flight at 4,15 a.m., Bleriot set off half an hour later. His great flight lasted thirty-seven minutes. When he landed near Dover, the first person to greet him was a local policeman. Latham made another attempt a week later and got within half a mile of Dover, but he was unlucky again. His engine failed and he landed on the sea for the second time.
New words and expressions 生词和短语
pioneer
n. 先驱
lord
n. 对（英国）贵族的尊称；勋爵
Calais
n. 加来（法国港市）
overland
1908年，诺斯克利夫勋爵拿出1,000英镑，作为对第一个飞越英吉利海峡的人的奖励。然而一年多过去了才有人出来尝试。1909年7月19日凌晨，休伯特.莱瑟姆驾驶“安特瓦特4号”飞机从法国海岸起飞，但他只在海峡上空飞行7英里，引擎就发生了故障，他只好降落在海面上。“安特瓦特”号飞机在海上漂浮，后来有船经过，莱瑟姆方才获救。
两天之后，路易斯.布莱里奥驾驶一名为“11号”的飞机来到加来附近。布莱里奥从1905年起便开始研制飞机，“11号”飞机是他制作的最新型号。一周以前，他曾成功地进行了一次26英里的陆上飞行。但是莱瑟姆不肯轻易罢休。同一天，他驾驶一架新的“安特瓦特”号飞机来到了加来附近。看来会有一场激烈的飞越英吉利海峡的竞争。两天飞机都打算在7月25日起飞，但莱瑟姆那天起床晚了。布莱里奥凌晨4点15分作了一次短距离试飞，半小时后便正式出发了。他这次伟大的飞行持续37分钟。当他在多佛着陆后，第一个迎接他的是当地一名警察。莱瑟姆一周以后也作了一次尝试，飞到离多佛不到半英里的地方。这次他又遭厄运，因引擎故障第二次降落在海面上。
Lesson 21
Daniel Mendoza
丹尼尔.门多萨
Listen to the tape then answer the question below.
How many unsuccessful attempts did Mendoza make before becoming Champion of all England?
Boxing matches were very popular in England two hundred years ago. In those days, boxers fought with bare fists for prize money. Because of this, they were known as 'prizefighters'. However, boxing was very crude, for these were no rules and a prizefighter could be seriously injured or even killed during a match.
One of the most colourful figures in boxing history was Daniel Mendoza, who was born in 1764. The use of gloves was not introduced until 1860, when the Marquis of Queensberry drew up the first set of rules. Though he was technically a prizefighter, Mendoza did much to change crude prizefighting into a sport, for he brought science to the game. In this day, Mendoza enjoyed tremendous popularity. He was adored by rich and poor alike.
Mendoza rose to fame swiftly after a boxing match when he was only fourteen years old. This attracted the attention of Richard Humphries who was then the most eminent boxer in England. He offered to train Mendoza and his young pupil was quick to learn. In fact, Mendoza soon became so successful that Humphries turned against him. The two men quarrelled bitterly and it was clear that the argument could only be settled by a fight. A match was held at Stilton, where both men fought for an hour. The public bet a great deal of money on Mendoza, but he was defeated. Mendoza met Humphries in the ring on a later occasion and he lost for a second time. It was not until his third match in 1790 that he finally beat Humphries and became Champion of England. Meanwhile, he founded a highly successful Academy and even Lord Byron became one of his pupils. He earned enormous sums of money and was paid as much as $100 for a single appear one of his pupils. He earned enormous sums of money and was paid as much as$100 for a single appearance. Despite this, he was so extravagant that he was always in debt. After he was defeated by a boxer called Gentleman Jackson, he was quickly forgotten. He was sent to prison for failing to pay his debts and died in poverty in 1836.
New words and expressions 生词和短语
Boxing
n. 拳击
boxer
n. 拳击手
bare
prizefighter
n. 职业拳击手（尤指古时赤手拳击手）
crude
marquis
n. 侯爵
technically
science
n. 科学
popularity
n. 名望
v. 崇拜，爱戴
alike
fame
n. 名声
eminent
bitterly
bet
v. 打赌
n. 专业学校
extravagant
poverty
n. 贫困
两百年前，拳击比赛在英国非常盛行。当时，拳击手们不戴手套，为争夺奖金而搏斗。因此，他们被称作“职业拳击手”。不过，拳击是十分野蛮的，因为当时没有任何比赛规则，职业拳击手有可能在比赛中受重伤，甚至丧命。
拳击史上最引人注目的人物之一是丹尼尔.门多萨，他生于1764年。1860年昆斯伯里侯爵第一次为拳击比赛制定了规则，拳击比赛这才用上了手套。虽然门多萨严格来讲不过是个职业拳击手，但在把这种粗野的拳击变成一种体育运动方面，他作出了重大贡献。是他把科学引进了这项运动。门多萨在的全盛时期深受大家欢迎，无论是富人还是穷人都对他祟拜备至。
门多萨在14岁时参加一场拳击赛后一举成名。这引起当时英国拳坛名将理查德.汉弗莱斯的注意。他主动提出教授门多萨，而年少的门多萨一学就会。事实上，门多萨不久便名声大振，致使汉弗莱斯与他反目为敌。两个人争吵不休，显而易见，只有较量一番才能解决问题。于是两人在斯蒂尔顿设下赛场，厮打了一个小时。公众把大笔赌注下到了门多萨身上，但他却输了。后来，门多萨与汉弗莱斯再次在拳击场上较量，门多萨又输了一场。直到1790年他们第3次对垒，门多萨才终于击败汉弗莱斯，成了全英拳击冠军。同时，他建立了一所拳击学校，办得很成功，连拜伦勋爵也成了他的学生。门多萨挣来大笔大笔的钱，一次出场费就多可达100英镑。尽管收入不少，但他挥霍无度，经常债台高筑。他在被一个叫杰克逊绅士的拳击手击败后很快被遗忘。他因无力还债而被捕入狱，最后于1836年在贫困中死去。
Lesson 22
By heart
熟记台词
Listen to the tape then answer the question below.
Which actor read the letter in the end, the aristocrat or the gaoler?
Some plays are so successful that they run for years on end, In many ways, this is unfortunate for the poor actors who are required to go on repeating the same lines night after night. One would expect them to know their parts by heart and never have cause to falter. Yet this is not always the case.
A famous actor in a highly successful play was once cast in the role of an aristocrat who had been imprisoned in the Bastille for twenty years. In the last act, a gaoler would always come on to the stage with a letter which he would hand to the prisoner. Even though the noble was expected to read the letter at each performance, he always insisted that it should be written out in full.
One night, the gaoler decided to play a joke on his colleague to find out if, after so many performances, he had managed to learn the contents of the letter by heart. The curtain went up on the final act of the play and revealed the aristocrat sitting alone behind bars in his dark cell. Just then, the gaoler appeared with the precious letter in his bands. He entered the cell and presented the letter to the aristocrat. But the copy he gave him had not been written out in full as usual. It was simply a blank sheet of paper. The gaoler looked on eagerly, anxious to see if his fellow actor had at last learnt his lines. The noble stared at the blank sheet of paper for a few seconds. Then, squinting his eyes, he said: 'The light is dim. Read the letter to me'. And he promptly handed the sheet of paper to the gaoler. Finding that he could not remember a word of the letter either, the gaoler replied: 'The light is indeed dim, sire, I must get my glasses.' With this, he hurried off the stage. Much to the aristocrat's amusement, the gaoler returned a few moments later with a pair of glasses and the usual copy of the letter with he proceeded to read to the prisoner.
New words and expressions 生词和短语
run (ran, run)
v. （戏剧，电影等）连演，连映
lines
n. （剧本中的）台词
part
n. 剧中的角色，台词
falter
v. 支吾，结巴说
cast (cast, cast)
v. 连派……扮演角色
role
n. 角色
aristocrat
n. 贵族
imprison
v. 关押
Bastille
n. 巴士底狱
gaoler
n. 监狱长，看守
colleague
n. 同事
curtain
n. （舞台上的）幕布
reveal
v. 使显露
cell
n. 单人监房，监号
blank
squint
v. 眯着（眼）看，瞄
dim
sire
n. （古用法）陛下
proceed
v. 继续进行
有些剧目十分成功，以致连续上演好几年。这样一来，可怜的演员们可倒霉了。因为他们需要一夜连着一夜地重复同样的台词。人们以为，这些演员一定会把台词背得烂熟，绝不会临场结巴的，但情况却并不总是这样。
有一位名演员曾在一出极为成功的剧目中扮演一个贵族角色，这个贵族已在巴士底狱被关押了20年。在最后一幕中，狱卒手持一封信上场，然后将信交给狱中那位贵族。尽管那个贵族每场戏都得念一遍那封信。但他还是坚持要求将信的全文写在信纸上。
一天晚上，狱卒决定与他的同事开一个玩笑，看看他反复演出这么多场之后，是否已将信的内容记熟了。大幕拉开，最后一幕戏开演，贵族独自一人坐在铁窗后阴暗的牢房里。这时狱卒上场，手里拿着那封珍贵的信。狱卒走进牢房，将信交给贵族。但这回狱卒给贵族的信没有像往常那样把全文写全，而是一张白纸。狱卒热切地观察着，急于想了解他的同事是否记熟了台词。贵族盯着纸看了几秒钟，然后，眼珠一转，说道：“光线太暗，请给我读一下这封信。”说完，他一下子把信递给狱卒。狱卒发现自己连一个字也记不住，于是便说：“陛下，这儿光线的确太暗了，我得去眼镜拿来。”他一边说着，一边匆匆下台。贵族感到非常好笑的是：一会儿工夫，狱卒重新登台，拿来一副眼镜以及平时使用的那封信，然后为那囚犯念了起来。
Lesson 23
One man's meat is
another man's poison
各有所爱
Listen to the tape then answer the question below.
What was it about snails that made the writer collect them for his friend on that in particular?
People become quite illogical when they try to decide what can be eaten and what cannot be eaten. If you lived in the Mediterranean, for instance, you would consider octopus a great delicacy. You would not be able to understand why some people find it repulsive. On the other hand, your stomach would turn at the idea of frying potatoes in animal fat -- the normally accepted practice in many northern countries. The sad truth is that most of us have been brought up to eat certain foods and we stick to them all our lives.
No creature has received more praise and abuse than the common garden snail. Cooked in wine, snails are a great luxury in various parts of the world. There are countless people who, ever since their early years, have learned to associate snails with food. My friend, Robert, lives in a country where snails are despised. As his flat is in a large town, he has no garden of his own. For years he has been asking me to collect snails from my garden and take them to him. The idea never appealed to me very much, but one day, after heavy shower, I happened to be walking in my garden when I noticed a huge number of snails taking a stroll on some of my prize plants. Acting on a sudden impulse, I collected several dozen, put them in a paper bag, and took them to Robert. Robert was delighted to see me and equally pleased with my little gift. I left the bag in the hall and Robert and I went into the living room where we talked for a couple of hours. I had forgotten all about the snails when Robert suddenly said that I must stay to dinner. Snails would, of course, be the main dish. I did not fancy the idea and I reluctantly followed Robert out of the room. To our dismay, we saw that there were snails everywhere: they had escaped from the paper bag and had taken complete possession of the hall! I have never been able to look at a snail since then.
New words and expressions 生词和短语
poison (title)
n. 毒药
illogical
octopus
n. 章鱼
delicacy
n. 美味，佳肴
repulsive
stomach
n. 胃
turn
v. 感到恶心，翻胃
fry
v. 油炸
fat
n. （动物，植物）油
abuse
n. 辱骂，责骂
snail
n. 蜗牛
luxury
n. 奢移品，珍品
associate
v. 联想到
despise
v. 鄙视
appeal
v. 引起兴致
shower
n. 阵雨
stroll
n. 溜达，散步
impulse
n. 冲动
dozen
n. 12个，一打
fancy
v. 喜爱，喜欢
在决定什么能吃而什么不能吃的时候，人们往往变得不合情理。比如，如果你住在地中海地区，你会把章鱼视作是美味佳肴，同时不能理解为什么有人一见章鱼就恶心。另一方面，你一想到动物油炸土豆就会反胃，但这在北方许多国家却是一种普通的烹任方法。不无遗憾的是， 我们中的大部分人，生来就只吃某几种食品，而且一辈子都这样。
没有一种生物所受到的赞美和厌恶会超过花园里常见的蜗牛了。蜗牛加酒烧煮后，便成了世界上许多地方的一道珍奇的名菜。有不计其数的人们从小就知道蜗牛可做菜。但我的朋友罗伯特却住在一个厌恶蜗牛的国家中。他住在大城市里的一所公寓里，没有自己的花园。多年来，他一直让我把我园子里的蜗牛收集起来给他捎去。一开始，他的这一想法没有引起我多大兴趣。后来有一天，一场大雨后，我在花园里漫无目的散步，突然注意到许许多多蜗牛在我的一些心爱的花木上慢悠悠的蠕动着。我一时冲动，逮了几十只，装进一只纸袋里，带着去找罗伯特。罗伯特见到我很高兴，对我的薄礼也感到满意。我把纸袋放在门厅里，与罗伯特一起进了起居室，在那里聊了好几个钟头。我把蜗牛的事已忘得一干二净，罗伯特突然提出一定要我留下来吃晚饭，这才提醒了我。蜗牛当然是道主菜。我并不喜欢这个主意，所以我勉强跟着罗伯特走进了起居室。使我们惊愕的是门厅里到处爬满了蜗牛：它们从纸袋里逃了出来，爬得满厅都是！从那以后，我再也不能看一眼蜗牛了。
Lesson 24
A skeleton in the cupboard
“家丑”
Listen to the tape then answer the question below.
Who was Sebastian?
We often read in novels how a seemingly respectable person or family has some terrible secret which has been concealed from strangers for years. The English language possesses a vivid saying to describe this sort of situation. The terrible secret is called 'a skeleton in the cupboard'. At some dramatic moment in the story, the terrible secret becomes known and a reputation is ruined. The reader's hair stands on end when he reads in the final pages of the novel that the heroine a dear old lady who had always been so kind to everybody, had, in her youth, poisoned every one of her five husbands.
It is all very well for such things to occur in fiction. To varying degrees, we all have secrets which we do not want even our closest friends to learn, but few of us have skeletons in the cupboard. The only person I know who has a skeleton in the cupboard is George Carlton, and he is very pound of the fact. George studied medicine in his youth. Instead of becoming a doctor, however, he became a successful writer of detective stories. I once spend an uncomfortable weekend which I shall never forget at his house. George showed me to the guestroom which, he said, was rarely used. He told me to unpack my things and then come down to dinner. After I had stacked my shirts and underclothes in two empty drawers, I decided to hang one of the tow suits I had brought with me in the cupboard. I opened the cupboard door and then stood in front of two suits I had brought with me in the cupboard. I opened the cupboard door and then stood in front of it suits I had brought with me in the cupboard. I opened the cupboard door and then stood in front of it petrified. A skeleton was dangling before my eyes. The sudden movement of the door made it sway slightly and it gave me the impression that it was about to leap out at me. Dropping my suit, I dashed downstairs to tell George. This was worse than "a terrible secret'; this was a read skeleton! But George was unsympathetic. 'Oh, that,' he said with a smile as if he were talking about an old friend. 'That's Sebastian. You forget that I was a medical student once upon a time.'
New words and expressions 生词和短语
skeleton
n. 骷髅
seemingly
respectable
conceal
v. 隐藏，隐瞒
vivid
dramatic
ruin
v. 毁坏
heroine
n. 女主人公
fiction
n. 小说
varying
medicine
n. 医学
guestroom
n. （家庭中的）来客住房
unpack
vt. （从箱中）取出
stack
v. （整齐地）堆放，排放
underclothes
n. 内衣
drawer
n. 抽屉
petrify
v. 使惊呆
dangle
v. 悬挂
sway
v. 摇摆
unsympathetic
medical
在小说中，我们经常读到一个表面上受人尊重的人物或家庭，却有着某种多年不为人所知的骇人听闻的秘密。英语中有一个生动的说法来形容这种情况。惊人的秘密称作“柜中骷髅”。在小说的某个戏剧性时刻，可怕的秘密泄漏出来，接着便是某人的声誉扫地。当读者到小说最后几页了解到书中女主人公，那位一向待大家很好的可爱的老妇人年轻时一连毒死了她的5个丈夫时，不禁会毛骨悚然。
这种事发生在小说中是无可非议的。尽管我们人人都有各种大小秘密。连最亲密的朋友都不愿让他们知道， 但我们当中极少有人有柜中骷髅。我所认识的唯一的在柜中藏骷嵝的人便是乔治.卡尔顿，他甚至引以为自豪。乔治年轻时学过医，然而，他后来没当上医生，却成了一位成功的侦探小说作家。有一次，我在他家里度周末，过得很不愉快。这事我永远不会忘记。乔治把我领进客房，说这间很少使用。他让我打开行装后下楼吃饭。我将衬衫、内衣放进两个空抽屉里，然后我想把随身带来的两套西服中的一套挂到大衣柜里去。我打开柜门，站在柜门前一下惊呆了。一具骷髅悬挂在眼前，由于柜门突然打开，它也随之轻微摇晃起来，让我觉得它好像马上要跳出柜门朝我扑过来似的。我扔下西服冲下楼去告诉乔治。这是比“骇人听闻的秘密”更加惊人的东西，这是一具真正的骷髅啊！但乔治却无动于衷。“噢，是它呀！他笑着说道，俨然在谈论一位老朋友。“那是塞巴斯蒂安。你忘了我以前是学医的了。”
Lesson 25
The Cutty Sark
“卡蒂萨克”号帆船
Listen to the tape then answer the question below.
What piece of bad luck prevented the Cutty Sark from winning the race?
One of the most famous sailing ships of the nineteenth century, the Cutty Sark, can still be seen at Greewich. She stands on dry land and is visited by thousands of people each year. She serves as an impressive reminder of the great ships of past. Before they were replaced by steamships, sailing vessels like the Cutty Sark were used to carry tea from China and wool from Australia. The Cutty Sark was one the fastest sailing ships that has ever been built. The only other ship to match her was the Thermopylae. Both these ships set out from Shanghai on June 18th, 1872 on an exciting race to England. This race, which went on for exactly four exactly four months, was the last of its kind. It marked the end of the great tradition of ships with sails and the beginning of a new era.
The first of the two ships to reach Java after the race had begun was the Thermopylae, but on the Indian Ocean, the Cutty Sark took lead. It seemed certain that she would be the first ship home, but during the race she had a lot of bad luck. In August, she was struck by a very heavy storm during which her rudder was torn away. The Cutty Sark rolled from side to side and it became impossible to steer her. A temporary rudder was made on board from spare planks and it was fitted with great difficulty. This greatly reduced the speed of the ship, for there was a danger that if she traveled too quickly, this rudder would be torn away as well. Because of this, the Cutty Sark lost her lead. After crossing the Equator, the captain called in at a port to have a new rudder fitted, but by now the Thermopylae was over five hundred miles ahead. Though the new rudder was fitted at tremendous speed, it was impossible for the Cutty Sark to win. She arrived in England a week after the Thermopylae. Even this was remarkable, considering that she had had so many delays. These is no doubt that if she had not lost her rudder she would have won the race easily.
New words and expressions 生词和短语
impressive
steamship
n. 蒸汽轮船
vessel
n. 轮船，大木船
era
n. 时期，时代
Java
n. 爪哇（印度尼西亚一岛）
rudder
n. 舵
roll
v. 颠簸，摇摆
steer
v. 掌握方向
temporary
plank
n. 大块木板
fit
v. 安装
Equator
n. 赤道
delay
n. 耽误
人们在格林威治仍可看到19世纪最有名的帆船之一“卡蒂萨克”号。它停在陆地上，每年接待成千上万的参观者。它给人们留下深刻的印象，使人们回忆起历史上的巨型帆船，在蒸汽船取代帆船之前。“卡蒂萨克”号之类的帆船被用来从中国运回茶叶，从澳大利亚运回羊毛。“卡蒂萨克”号是帆船制造史上建造的最快的一艘帆船。唯一可以与之一比高低的是“塞姆皮雷”号帆船。两船于1872年6月18日同时从上海启航驶往英国，途中展开了一场激烈的比赛。这场比赛持续了整整4个月，是这类比赛中的最后一次，它标志着帆船伟大传统的结束与一个新纪元的开始。
比赛开始后，“赛姆皮雷”号率先抵达爪哇岛。但在印度洋上，“卡萨萨克”号驶到了前面。看来，它首先返抵英国是确信无疑的了，但它却在比赛中连遭厄运。8月份“卡蒂萨克”号遭到一场特大风暴的袭击，失去了一只舵。船身左右摇晃，无法操纵。船员用备用的木板在船上赶制了一只应急用的舵，并克服重重困难将舵安装就位，这样一来，大大降低了船的航速。因为船不能开得太快，否则就有危险，应急舵也会被刮走。因为这个缘故，“卡蒂萨克”号落到了后面。跨越赤道后，船长将船停靠在一个港口，在那儿换了一只舵。但此时，“赛姆皮雷”号早已在500多英里之遥了。尽管换装新舵时分秒必争，但“卡蒂萨克”号已经不可能取胜了，它抵达英国时比“塞姆皮雷”号晚了1个星期。但考虑到路上的多次耽搁，这个成绩也已很不容易了。毫无疑问，如果中途没有失去舵， “卡帝萨克”号肯定能在比赛中轻易夺冠。
Lesson 26
Wanted: a large biscuit tin
征购大饼干筒
Listen to the tape then answer the question below.
Listen who the prize for biggest biscuit?
No one can avoid being influenced by advertisements. Much as we may pride ourselves on our good taste, we are no longer free to choose the things we want, for advertising exerts a subtle influence on us. In their efforts to persuade us to buy this or that product, advertisers have made a close study of human nature and have classified all our little weaknesses.
Advertisers discovered years ago that all of us love to get something for nothing. An advertisement which begins with the magic word FREE can rarely go wrong. These days, advertisers not only offer free samples, but free cars, free houses, and free trips round the world as well. They devise hundreds of competitions which will enable us to win huge sums of money. Radio and television have made it possible for advertisers to capture the attention of millions of people in this way.
During a radio programme, a company of biscuit manufacturers once asked listeners to bake biscuits and send them to their factory. They offered to pay $10 a pound for the biggest biscuit baked by a listener. The response to this competition was tremendous. Before long, biscuits of all shapes and sizes began arriving at the factory. One lady brought in a biscuit on a wheelbarrow. It weighed nearly 500 pounds. A little later, a man came along with a biscuit which occupied the whole boot of his car. All the biscuits that were sent were carefully weighed. The largest was 713 pounds. It seemed certain that this would win the prize. But just before the competition closed, a lorry arrived at the factory with a truly colossal biscuit which weighed 2,400 pounds. It had been baked by a college student who had used over 1,000 pounds of flour, 800 pounds of sugar, 200 pounds of fat, and 400 pounds of various other ingredients. It was so heavy that a crane had to be used to remove it from the lorry. The manufacturers had to pay more money than they had anticipated, or they bought the biscuit from the student for$24,000.
New words and expressions 生词和短语
influence
v. 影响
pride
v. 骄傲
taste
n. 鉴赏力
exert
v. 施加
subtle
aj. 微妙的，难以捉摸的
n. 做广告的人
classify
v. 分类
magic
sample
n. 样品
devise
v. 设计，想出
capture
v. 吸引，赢得
manufacturer
n. 生产厂家，制造商
wheelbarrow
n. 独轮手推车
boot
n. （汽车尾部的）行李箱
ingredient
n. 配料
crane
n. 起重机
anticipate
v. 预期，预料
没有人能避免受广告的影响。尽管我们可以自夸自己的鉴赏力如何敏锐，但我们已经无法独立自主地选购自己所需的东西了。这是因为广告在我们身上施加着一种潜移默化的影响。做广告的人在力图劝说我们买下这种产品或那种产品之前，已经仔细地研究了人的本性，并把人的弱点进行了分类。
做广告的人们多年前就发现我们大家都喜欢免费得到东西。凡是用“免费”这个神奇的词开头的广告很少会失败的。目前，做广告的人不仅提供免费样品，而且还提供免费汽车，免费住房，免费周游世界。他们设计数以百计的竞赛，竞赛中有人可赢得巨额奖金。电台、电视使做广告的人可以用这种手段吸引成百万人的注意力。
有一次，在电台播放的节目里，一个生产饼干的公司请听众烘制饼干送到他们的工厂去。他们愿意以每磅10美元的价钱买下由听众烘制的最大的饼干。这次竞赛在听众中引起极其热烈的反响。不久，形状各异，大小不一的饼干陆续送到工厂。一位女士用手推车运来一个饼干，重达500磅左右。相隔不一会儿，一个男子也带来一个大饼干，那个饼干把汽车的行李箱挤得满满的。凡送来的饼干都仔细地称量。最重的一个达713磅，看来这个饼干获奖无疑了。但就在竞赛截止时间将到之际，一辆卡车驶进了工厂，运来了一个特大无比、重达2,400磅的饼干。它是由一个大学生烘制的，用去1,000多磅的面粉、800磅食糖、200磅动物脂肪及400磅其他各种原料。饼干份量太重了，用了一台起重机才把它从卡车上卸下。饼干公司不得不付出比他们预计多得多的钱，因为为买下那学生烘制的饼干他们支付了24,000美元。
Lesson 27
Nothing to sell
and nothing to buy
不卖也不买
Listen to the tape then answer the question below.
Listen to the tape then answer the question below.
What is the most important thing for a tramp?
It has been said that everyone lives by selling something. In the light of this statement, teachers live by selling knowledge, philosophers by selling wisdom and priests by selling spiritual comfort. Though it may be possible to measure the value of material good in terms of money, it is extremely difficult to estimate the true value of the services which people perform for us. There are times when we would willingly give everything we possess to save our lives, yet we might grudge paying a surgeon a high fee for offering us precisely this service. The conditions of society are such that skills have to be paid for in the same way that goods are paid for at a shop. Everyone has something to sell.
Tramps seem to be the only exception to this general rule. Beggars almost sell themselves as human being to arouse the pity of passers-by. But real tramps are not beggars. They have nothing to sell and require nothing from others. In seeking independence, they do not sacrifice their human dignity. A tramp may ask you for money, but he will never ask you to feel sorry for him. He has deliberately chosen to lead the life he leads and is fully aware of the consequences. He may never be sure where the next meal is coming from, but his is free from the thousands of anxieties which afflict other people. His few material possessions make it possible for him to move from place to place with ease. By having to sleep in the open, he gets far closer to the world of nature than most of us ever do. He may hunt, beg, or stead occasionally to keep himself alive; he may even, in times of real need, do a little work; but he will never sacrifice his freedom. We often speak of my even, in times of real need, do a little work; but he will never sacrifice his freedom. We often speak of tramps with contempt and put them in the same class as beggars, but how many of us can honestly say that we have not felt a little envious of their simple way of life and their freedom from care?
New words and expressions 生词和短语
philosopher
n. 哲学家
wisdom
n. 智慧
priest
n. 牧师
spiritual
grudge
v. 不愿给，舍不得给
surgeon
n. 外科大夫
passer-by
n. 过路人（复数 passers-by)
dignity
n. 尊严
deliberately
consequence
n. 后果，结果
afflict
v. 使苦恼，折磨
ease
n. 容易
nature
n. 大自然
contempt
n. 蔑视的
envious
据说每个人都靠出售某种东西来维持生活。根据这种说法，教师靠卖知识为生，哲学家靠卖智慧为生，牧师靠卖精神安慰为生。虽然物质产品的价值可以用金钱来衡量，但要估算别人为我们为所提供的服务的价值却是极其困难的。有时，我们为了挽救生命，愿意付出我们所占有的一切。但就在外科大夫给我们提供了这种服务后，我们却可能为所支付的昂贵的费用而抱怨。社会上的情况就是如此，技术是必须付钱去买的，就像在商店里要花钱买商品一样。人人都有东西可以出售。
在这条普遍的规律前面，好像只有流浪汉是个例外，乞丐出售的几乎是他本人，以引起过路人的怜悯。但真正的流浪并不是乞丐。他们既不出售任何东西，也不需要从别人那儿得到任何东西，在追求独立自由的同时，他们并不牺牲为人的尊严。游浪汉可能会向你讨钱，但他从来不要你可怜他。他是故意在选择过那种生活的，并完全清楚以这种方式生活的后果。他可能从不知道下顿饭有无着落，但他不像有人那样被千万桩愁事所折磨。他几乎没有什么财产，这使他能够轻松自如地在各地奔波。由于被迫在露天睡觉，他比我们中许多人都离大自然近得多。为了生存，他可能会去打猎、乞讨，偶尔偷上一两回；确实需要的时候，他甚至可能干一点儿活，但他决不会牺牲自由。说起流浪汉，我们常常带有轻蔑并把他们与乞丐归为一类。但是，我们中有多少人能够坦率地说我们对流浪汉的简朴生活与无忧无虑的境况不感到有些羡慕呢？
Lesson 28
Five pound too dear
五磅也太贵
Listen to the tape then answer the question below.
Why was even five pounds 'too dear'?
Small boats loaded with wares sped to the great liner as she was entering the harbour. Before she had anchored, the men from the boats had climbed on board and the decks were son covered with colourful rugs from Persia, silks from India, copper coffee pots, and beautiful handmade silverware. It was difficult not to be tempted. Many of the tourists on board had begun bargaining with the tradesmen, but I decide not to buy anything until I had disembarked.
I had no sooner got off the ship than I was assailed by a man who wanted to sell me a diamond ring. I had no intention of buying one, but I could not conceal the fact that I was impressed by the size of the diamonds. Some of them were as big as marbles. The man went to great lengths to prove that the diamonds were real. As we were walking past a shop, he held a diamond firmly against the window and made a deep impression in the glass. It took me over half an hour to get rid of him.
The next man to approach me was selling expensive pens and watches. I examined one of the pens closely. It certainly looked genuine. At the base of the gold cap, the words 'made in the U.S.A' had been nearly inscribed. The man said that the pen was worth $50, but as a special favour, he would let me have it for$30. I shook my head and held up five fingers indicating that I was willing to pay $5. Gesticulating wildly, the man acted as if he found my offer outrageous, but he eventually reduced the price to$10. Shrugging my shoulders, I began to walk away when, a moment later, he ran after me and thrust the pen into my hands. Though he kept throwing up his arms in despair, he readily accepted the $5 I have him. I felt especially pleased with my wonderful bargain -- until I got back to the ship. No matter how hard I tried, it was impossible to fill this beautiful pen with ink and to this day it has never written a single world! New words and expressions 生词和短语 wares n. 货物，商品 anchor v. 停航下锚 deck n. 甲板 silverware n. 银器 tempt v. 吸引；引诱 bargain v. 讨价还价 disembark v. 下船上岸 assail v. 纠缠 marble n. 小玻璃球 inscribe v. 刻写，雕 favour n. 好处，优惠 gesticulate v. （讲话时）打手势 outrageous adj. 出人预料的；令人不悦的 thrust v. 硬塞给 参考译文 当一艘大型班船进港的时候，许多小船载着各种杂货快速向客轮驶来。大船还未下锚。小船上的人就纷纷爬上客轮。一会儿工夫，甲板上就摆满了色彩斑斓的波斯地毯。印度丝绸。铜咖啡壶以及手工制作的漂亮的银器。要想不为这些东西所动心是很困难的。船上许多游客开始同商贩讨价还价起来，但我打定主意上岸之前什么也不买。 我刚下船，就被一个人截住，他向我兜售一枚钻石戒指。我根本不想买，但我不能掩饰这样一个事实：其钻石之大给我留下了深刻的印象。有的钻石像玻璃球那么大。那人竭力想证明那钻石是真货。我们路过一家商店时，他将一颗钻石使劲地往橱窗上一按，在玻璃上留下一道深痕。我花了半个多小时才摆脱了他的纠缠。 向我兜售的第二个人是卖名贵钢笔和手表的。我仔细察看了一枝钢笔，那看上去确实不假，金笔帽下方整齐地刻有“美国制造”字样。那人说那支笔值50英镑，作为特别优惠，他愿意让我出30英镑成交。我摇摇头，伸出5根手指表示我只愿出5镑钱。那人激动地打着手势，仿佛我的出价使他不能容忍。但他终于把价钱降到了10英镑。我耸耸肩膀掉头走开了。一会儿，他突然从后追了上来，把笔塞到我手里。虽然他绝望地举起双手，但他毫不迟疑地收下了我付给他的5镑钱。在回到船上之前，我一直为我的绝妙的讨价还价而洋洋得意。然而不管我如何摆弄，那枝漂亮的钢笔就是吸不进墨水来。直到今天，那枝笔连一个字也没写过！ Lesson 29 Funny or not? 是否可笑？ Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What is the basis of 'sick' humour? Whether we find a joke funny or not largely depends on were we have been brought up. The sense of humour is mysteriously bound up with national characteristics. A Frenchman, for instance, might find it hard to laugh at a Russian joke. In the same way, a Russian might fail to see anything amusing in a joke witch would make an Englishman laugh to tears. Most funny stories are based on comic situations. In spite of national differences, certain funny situations have a universal appeal. No matter where you live, you would find it difficult not to laugh at, say, Charlie Chaplin's early films. However, a new type of humour, which stems largely from the U.S., has recently come into fashion. It is called 'sick humour'. Comedians base their jokes on tragic situation like violent death or serious accidents. Many people find this sort of joke distasteful The following example of 'sick humour' will enable you to judge for yourself. A man who had broken his right leg was taken to hospital a few weeks before Christmas. From the moment he arrived there, he kept on pestering his doctor to tell him when he would be able to go home. He dreaded having to spend Christmas in hospital. Though the doctors did his best, the patient's recovery was slow. On Christmas Day, the man still had his right leg in plaster. He spent a miserable day in bed thinking of all the fun he was missing. The following day, however, the doctor consoled him by telling him that his chances of being able to leave hospital in time for New Year celebrations were good. The good. The man took heart and, sure enough, on New Years' Eve he was able to hobble along to a party. To compensate for his unpleasant experiences in hospital, the man drank a little more than was good for him. In the process, he enjoyed himself thoroughly and kept telling everybody how much he hated hospitals. He was still mumbling something about hospitals at the end of the party when he slipped on a piece of ice and broke his left leg. New words and expressions 生词和短语 largely adv. 在很大程度上 comic adj. 喜剧的，可笑的 universal adj. 普通的 comedian n. 滑稽演员，喜剧演员 distasteful adj. 讨厌的 pester v. 一再要求，纠缠 dread v. 惧怕 recovery n. 康复 plaster n. 熟石膏 console v. 安慰，慰问 hobble v. 瘸着腿走 compensate v. 补偿 mumble v. 喃喃而语 参考译文 我们觉得一则笑话是否好笑，很大程度取决于我们是在哪儿长大的。幽默感与民族有着神秘莫测的联系。譬如，法国人听完一则俄国笑话可能很难发笑。同样的道理，一则可以令英国人笑出泪来的笑话，俄国人听了可能觉得没有什么可笑之处。 大部分令人发笑的故事都是根据喜剧情节编写的。尽管民族不同，有些滑稽的情节却能产生普遍的效果。比如说，不管你生活在哪里，你看查理.卓别林的早期电影很难不发笑。然而，近来一种新式幽默流行了起来，这种幽默主要来自美国。它被叫作“病态幽默”。喜剧演员根据悲剧情节诸如暴死，重大事故等来编造笑话。许多人认为这种笑话是低级庸俗的。下面是个“病态幽默”的实例，你可据此自己作出判断。 圣诞节前几周，某人摔断了右腿被送进医院。从他进医院那一刻时，他就缠住医生，让医生告诉他什么时候能回家。他十分害怕在医院过圣诞。尽管医生竭力医治，但病人恢复缓慢。圣诞节那天，他的右腿还上着石膏，他在床上郁郁不乐地躺了一天，想着他错过的种种欢乐。然而，第二天，医生安慰他说，出院欢度新年的可能性还是很大的，那人听后振作了精神。果然，除夕时他可以一瘸一拐地去参加晚会了。为了补偿住院这一段不愉快的经历，那人喝得稍许多了一点。在晚会上他尽情娱乐，一再告诉大家他是多么讨厌医院。晚会结束时，他嘴里还在嘟哝着医院的事，突然踩到一块冰上滑倒了，摔断了左腿。 Lesson 30 The death of a ghost 幽灵之死 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Why did the two brothers keep the secret? For years, villagers believed that Endley Farm was hunted. The farm was owned by two brothers, Joe and Bob Cox. They employed a few farmhands, but no one was willing to work there long. Every time a worker gave up his job, he told the same story. Farm labourers said that they always woke up to find that work had been done overnight. Hay had been cut and cowsheds had been cleaned. A farm worker, who stayed up all night claimed to have seen a figure cutting corn in the moonlight. In time, it became an accepted fact the Cox brothers employed a conscientious ghost that did most of their work for them. No one suspected that there might be someone else on the farm who had never been seen. This was indeed the case. A short time ago, villagers were astonished to learn that the ghost of Endley had died. Everyone went to the funeral, for the 'ghost' was none other than Eric Cox, a third brother who was supposed to have died as a young man. After the funeral, Joe and Bob revealed a secret which they had kept for over fifty years. Eric had been the eldest son of the family, very much older than his two brothers. He had been obliged to join the army during the Second World War. As he hated army life, he decided to desert his regiment. When he learnt that he would be sent abroad, he returned to the farm and his father hid him until the end of the war. Fearing the authorities, Eric remained in hiding after the war as well. His father told everybody that Eric had been killed in action. The only other people who knew the secret were Joe and Bob. They did not even tell their wives. When their father died, they thought it their duty to keep Eric in hiding. All these years, Eric had lived as a recluse. He used to sleep during the day and work at night, quite unaware of the fact that he had become the ghost of Endley. When he died, however, his brothers found it impossible to keep the secret any longer. New words and expressions 生词和短语 labourer n. 劳动者 overnight adv. 一夜期间 hay n. 干草 corn n. 谷物 moonlight n. 月光 conscientious adj. 认真的 suspect v. 怀疑 desert v. （军队中）开小差 regiment n. （军队）团 action n. 战斗 recluse n. 隐士 参考译文 多年来，村民们一直认为恩得利农场在闹鬼。恩得利农场属于乔.考科斯和鲍勃.考科斯兄弟俩所有。他们雇了几个农工，但谁也不愿意在那儿长期工作下去。每次雇工辞职后都叙述着同样的故事。雇工们说，常常一早起来发现有人在夜里把活干了，干草已切好，牛棚也打扫干净了。有一个彻夜未眠的雇工还声称他看见一个人影在月光下收割庄稼。随着时间的流逝，考科斯兄弟雇了一个尽心尽责的鬼，他们家的活大部分都让鬼给干了，这件事成了公认的事实。 谁也没想到农场竟会有一个从未露面的人。但事实上确有此人。不久之前，村民们惊悉恩得利农场的鬼死了。大家都去参加了葬礼，因为那“鬼”不是别人，正是农场主的兄弟埃里克.考科斯。人们以为埃里克年轻时就死了。葬礼之后，乔和鲍勃透露了他们保守了长达50多年的秘密。 埃里克是这家长子。年龄比他两个弟弟大很多，第二次世界大战期间被迫参军。他讨厌军旅生活，决定逃离所在部队。当他了解自己将被派遣出国时，他逃回农场，父亲把他藏了起来，直到战争结束。由于害怕当局，埃里克战后继续深藏不露。他的父亲告诉大家，埃里克在战争中被打死了。除此之外，只有乔与鲍知道这个秘密。但他俩连自己的妻子都没告诉。父亲死后，他们兄弟俩认为有责任继续把埃里克藏起来。这些年来，埃里克过着隐士生活，白天睡觉，夜里出来干活，一点不知道自己已成了恩得利家场的活鬼。他死后，他的弟弟们才觉得无法再保守这个秘密了。 Lesson 31 A lovable eccentric 可爱的怪人 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Why did the shop assistant refuse to serve Dickie? True eccentrics never deliberately set out to draw attention to themselves. They disregard social conventions without being conscious that they are doing anything extraordinary. This invariably wins them the love and respect of others, for they add colour to the dull routine of everyday life. Up to the time of his death, Richard Colson was one of the most notable figures in our town. He was a shrewd and wealthy businessman, but most people in the town hardly knew anything about this side of his life. He was known to us all as Dickie and his eccentricity had become legendary long before he died. Dickie disliked snobs intensely. Though he owned a large car, he hardly ever used it, preferring always to go on foot. Even when it was raining heavily, he refused to carry an umbrella. One day, he walked into an expensive shop after having been caught in a particularly heavy shower. He wanted to buy a$300 watch for his wife, but he was in such a bedraggled condition than an assistant refused to serve him. Dickie left the shop without a word and returned carrying a large cloth bag. As it was extremely heavy, he dumped it on the counter. The assistant asked him to leave, but Dickie paid no attention to him and requested to see the manager. Recognizing who the customer was, the manager was most apologetic and reprimanded the assistant severely. When Dickie was given the watch, the presented the assistant with the cloth bag. It contained $300 in pennies. He insisted on the assistant's counting the money before he left -- 30,000 pennies in all! On another occasion, he invited a number of important critics to see his private collection of modern paintings. This exhibition received a great deal of attention in the press, for though the pictures were supposed to be the work of famous artists, they had in fact been painted by Dickie. It took him four years to stage this elaborate joke simply to prove that critics do not always know what they are talking about. New words and expressions 生词和短语 lovable adj. 可爱的 eccentric n. （行为）古怪人 disregard v. 不顾，漠视 convention n. 习俗，风俗 conscious adj. 感觉到的，意识到的 invariably adv. 总是，经常地 routine n. 常规；惯例 shrewd adj. 精明的 eccentricity n. 怪僻 legendary adj. 传奇般的 snob n. 势利小人，谄上欺下的人 intensely adv. 强烈地 bedraggled adj. 拖泥带水的 dump v. 把……砰的一声抛下 apologetic adj. 道歉的 reprimand v. 训斥 stage v. 暗中策划 elaborate adj. 精心构思的 参考译文 真正古怪的人从不有意引人注意。他们不顾社会习俗，意识不到自己所作所为有什么特殊之处。他们总能赢得别人的喜爱与尊敬，因为他们给平淡单一的日常生活增添了色彩。 理查德.科尔森生前是我们镇上最有名望的人之一。他是个精明能干、有钱的商人，但镇上大部分人对他生活中的这一个方面几乎一无所知。大家都管他叫迪基。早在他去世前很久，他的古怪行为就成了传奇故事了。 迪基痛恨势利小人。尽管他有一辆豪华小轿车，但却很少使用，常常喜欢以步代车。即使大雨倾盆，他也总是拒绝带伞。一天，他遇上一场瓢泼大雨，淋得透湿。他走进一家高级商店，要为妻子买一块价值300英镑的手表。但店员见他浑身泥水的样子，竟不肯接待他。迪基二话没说就走了。一会儿，他带着一个大布口袋回到店里。布袋很沉，他重重地把布袋扔在柜台上。店员让迪基走开，他置之不理，并要求见经理。经理认出了这位顾客，表示了深深的歉意，还严厉地训斥了店员。店员为迪基拿出了那块手表，迪基把布口袋递给他，口袋里面装着300镑的便士。他坚持要店员点清那些硬币后他才离去。这些硬币加在一起共有30,000枚！ 还有一次，他邀请一些著名评论家来参观他私人收藏的现代画。这次展览引起报界广泛注意，因为这些画名义上是名家的作品，事实上是迪基自己画的。他花了4年时间策划这出精心设计的闹剧，只是想证明评论家们有时并不解他们所谈论的事情。 Lesson 32 A lost ship 一艘沉船 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Did the crew of the Elkor find what they were looking for? Why? The salvage operation had been a complete failure. The small ship, Elkor, which had been searching the Barents Sea for weeks, was on its way home. A radio message from the mainland had been received by the ship's captain instructing him to give up the search. The captain knew that another attempt would be made later, for the sunken ship he was trying to find had been carrying a precious cargo of gold bullion. Despite the message, the captain of the Elkor decided to try once more. The sea bed was scoured with powerful nets and there was tremendous excitement on board went a chest was raised from the bottom. Though the crew were at first under the impression that the lost ship had been found, the contents of the chest proved them wrong. What they had in fact found was a ship which had been sunk many years before. The chest contained the personal belongings of a seaman, Alan Fielding. There were books, clothing and photographs, together with letters which the seaman had once received from his wife. The captain of the Elkor ordered his men to salvage as much as possible from the wreck. Nothing of value was found, but the numerous items which were brought to the surface proved to be of great interest. From a heavy gun that was raised, the captain realized that the ship must have been a cruiser. In another chest, which contained the belongings of a ship's officer, there was an unfinished letter which had been written on March 14th, 1943. The captain learnt from the letter that the name of the lost ship was the Karen. The most valuable find of all was the ship's log book, parts of which it was still possible to read. From this the captain was able to piece together all the information that had come to light. The Karen had been sailing in a convoy to Russia when she was torpedoed by an enemy submarine. This was later confirmed by naval official at the Ministry of Defiance after the Elkor had returned home. All the items that were found were sent to the War Museum. New words and expressions 生词和短语 salvage v. 救助，营救；打捞 Barents n. 巴伦支（海） sunken adj. 沉没的 cargo n. 货物 bullion n. 金条；银条 scour v. 彻底搜索 chest n. 大箱子 contents n. （复数）所装的东西 belongings n. （复数）所有物 item n. 物件 cruiser n. 巡洋舰 find n. 找到的物品 log book 航海日志 piece v. 拼成整体 convoy n. 护航 torpedo v. 用鱼雷攻击 submarine n. 潜水艇 naval adj. 海军的 ministry n. （政府的）部 参考译文 打捞工作彻底失败了。小船“埃尔科”号在巴伦支海搜寻了几个星期之后，正在返航途中。返航前，该船船长收到了大陆发来的电报，指示他们放弃这次搜寻。船长知道日后还会再作尝试，因为他试图寻找的沉船上载有一批珍贵的金条。 尽管船长接了电报，他还是决定再试一试。他们用结实的网把海床搜索了一遍。当一只箱子从海底被打捞上来时，甲板上人们激动不已。船员们开始认为沉船找着了，但海底沉箱内的物品证明他们弄错了。事实上，他们发现的是另一艘沉没多年的船。 木箱内装有水手艾伦.菲尔丁的私人财物，其中有书箱、衣服、照片以及水手收到的妻子的来信。“埃尔科”号船长命令船员们尽量从沉船中打捞物品，但没发现什么值钱的东西，不过打捞出来的众多的物品还是引起了大家极大的兴趣。从捞起的一门大炮来看，船长认为那艘船一定是艘巡洋舰。另一只海底沉箱中装的是船上一位军官的财物，其中有一封写于1943年3月14日的信，但没有写完。从这封信中船长了解到沉船船名是“卡伦”号。打捞到的东西中最有价值的是船上的航海日志，其中有一部分仍然清晰可读。据此，船长可以将所有的那些已经搞清的材料拼凑起来。“卡伦”号当年在为其他船只护航驶往俄国的途中突然遭到敌方潜水艇鱼雷的袭击。这一说法在“埃尔科”号返航后得到的国防部一位海军官员的证实。那次打捞到的所有物品均被送往军事博物馆。 Lesson 33 A day t remember 难忘的一天 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What incident began the series of traffic accidents? We have all experienced days when everything goes wrong. A day may begin well enough, but suddenly everything seems to get out of control. What invariably happens is that a great number of things choose to go wrong at precisely the same moment. It is as if a single unimportant event set up a chain of reactions. Let us suppose that you are preparing a meal and keeping an eye on the baby at the same time. The telephone rings and this marks the prelude to an unforeseen series of catastrophes. While you are on the phone, the baby pulls the tablecloth off the table, smashing half your best crockery and cutting himself in the process. You hang up hurriedly and attend to baby, crockery, etc. Meanwhile, the meal gets burnt. As if this were not enough to reduce you to tears, your husband arrives, unexpectedly bringing three guests to dinner. Things can go wrong on a big scale, as a number of people recently discovered in Parramatta, a suburb of Sydney. During the rush hour one evening two cars collided and both drivers began to argue. The woman immediately behind the two cars happened to be a learner. She suddenly got into a panic and stopped her car. This made the driver following her brake hard. His wife was sitting beside him holding a large cake. As she was thrown forward, the cake went right through the windscreen and landed on the road. Seeing a cake flying through the air, a lorry driver who was drawing up alongside the car, pulled up all of a sudden. The lorry was loaded with empty beer bottles and hundreds of them slid off the back of the vehicle and on to the road. This led to yet another angry argument. Meanwhile, the traffic piled up behind. It took the police nearly an hour to get the traffic on the move again. In the meantime, the lorry driver had to sweep up hundreds of broken bottles. Only two stray dogs benefited from all this confusion, for they greedily devoured what was left of the cake. It was just one of those days! New words and expressions 生词和短语 prelude n. 序幕，前奏 unforeseen adj. 意料之外的 series n. 系列 catastrophe n. 大祸，灾难 crockery n. 陶器，瓦器 suburb n. 郊区 collide v. 猛撞 learner n. 初学者 panic n. 惊慌，恐慌 windscreen n. （汽车的）挡风玻璃 alongside prep.在……的旁边，与……并排 slide (slid, slid) v. 滑 stray adj. 迷失的，离群的 confusion n. 混乱 greedily adv. 贪婪地 devour v. 狼吞虎咽地吃 参考译文 我们大家都有过事事不顺心的日子。一天开始时，可能还不错，但突然间似乎一切都失去了控制。情况经常是这样的，许许多多的事情都偏偏赶在同一时刻出问题，好像是一件无关紧要的小事引起了一连串的连锁反应。假设你在做饭，同时又在照看孩子。这时电话铃响了。它预示着一连串意想不到的灾难的来临。就在你接电话时，孩子把桌布从桌子上扯下来，将家中最好的陶瓷餐具半数摔碎，同时也弄伤了他自己。你急急忙忙挂上电话，赶去照看孩子和餐具。这时，饭又烧糊了。好像这一切还不足以使你急得掉泪，你的丈夫接着回来了，事先没打招呼就带来3个客人吃饭。 就像许多人最近在悉尼郊区帕拉马塔发现的那样，有时乱子会闹得很大。一天傍晚交通最拥挤时，一辆汽车撞上前面一辆汽车，两个司机争吵起来。紧跟其后的一辆车上的司机碰巧是个初学者，她一惊之下突然把车停了下来。她这一停使得跟在后头的司机也来个急刹车。司机妻子正坐在他身边，手里托着块大蛋糕。她往前一冲，蛋糕从挡风玻璃飞了出去掉到马路上。此时，一辆卡车正好从后边开到那辆汽车边上，司机看见一块蛋糕从天而降，紧急刹车。卡车上装着空啤酒瓶。成百只瓶子顺势从卡车后面滑出车外落在马路上。这又引起一场唇枪舌剑的争吵。与此同时，后面的车辆排成了长龙，警察花了将近一个小时才使车辆又开起来。在这段时间里，卡车司机不得不清扫那几百只破瓶子。只有两只野狗从这一片混乱中得到好处，它们贪婪地吃掉了剩下的蛋糕。这就是事事不顺心的那么一天！ Lesson 34 A happy discovery 幸运的发现 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What was the 'happy discovery'? Antique shops exert a peculiar fascination on a great many people. The more expensive kind of antique shop where rare objects are beautifully displayed in glass cases to keep them free from dust is usually a forbidding place. But no one has to muster up courage to enter a less pretentious antique shop. There is always hope that in its labyrinth of musty, dark, disordered rooms a real rarity will be found amongst the piles of assorted junk that little the floors. No one discovers a rarity by chance. A truly dedicated bargain hunter must have patience, and above all, the ability to recognize the worth of something when he sees it. To do this, he must be at least as knowledgeable as the dealer. Like a scientist bent on making a discovery, he must cherish the hope that one day he will be amply rewarded. My old friend, Frank Halliday, is just such a person. He has often described to me how he picked up a masterpiece for a mere$50. One Saturday morning, Frank visited an antique shop in my neighbourhood. As he had never been there before, he found a great deal to interest him. The morning passed rapidly and Frank was about to leave when he noticed a large packing case lying on the floor. The morning passed rapidly and Frank just come in, but that he could not be bothered to open it. Frank begged him to do so and the dealer reluctantly prised it open. The contents were disappointing. Apart from an interesting-looking carved dagger, the box was full of crockery, much of it broken. Frank gently lifted the crockery out of the box an suddenly noticed a miniature painting at the bottom of the packing case. As its composition and line reminded him of an Italian painting he knew well, he decided to buy it. Glancing at it briefly, the dealer told him that it was worth $50. Frank could hardly conceal his excitement, for he knew that he had made a real discovery. The tiny painting proved to be an unknown masterpiece by Correggio and was worth hundreds of thousands of pounds. New words and expressions 生词和短语 antique n. 古董，古玩 fascination n. 魅力，迷惑力 forbidding adj. 望而生畏的，望而却步的 muster v. 鼓起 pretentious adj. 自命不凡的，矫饰的 labyrinth n. 迷宫 musty adj. 陈腐的，发霉的 rarity n. 稀世珍品 assorted adj. 各式各样的 junk n. 破烂货，废品 litter v. 杂乱地布满 dedicated adj. 专心致志的 bargain hunter 到处找便宜货买的人 dealer v. 商人 cherish v. 期望，渴望 amply adv. 足够地 masterpiece n. 杰作 mere adj. 仅仅的 prise v. 撬开 carve v. 镌刻 dagger n. 短剑，匕首 miniature adj. 小巧的，小型的 composition n. 构图 参考译文 古玩店对许多人来说有一种特殊的魅力。高档一点的古玩店为了防尘，把文物漂亮地陈列在玻璃柜子里，那里往往令人望而却步。而对不太装腔作势的古玩店，无论是谁都不用壮着胆子才敢往里进。人们还常常有希望在发霉、阴暗、杂乱无章、迷宫般的店堂里，从杂乱地摆放在地面上的、一堆堆各式各样的破烂货里找到一件稀世珍品。 无论是谁都不会一下子就发现一件珍品。一个到处找便宜的人必须具有耐心，而且最重要的是看到珍品时要有鉴别珍品的能力。要做到这一点，他至少要像古董商一样懂行。他必须像一个专心致志进行探索的科学家那样抱有这样的希望，即终有一天，他的努力会取得丰硕的成果。 我的老朋友弗兰克.哈利戴正是这样一个人。他多次向我详细讲他如何只花50英镑便买到一位名家的杰作。一个星期六的上午，弗兰克去了我家附近的一家古玩店。由于他从未去过那儿，结果他发现许多有趣的东西。上午很快过去了，弗兰克正准备离去，突然看见地板上放着一只体积很大的货箱。古董商告诉他那只货箱刚到不久，但他嫌麻烦不想把它打开。经弗兰克恳求，古董商才勉强把货箱撬开了。箱内东西令人失望。除了一柄式样别致、雕有花纹的匕首外，货箱内装满陶器，而且大部分都已破碎裂。弗兰克轻轻地把陶器拿出箱子，突然发现在箱底有一幅微型画，画面构图与纸条使他想起一幅他所熟悉的意大利画，于是他决定将画买了下来。古董商漫不经心看了一眼那幅画，告诉弗兰克那画值50英镑。弗兰克几乎无法掩饰自己兴奋的心情，因为他明白自己发现了一件珍品。那幅不大的画原来是柯勒乔的一幅未被发现的杰作，价值几十万英镑。 Lesson 35 Justice was done 伸张正义 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 The word 'justice' is given two different meanings in the text. What is the distinction between them? The word justice is usually associated with courts of law. We might say that justice has been done when a man's innocence or guilt has been proved beyond doubt. Justice is part of the complex machinery of the law. Those who seek it undertake an arduous journey and can never be sure that they will find it. Judges, however wise or eminent, are human and can make mistakes. There are rare instances when justice almost ceases to be an abstract concept. Reward or punishment are meted out quite independent of human interference. At such times, justice acts like a living force. When we use a phrase like 'it serves him right', we are, in part, admitting that a certain set of circumstances has enabled justice to act of its own accord. When a thief was caught on the premises of large jewellery store on morning, the shop assistants must have found it impossible to resist the temptation to say 'it serves him right.' The shop was an old converted house with many large, disused fireplaces and tall, narrow chimneys. Towards midday, a girl heard a muffed cry coming from behind on of the walls. As the cry was repeated several times, she ran to tell the manager who promptly rang up the fire brigade. The cry had certainly come form one of the chimneys, but as there were so many of them, the fire fighters could not be certain which one it was. They located the right chimney by tapping at the walls and listening for the man's cries. After chipping through a wall which was eighteen inches thick, they found that a man had been trapped in the chimney. As it was extremely narrow, the man was unable to move, but the fire fighters were eventually able to free him by cutting a huge hole in the wall. The sorry-looking, blackened figure that emerged, admitted at once that he had tried to break into the shop during the night but had got stuck in the chimney. He had been there for nearly ten hours. Justice had been done even before the man was handed over to the police. New words and expressions 生词和短语 justice n. 正义，公正；司法 court n. 法院 law n. 法律 innocence n. 无辜 undertake v. 承担；着手做 arduous adj. 艰苦的，艰难的 abstract adj. 抽象的 concept n. 概念，观念 mete out 给予，处置 interference n. 干涉 accord n. 一致 premises n. 房屋 convert v. 转变，改变 disused adj. 不再用的，废弃的 fireplace n. 壁炉 muffle v. 捂住，厌抑 chip v. 砍，削，凿 blacken v. 使变黑 emerge v. （从某处）出现 参考译文 “正义”这个词常常是同法庭连在一起的。当某人被证据确凿地证明无罪的时候，我们也许会说正义得到了伸张。正义是复杂的法律机器组成部分。那些寻求正义的人走的是一条崎岖的道路，从来没有把握他们最终将到正义。法官无论如何聪明与有名，毕竟也是人，也会出差错的。 在个别情况下，正义不再是一种抽象概念。奖惩的实施是不受人意志支配的。在这种时候，正义像一种有生命的力量行使其职能。当我们说“他罪有应得”这句话的时候，我们部分承认了某种特定的环境使得正义自动地起了作用。 一天上午，当一个小偷在一家大型珠宝店里被人抓住的时候，店员一定会忍不住说：“他罪有应得。”那是一座老式的、经过改造的房子，店里有许多废置不用的大壁炉和又高又窄的烟囱。快到中午的时候，一个女售货员听见从一堵墙里传出一种闷声闷气的叫声。由于这种喊叫声重复了几次，她跑去报告经理，经理当即给消防队挂了电话。喊叫声肯定是从烟囱里传出来的，然而，因为烟囱太多，消防队员无法确定到底是哪一个。他们通过叫击烟囱倾叫声而确定传出声音的那个烟囱。他们凿透了18英寸厚的墙壁，发现有个人卡在烟囱里。由于烟囱太窄，那人无法动弹。消防队员在墙上挖了个大洞，才终于把他解救出来。那个看来满脸沮丧、浑身漆黑的家伙从烟囱里一出来，就承认头天夜里他企图到店里行窍，但让烟囱卡住了。他已经在烟囱里被困了将近10个小时。甚至在那人还没被送交给警察之前，正义就已得到了伸张。 Lesson 36 A chance in a million 百万分之一的机遇 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What was the chance in a million? We are less credulous than we used to be. In the nineteenth century, a novelist would bring his story to a conclusion by presenting his readers with a series of coincidences -- most of them wildly improbable. Readers happily accepted the fact that an obscure maidservant was really the hero's mother. A long-lost brother, who was presumed dead, was really alive all the time and wickedly plotting to bring about the hero's downfall. And so on. Modern readers would find such naive solution totally unacceptable. Yet, in real life, circumstances do sometimes conspire to bring about coincidences which anyone but a nineteenth century novelist would find incredible. When I was a boy, my grandfather told me how a German taxi driver, Franz Bussman, found a brother who was thought to have been killed twenty years before. While on a walking tour with his wife, he stooped to talk to a workman. After they had gone on, Mrs. Bussman commented on the workman's close resemblance to her husband and even suggested that he might be his brother. Franz poured scorn on the idea, pointing out that his brother had been killed in action during the war. Though Mrs. Busssman fully acquainted with this story, she thought that there was a chance in a million that she might be right. A few days later, she sent a boy to the workman to ask him if his name was Hans Bussman. Needless to say, the man's name was Hans Bussman and he really was Franz's long-lost brother. When the brothers were reunited, Hans explained how it was that he was still alive. After having been wounded towards the end of the war, he had been sent to hospital and was separated from his unit. The hospital had been bombed and Hans had made his way back into Western Germany on foot. Meanwhile, his unit was lost and all records of him had been destroyed. Hans returned to his family home, but the house had been bombed and no one in the neighbourhood knew what had become of the inhabitants. Assuming that his family had been killed during an air raid, Hans settled down in a village fifty miles away where he had remained ever since. New words and expressions 生词和短语 credulous adj. 轻信的 improbable adj. 不大可能的 obscure adj. 不起眼的 maidservant n. 女仆，女佣 presume v. 假定 wickedly adv. 心眼坏地，居心叵测地 plot v. 密谋 downfall n. 倒台，垮台 naive adj. 天真的 unacceptable adj. 不能接受的 conspire v. （事件）巧合促成 incredible adj. 难以置信的 scorn n. 嘲弄，挖苦 acquaint v. 使了解 reunite v. 使团聚 assume v. 假定，认为 参考译文 我们不再像以往那样轻易相信别人了。在19世纪，小说家常在小说结尾处给读者准备一系列的巧合——大部分是牵强附会，极不可能的。当时的读者却愉快地接受这样一些事实，一个低贱的女佣实际上是主人公的母亲；主人公一位长期失散的兄弟，大家都以为死了，实际上一直活着，并且正在策划暗算主人公；如此等等，现代读者会觉得这种天真的结局完全无法接受。不过，在现实生活中，有时确实会出现一些巧合，这些巧合除了19世纪小说家外谁也不会相信。 当我是个孩子的时候，我祖父给我讲了一位德国出租汽车司机弗朗兹。巴斯曼如何找到了据信已在20年前死去的兄弟的事。一次，他与妻子徒步旅行。途中，停下来与一个工人交谈，接着他们继续往前走去。巴斯曼夫人说那工人与她丈夫相貌很像，甚至猜测他可能就是她丈夫的兄弟。弗朗兹对此不屑一顾，指出他兄弟已经在战争中阵亡了。尽管巴斯曼夫人熟知这个情况，但她仍然认为自己的想法仍有百万分之一的可能性。几天后，她派了一个男孩去问那人是否叫汉斯.巴斯曼。不出巴斯曼夫人所料，那人的名字真是汉斯.巴斯曼，他确实是弗朗兹失散多年的兄弟。兄弟俩团聚之时，汉斯说明了他活下来的经过，战争即将结束时，他负伤被送进医院，并与部队失去联系。医院遭到轰炸，汉斯步行回到了西德。与此同时，他所在部队被击溃，他的所有档案材料全部毁于战火。汉斯重返故里，但他的家已被炸毁，左邻右舍谁也不知原住户的下落，汉斯以为全家人都在空袭中遇难，于是便在距此50英里外的一座村子里定居下来，直至当日。 Lesson 37 The Westhaven Express 开往威斯特海温的快车 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What was the mistake the author made? We have learnt to expect that trains will be punctual. After years of conditioning, most of us have developed an unshakable faith in railway timetables. Ships may be delayed by storms; flights may be cancelled because of bad weather, but trains must be on time. Only an exceptionally heavy snowfall might temporarily dislocate railway services. It is all too easy to blame the railway authorities when something does go wrong. The truth is that when mistakes occur, they are more likely to be ours than theirs. After consulting my railway timetable, I noted with satisfaction that there was an express train to Westhaven. It went direct from my local station and the journey lasted mere hour and seventeen minutes. When I boarded the train, I could not help noticing that a great many local people got on as well. At the time, this did not strike me as odd. I reflected that there must be a great many local people besides myself who wished to take advantage of this excellent service. Neither was I surprise when the train stopped at Widley, a tiny station a few miles along the line. Even a mighty express train can be held up by signals. But when the train dawdled at station after station, I began to wonder, It suddenly dawned on me that this express was not roaring down the line at ninety miles an hour, but barely chugging along at thirty. One hour and seventeen minutes passed and we had not even covered half the distance. I asked a passenger if this was the Westhaven Express, but he had not even heard of it. I determined to lodge a complaint as soon as we arrived. Two hours later, I was talking angrily to the station master at Westhaven. When he denied the train's existence, I borrowed his copy of the timetable. There was a note of triumph in my voice when I told him that it was there in black and white. Glancing at it briefly, he told me to look again. A tiny asterisk conducted me to a footnote at the bottom of the page. It said: 'This service has been suspended.' New words and expressions 生词和短语 express n. 快车； adj. 高速的 punctual adj. 准时的 condition v. 使习惯于 unshakable adj. 不可动摇的 faith n. 信任 cancel v. 取消 exceptionally adv. 例外地 dislocate v. 打乱（计划等） blame v. 责怪 consult v. 请教，查阅 direct adv. 径直地 odd adj. 奇怪的，异常的 reflect v. 细想 advantage n. 优势 mighty adj. 强大的，有力的 dawdle v. 慢吞吞地动或做 chug v. 咔嚓咔嚓地响 lodge v. 提出 complaint n. 抱怨 triumph n. 胜利 asterisk n. 星号（*） conduct v. 引向，引导 参考译文 我们已经习惯于相信火车总是准点的。经过多年的适应，大多数人对火车时刻表产生了一种不可动摇的信念。轮船船期可能因风暴而推延，飞机航班可能因恶劣天气而取消，唯有火车必然是准点的。只有非同寻常的大雪才可能暂时打乱铁路运行。因此，一旦铁路上真出了问题，人们便不加思索地责备铁路当局。事实上，差错很可能是我们自己，而不是铁路当局的。 我查看了列车时刻表，满意地了解到有一趟去威斯特海温的快车。这是趟直达车，旅途总共才需1小时17分钟。上车后，我不禁注意到许多当地人也上了车。一开始，我并不感到奇怪，我想除我之外，想利用快车之便的也一定大有人在。火车开出几英里即在一个小站威德里停了下来。对此，我不觉得奇怪，因为即便是特别快车也可能被信号拦住。但是，当火车一站接着一站往前蠕动时，我便产生了怀疑。我突然感到这趟快车并没以时速90英里的速度呼啸前进，而是卟哧卟哧地向前爬行，时速仅30英里。1小时17分过去了，走了还不到一半路程。我问一位乘客，这是不是开往威斯特海温的那趟快车，他说从未听说过有这么一趟快车。我决定到目的地就给铁路部门提意见。两小时后，我气呼呼地同威斯特海温站站长说起此事。他说根本没有这趟车。于是我借他本人的列车时刻表，我带着一种胜利者的调子告诉他那趟车白纸黑字。明明白白印在时刻表上。他迅速地扫视了一眼，让我再看一遍。一个小小的星形符号把我的目光引到了那页底部一个说明上。上面写着：“此趟列车暂停运行。” Lesson 38 The first calender 最早的日历 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What is the importance of the dots, lines, and symbols engraved on some, bones and ivory? Future historians will be in a unique position when they come to record the history of our own times. They will hardly know which facts to select from the great mass of evidence that steadily accumulates. What is more, they will not have to rely solely on the written word. Films, videos, CDs and CD-ROMS are just some of the bewildering amount of information they will have. They will be able, as it were, to see and hear us in action. But the historian attempting to reconstruct the distant past is always faced with a difficult task. He has to deduce what he can from the few scanty clues available. Even seemingly insignificant remains can shed interesting light on the history of early man. Up to now, historians have assumed that calendars came into being with the advent of agriculture, for then man was faced with a real need to understand something about the seasons. Recent scientific evidence seems to indicate that this assumption is incorrect. Historians have long been puzzled by dots, lines and symbols which have been engraved on walls, bones, and the ivory tusks of mammoths. The nomads who made these markings lived by hunting and fishing during the last Ice Age which began about 35,000 B.C. and ended about 10,000 B.C. By correlating markings made in various parts of the world, historians have been able to read this difficult code. They have found that it is connected with the passage of days and the phases of the moon. It is, in fact, a primitive type of calendar. It has long been known that the hunting scenes depicted on walls were not simply a form of artistic expression. They had a definite meaning, for they were as near as early man could get to writing. It is possible that there is a definite relation between these paintings and the markings that sometimes accompany them. It seems that man was making a real effort to understand the seasons 20,000 years earlier than has been supposed. New words and expressions 生词和短语 calendar n. 历法，日历 historian n. 历史学家 unique adj. 无与伦比的 steadily adv. 不断地 solely adv. 唯一地 video n. 录像 CD-ROOM n. （只读）光盘驱动器 bewilder v. 令人眼花缭乱 deduce v. 推断，推理 scanty adj. 不足的，贫乏的 clue n. 线索 insignificant adj. 不重要的 shed v. 使流出，泻 advent n. 出现，到来，来临 agriculture n. 农业 assumption n. 假定，设想 dot n. 小圆点 symbol n. 符号 engrave v. 雕刻 ivory n. 象牙制品 mammoth n. （古）长毛象 tusk n. 獠牙，长牙，象牙 nomad n. 游牧民 correlate v. 使相互联系 phase n. 月相，天相 primitive adj. 原始的 depict v. 描画，描绘 参考译文 未来的历史学家在写我们这一段历史的时候会别具一格。对于逐渐积累起来的庞大材料，他们几乎不知道选取哪些好，而且，也不必完全依赖文字材料。电影、录像、光盘和光盘驱动器只是能为他们提供令人眼花缭乱的大量信息的几种手段。他们能够身临其境般地观看我们做事，倾听我们讲话。但是，历史学家企图重现遥远的过去可是一项艰巨的任务，他们必须根据现有的不充分的线索进行推理。即使看起来微不足道的遗物，也可能揭示人类早期历史的一些有趣的内容。 历史学家迄今认为日历是随农业的问世而出现的，因为当时人们面临着了解四季的实际需要，但近期科学研究发现，好像这种假设是不正确的。 长期以来，历史学家一直对雕刻在墙壁上、骨头上、古代长毛象的象牙上的点、线和形形色色的符号感到困惑不解。这些痕迹是游牧人留下的，他们生活在从公元前约35，000年到公元前10，000年的冰川期的末期，以狩猎、捕鱼为生。历史学家通过把世界各地留下的这种痕迹放在一起研究，终于弄懂了这种费解的代码。他们发现代码与昼夜更迭和月亮圆缺有关，事实上是一种最原始的日历。大家早就知道，画在墙上的狩猎图景并不是单纯的艺术表现形式，它们有着一定的含义，因为它们已接近古代人的文字形式。有时，这种图画与墙壁上的刻痕共存，它们之间可能有一定的联系。看来人类早就致力于探索四季变迁了，比人们想像的要早20,000年。 Lesson 39 Nothing to worry about 不必担心 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What was the difference between Bruce's behaviour and that of other people? The rough across the plain soon became so bad that we tried to get Bruce to drive back to the village we had come from. Even though the road was littered with boulders and pitted with holes, Bruce was not in the least perturbed. Glancing at his map, he informed us that the next village was a mere twenty miles away. It was not that Bruce always underestimated difficulties. He simply had no sense of danger at all. No matter what the conditions were, he believed that a car should be driven as fast as it could possibly go. As we bumped over eh dusty track, we swerved to avoid large boulders. The wheels scooped up stones which hammered ominously under the car. We felt sure that sooner or later a stone would rip a hole in our petrol tank or damage the engine. Because of this, we kept looking back, wondering if we were leaving a trail of oil and petrol behind us. What a relief it was when the boulders suddenly disappeared, giving way to a stretch of plain where the only obstacles were clumps of bushes. But there was worse to come. Just ahead of us there was a huge fissure. In response to renewed pleadings, Bruce stopped. Though we all got out to examine the fissure, he remained in the car. We informed him that the fissure extended for fifty years and was tow feet wide and four feet deep. Even this had no effect. Bruce went into a low gear and drove at a terrifying speed, keeping the front wheels astride the crack as he followed its zigzag course. Before we had time to worry about what might happen, we were back on the plain again. Bruce consulted the map once more and told us that the village was now only fifteen miles away. Our next obstacle was a shallow pool of water about half a mile across. Bruce charged at it, but in the middle, the car came to a grinding half. A yellow light on the dashboard flashed angrily and Bruce cheerfully announced that there was no oil in the engine! New words and expressions 生词和短语 rough adj. 崎岖不平的 boulder n. 大石块 pit v. 使得坑坑洼洼 perturb v. 使不安 underestimate v. 低估 swerve v. 急转变 scoop v. 挖出 hammer v. （用锤）击打，锤打 ominously adv. 有预兆的，不祥的 rip v. 划破，撕，扯 petrol n. 汽油 stretch n. 一大片（平地或水） obstacle n. 障碍 clump n. 丛，簇 fissure n. （石，地的）深缝 renew v. 重复 pleading n. 恳求 gear n. 汽车排档 astride prep.骑，跨 crack n. 缝隙 zigzag n. “之”字形 shallow adj. 浅的 grind (ground, ground) v. 磨擦 halt n. 停 dashboard n. （汽车上的）仪表盘 参考译文 穿越平原的道路高低不平，开车走了不远，路面愈加崎岖。我们想劝说布鲁斯把车开回我们出发的那个村庄去。尽管路面布满石头，坑坑洼洼，但布鲁斯却一点儿不慌乱。他瞥了一眼地图，告诉我们前面再走不到20英里就是一个村庄。这并不是说布鲁斯总是低估困难，而是他压根儿没有一点儿危险感。他认为不管路面情况如何，车必须以最高速度前进。 我们在尘士飞扬的道路上颠簸，车子东拐西弯，以躲开那些大圆石。车轮搅起的石块锤击车身，发出不祥的锤击声。我们想念迟早会飞起一个石块把油箱砸开一个窟窿，或者把发动机砸坏。因此，我们不时地掉过头，怀疑车后是否留下了机油和汽油的痕迹。 突然大石块不见了，前面是一片平地，唯一的障碍只有一簇簇灌木丛。这使我们长长地松了口气。但是更糟糕的事情在等着我们，离我们不远处，出现一个大裂缝。我们再次央求布鲁斯小心，他这才把车停了下来。我们纷纷下车察看那个大裂缝，他却呆在车上。我们告诉他那个大裂缝长50码，宽2英尺，深4英尺。这也没有对他产生任何影响。布鲁斯挂上慢档，把两只前轮分别搁在裂缝的两边，顺着弯弯曲曲的裂缝，以发疯的速度向前开去。我们还未来得及担心后果，车已重新开上了平地。布鲁斯又看了一眼地图，告诉我们那座村庄离我们只有15英里了。下一个障碍是一片约半英里宽的浅水塘。布鲁斯向水塘冲去，但车开到水塘当中，嘎吱一声停住了。仪表盘一盏黄灯闪着刺眼的光芒，布鲁斯兴致勃勃地宣布发动机里没油了！ Lesson 40 Who's who 真假难辨 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 How did the policeman discover that the whole thing was a joke? It has never been explained why university students seem to enjoy practical jokes more than else. Students specialize in a particular type of practical joke: the hoax. Inviting the fire brigade to put out a nonexistent fire is a crude form of deception which no self-respecting student would ever indulge in. Students often create amusing situations which are funny to everyone except the victims. When a student recently saw two workmen using a pneumatic drill outside his university, he immediately telephoned the police and informed them that two students dressed up as workmen were tearing up the road with a pneumatic drill. As soon as he had hung up, he went over to the workmen and told them that if a policeman ordered them to go away, they were not take him seriously. He added that a student had dressed up as a policeman and was playing all sorts of silly jokes on people. Both the police and the workmen were grateful to the student for this piece of advance information. The student did in an archway nearby where he could watch and hear everything that went on. Sure enough, a policeman arrived on the scene and politely asked the workmen to go away. When he received a very rude reply from one of the workmen. He threatened to remove them by force. The workmen told him to do as he pleased and the policeman telephoned for help. Shortly afterwards, four more policemen arrived and remonstrated with the workmen. As the men refused to stop working, the police attempted to seize the pneumatic drill. The workmen struggled fiercely and one of them lost his temper. He threatened to call the police. At this, the police pointed out ironically that this would hardly be necessary as the men were already under arrest. Pretending to speak seriously, one of the workmen asked if he might make a telephone call before being taken to the station. Permission was granted and a policeman accompanied him to a pay phone. Only when he saw that the man was actually telephoning the police did he realize that they had all been the victims of a hoax. New words and expressions 生词和短语 hoax n. 骗局，戏弄 deception n. 欺骗，骗局 self-respecting adj. 自重的 indulge v. 使沉迷 pneumatic adj. 气动的 drill n. 钻 silly adj. 无意义的，无聊的 advance adj. 预先的，事先获得的 archway n. 拱形门楼 remonstrate v. 规劝，告诫 ironically adv. 讽刺地 permission n. 许可 grant v. 同意，准予 参考译文 谁也弄不清为什么大学生好像比任何人都更喜欢恶作剧。大学生擅长一种特殊的恶作剧——戏弄人。请消防队来扑灭一场根本没有的大火是一种低级骗局，有自尊心的大学生决不会去做。大学生们常常做的是制造一种可笑的局面，使大家笑上一场，当然受害者是笑不出来的。 最近有个学生看见两个工人在学校门外用风钻干活，马上打电话报告警察，说有两个学生装扮成工人，正在用风钻破坏路面。挂上电话后，他又马上来到工人那儿，告诉他们若有个警察来让他们走开，不要把他当回事，还对工人说，有个学生常装扮成警察无聊地同别人开玩笑。警察与工人都对那个学生事先通报情况表示感谢。 那个学生躲在附近一拱形的门廊里，在那儿可以看见、听到现场发生的一切。果然，警察来了，不礼貌地请工人离开此地；但其中一个工人粗鲁地回了几句。于是警察威胁要强行使他们离开。工人说，悉听尊便。警察去打电话叫人。一会儿工夫，又来了4个警察，规劝工人离开。由于工人拒绝停下手中的活，警察想夺风钻。两个工人奋力抗争，其中一个发了火，威胁说要去叫警察。警察听后讥讽地说，这大可不必，因为他俩已被逮捕了。其中一个工人装模作样地问道，在被带往警察局之前，是否可以打一个电话。警察同意了，陪他来到一个投币地电话前，当他看到那个工人真的是给警察挂电话，才恍然大悟，原来他们都成一场骗局的受害者。 Lesson 41 Illusions of Pastoral peace 宁静田园生活的遐想 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 What particular anxiety spoils the country dweller's visit to the theatre? The quiet life of the country ahs never appealed to me. City born and city bred. I have always regarded the country as something you look at through a train window, or something you occasional visit during the weekend. Most of my friends live in the city, yet they always go into raptures at the mere mention of the country. Though they extol the virtues of the peaceful life, only one of hem has ever gone to live in the country and he was back in town within six months. Even he still lives under the illusion that country life is somehow superior to town life. He is forever talking about the friendly people, the clean atmosphere, the closeness to nature and the gentle pace of living. Nothing can be compared, he maintains, with the first cockcrow, the twittering of birds at dawn, the sight of the rising sun glinting on the trees and pastures. This idyllic pastoral scene is only part of the picture. My friend fails to mention the long and friendless winter evenings in front of the TV -- virtually the only form of entertainment. He says nothing about the poor selection of goods in the shops, or about those unfortunate people who have to travel from the country to the city every day to get to work. Why people are prepared to tolerate a four-hour journey each day for the dubious privilege of living in the country is beyond me. They could be saved so much misery and expense if they chose to live in the city where they rightly belong. If you can do without the few pastoral pleasures of the country, you will find the city can provide you with the best that life can offer. You never have to travel miles to see your friends. They invariably lie nearby and are always available for an informal chat or an evening's entertainment. Some of my acquaintances in the country come up to town once or twice a year to visit the theatre as a special treat. For them this is a major operation which involves considerable planning. As the play draws to its close, they wonder whether they will ever catch that last train home. The cit dweller never experiences anxieties of this sort. The latest exhibitions, films, or plays are only a short bus ride away. Shopping, too, is always a pleasure. The latest exhibitions, films, or plays are only a short bus ride away. Shopping, too, is always a pleasure. There is so much variety that you never have to make do with second best. Country people run wild when they go shopping in the city and stagger home loaded with as many of the exotic items as they can carry. Nor is the city without its moments of beauty. There is something comforting about the warm glow shed by advertisements on cold wet winter nights. Few things could be more impressive than the peace that descends on deserted city streets at weekends when the thousands that travel to work every day are tucked away in their homes in the country. It has always been a mystery to me who city dwellers, who appreciate all these things, obstinately pretend that they would prefer to live in the country. New words and expressions 生词和短语 illusion n. 幻想，错觉 pastoral adj. 田园的 breed (bred, bred) v. 培育 rapture n. 欣喜 extol v. 赞美，颂扬 superior adj. 优越的 cockcrow n. 鸡叫 twitter v. （鸟）吱吱叫，嘁嘁喳喳叫 glint v. 闪烁 pasture n. 牧场 idyllic adj. 田园诗的 virtually adv. 几乎，差不多 dubious adj. 可疑的，怀疑的 privilege n. 特权 misery n. 苦难 acquaintance n. 熟人 treat n. 难得的乐事，享受 dweller n. 居住者 stagger v. 摇晃，蹒跚 exotic adj. 导乎寻常的，外来的 glow n. 白炽光 descend v. 缩进，隐藏 descend v. 缩进，隐藏 obstinately adv. 固执地，顽固地 参考译文 宁静的乡村生活从来没有吸引过我。我生在城市，长在城市，总认为乡村是透过火车车窗看到的那个样了，或偶尔周末去游玩一下景象。我的许多朋友都住在城市，但他们只要一提起乡村，马上就会变得欣喜若狂。尽管他们都交口称赞宁静的乡村生活的种种优点，但其中只有一个人真去农村住过，而且不足6个月就回来了。即使他也仍存有幻觉，好像乡村生活就是比城市生活优越。他滔滔不绝地大谈友好的农民，洁净的空气，贴近大自然的环境和悠闲的生活节奏。他坚持认为，凌晨雄鸡第一声啼叫，黎明时分小鸟吱喳欢叫，冉冉升起的朝阳染红树木、牧场，此番美景无与伦比。但这种田园诗般的乡村风光仅仅是一个侧面。我的朋友没有提到在电视机前度过的漫长寂寞的冬夜——电视是唯一的娱乐形式。他也不说商店货物品种单调，以及那些每天不得不从乡下赶到城里工作的不幸的人们。人们为什么情愿每天在路上奔波4个小时去换取值得怀疑的乡间的优点，我是无法理解的。要是他们愿意住在本来属于他们的城市，则可以让他们省去诸多不便与节约大量开支。 如果你愿舍弃乡下生活那一点点乐趣的话，那么你会发出城市可以为你提供生活最美好的东西。你去看朋友根本不用跋涉好几英里，因为他们都住在附近，你随时可以同他们聊天或在晚上一起娱乐。我在乡村有一些熟人，他们每年进城来看一回或几回戏，并把此看作一种特殊的享受。看戏在他们是件大事，需要精心计划。当戏快演完时，他们又为是否能赶上末班火车回家而犯愁。这种焦虑，城里人是从未体验过的。坐公共汽车几站路，就可看到最新的展览、电影、戏剧。买东西也是一种乐趣。物品种繁多，从来不必用二等品来凑合。乡里人进城采购欣喜若狂，每次回家时都买足了外来商品，直到拿不动方才罢休，连走路都摇摇晃晃的。城市也并非没有良辰美景。寒冷潮湿的冬夜里，广告灯箱发出的暖光，会给人某种安慰。周末，当成千上万进城上班的人回到他们的乡间寓所之后，空旷的街市笼罩着一种宁静气氛，没有什么能比此时的宁静更令人难忘了。城里人对这一切心里很明白，却偏要执拗地装出他们喜欢住在乡村的样子，这对我来说一直是个谜。 Lesson 42 Modern cavemen 现代洞穴人 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 With what does the writer compare the Gouffre Berger? Cave exploration, or pot-holing, as it has come to be known, is a relatively new sport. Perhaps it is the desire for solitude or the chance of making an unexpected discovery that lures people down to the depths of the earth. It is impossible to give a satisfactory explanation for a pot-holer's motives. For him, caves have the same peculiar fascination which high mountains have for the climber. They arouse instincts which can only be dimly understood. Exploring really deep caves is not a task for the Sunday afternoon rambler. Such undertakings require the precise planning and foresight of military operations. It can take as long as eight days to rig up rope ladders and to establish supply bases before a descent can be made into a very deep cave. Precautions of this sort are necessary, for it is impossible to foretell the exact nature of the difficulties which will confront the pot-holer. The deepest known cave in the world is the Gouffre Berger near Grenoble. It extends to a depth of 3,723 feet. This immense chasm has been formed by an underground stream which has tunneled a course through a flaw in the rocks. The entrance to the cave is on a plateau in the Dauphine Alps. As it is only six feet across, it is barely noticeable. The cave might never have been discovered has not the entrance been spotted by the distinguished French pot-holer, Berger. Since its discovery, it has become a sort of potholers' Everest. Though a number of descents have been made, much of it still remains to be explored. A team of pot-holers recently went down the Gouffre Berger. After entering the narrow gap on the plateau, they climbed down the steep sides of the cave until they came to narrow corridor. They had to edge their way along this, sometimes wading across shallow streams, or swimming across deep pools. Suddenly they came to a waterfall which dropped into an underground lake at the bottom of the cave. They plunged into the lake, and after loading their gear on an inflatable rubber dinghy, let the current carry them to the other side. To protect themselves from the icy water, they had to wear special rubber suits. At the far end of the lake, they came to huge piles of rubble which had been washed up by the water. In this part of the cave, they could hear an insistent booming sound which they found was caused by a small waterspout shooting down into a pool from the roof of the cave. Squeezing through a cleft in the rocks, the pot-holers arrived at an enormous cavern, the size of a huge concert hall. After switching on powerful arc lights, they saw great stalagmites -- some of them over forty feet high -- rising up like tree-trunks to meet the stalactites suspended from the roof. Round about, piles of limestone glistened in all the colours of the rainbow. In the eerie silence of the cavern, the only sound that could be heard was made by water which dripped continuously from the high dome above them. New words and expressions 生词和短语 caveman n. （远古）洞穴人 pot-holing n. 洞穴探险，洞穴探险运动 solitude n. 孤独，寂寞 lure v. 引诱，诱惑 pot-holer n. 洞穴探险者 undertaking n. 任务，工作 foresight n. 预见；深谋远虑 foretell v. 预言 Grenoble n. 格里诺布尔 chasm n. 断层，裂口，陷坑 flaw n. 小裂缝 distinguished adj. 杰出的，著名的 Everest n. 珠穆朗玛峰 wade v. 涉水 waterfall n. 瀑布 gear n. 一套用具 inflatable adj. 可充气的 rubble n. 碎瓦 insistent adj. 连续的，不断的 boom v. 轰响 waterspout n. 强大的水柱 cleft n. 裂隙，开 cavern n. 在洞穴 stalagmite n. 石笋 stalactite n. 钟乳石 limestone n. 石灰石 glisten v. 闪烁 cerie adj. 引塌恐惧的，可怕的 dome n. 穹窿，圆顶 参考译文 洞穴勘查——或洞穴勘探——是一项比较新的体育活动。寻求独处的愿望或寻求意外发现的机会的欲望吸引人们来到地下深处。要想对洞穴探险者的动机作出满意的解释是不可能的。对洞穴探险者来说，洞穴有一种特殊的魅力，就像高山对登山者有特殊魅力一样。为什么洞空能引发人的那种探险本能，人们对此只能有一种模模糊糊的理解。 探测非常深的洞穴不是那些在星期日下午漫步的人所能胜任的。这种活动需要有军事行动般的周密布署和预见能力。有时需要花费整整8天时间来搭起绳梯，建立供应基地，然后才能到一个很深的洞穴里。作出这样的准备是必要的，因为无法预见到洞穴探险者究竟会遇到什么性质的困难。世界上最深的洞穴是格里诺布尔附近的高弗.伯杰洞，深达3,723英尺。这个深邃的洞穴是由一条地下暗泉冲刷岩石中的缝隙并使之慢慢变大而形成的。此洞的洞口在丹芬阿尔卑斯山的高原上，仅6英尺宽，很难被发现。若不是法国著名洞穴探险家伯杰由于偶然的机会发现了这个洞口的话，这个洞也许不会为人所知。自从被发现以后，这个洞成了洞穴探险者的珠穆朗玛峰，人们多次进入洞内探险，但至今尚有不少东西有待勘探。 最近，一队洞穴探险者下到了高弗.伯杰洞里。他们从高原上的窄缝进去，顺着笔直陡峭的洞壁往下爬。来到一条狭窄的走廊上。他们不得不侧着身子往前走，有时过浅溪，有时游过深潭。突然，他们来到一道瀑布前，那瀑布奔泻而下，注入洞底一处地下湖里。他们跳入湖中，把各种器具装上一只充气的橡皮艇，听任水流将他们带往对岸。湖水冰冷刺骨，他们必须穿上一种特制的橡皮服以保护自己。在湖的尽头，他们见到一大堆一大堆由湖水冲刷上岸的碎石。在这儿，他们可以听见一种连续不断的轰鸣声。后来他们发现这是由山洞顶部的一个小孔里喷出的水柱跌落到水潭中发出的声音。洞穴探险者从岩石缝里挤身过去，来到一个巨大的洞里，其大小相当于一个音乐厅。他们打开强力弧光灯，看见一株株巨大的石笋，有的高达40英尺，像树干似地向上长着，与洞顶悬挂下来的钟乳石相接。周围是一堆堆石灰石，像彩虹一样闪闪发光。洞里有一种可怕的寂静，唯一的可以听见的声响是高高的圆顶上不间断地滴水的嘀嗒声。 Lesson 43 Fully insured 全保险 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Who owned the pie and why? Insurance companies are normally willing to insure anything. Insuring public or private property is a standard practice in most countries in the world. If, however, you were holding an open air garden party or a fete it would be equally possible to insure yourself in the event of bad weather. Needless to say, the bigger the risk an insurance company takes, the higher the premium you will have to pay. It is not uncommon to hear that a shipping company has made a claim for cost of salvaging a sunken ship. But the claim made by a local authority to recover the cost of salvaging a sunken pie dish must surely be unique. Admittedly it was an unusual pie dish, for it was eighteen feet long and six feet wide. It had been purchased by a local authority so that an enormous pie could be baked for an annual fair. The pie committee decided that the best way to transport the dish would be by canal, so they insured it for the trip. Shortly after it was launched, the pie committee went to a local inn to celebrate. At the same time, a number of teenagers climbed on to the dish and held a little party of their own. Dancing proved to be more than the dish could bear, for during the party it capsized and sank in seven feet of water. The pie committee telephoned a local garage owner who arrived in a recovery truck to salvage the pie dish. Shivering in their wet clothes, the teenagers looked on while three men dived repeatedly into the water to locate the dish. They had little difficulty in finding it, but hauling it out of the water proved to be a serious problem. The sides of the dish were so smooth that it was almost impossible to attach hawsers and chains to the rim without damaging it. Eventually chains were fixed to one end of the dish and a powerful winch was put into operation. The dish rose to the surface and was gently drawn towards the canal bank. For one agonizing moment, the dish was perched precariously on the bank of the canal, but it suddenly overbalanced and slid back into the water. The men were now obliged to try once more. This time they fixed heavy metal clamps to both sides of the dish so that they could fasten the chains. The dish now had to be lifted vertically because one edge was resting against the side of the canal. The winch was again put into operation and one of the men started up the truck. Several minutes later, the dish was again put into operation and one of the water. Water streamed in torrents over its sides with such force that it set up a huge wave in the canal. There was danger that the wave would rebound off the other side of the bank and send the dish plunging into the water again. By working at tremendous speed, the men managed to get the dish on to dry land before the wave returned. New words and expressions 生词和短语 admittedly adv. 公认地 purchase v. 买 annual adj. 一年一度的 teenager n. （13至19岁的）青少年 capsize v. （船）翻 shiver v. 打颤，发抖 dive v. （头向下）跳水 haul v. 拖曳 hawser n. 粗缆绳 rim n. （圆形物品的）外沿，边 winch n. 绞车 agonizing adj. 精神紧张的，提心吊胆的 perch v. 处于（高处） precariously adv. 危险地，不稳固地 overbalance v. 失去平衡 clamp n. 夹钳，夹板 vertically adv. 垂直地 torrent n. 激流，洪流 rebound v. 弹回 参考译文 保险公司一般说来愿意承保一切东西。承办公共财产或私人财产保险是世界上大部分国家的正常业务。如果你要举办一次露天游园会或盛宴，为避免碰上不好的天气而遭受损失也同样可以保险，不用说，保险公司承担风险越大，你付的保险费也就越高。航运公司为打捞沉船而提出索赔，这是常有的事，但某地当局为打捞一只焙制馅饼的盘子提出索赔，倒是件新鲜的事儿。 这个馅饼盘子确实少见，有18英尺长，6英尺宽。某地方当局买下它用来焙制一个巨大的馅饼为一年一度交易会助兴。馅饼委员会确认运输这只盘子的最佳方案是通过运河水运。于是，他们对这只盘子的运输安全投了保。盘子下水后不久，馅饼委员会成员们来到当地一家小酒店庆贺。就在这个时候，许多十几岁的孩子爬盘子举行他们自己的集会。他们跳起了舞，盘子难以承受。舞会进行过程中，盘子倾覆，沉入了7英尺深的水中。 馅饼委员会给当地汽车修理库老板打电话，他闻讯后开着一辆急修车前来打捞盘子。那些孩子们穿着湿衣服哆嗦，看着3个工人轮潜入水中以确定盘子的位置。他们没费多大事儿就找到了盘子。可是把盘子捞出却是一个很大的难题。盘子四边十分光滑，要在盘边拴上绳索或链条而同时又不损坏它是很难办到的。不过，他们终于将链条固定在盘子的一端，一台大功率的绞车开动起来。盘子慢慢浮出水面，被轻轻地拽向运河岸边。在令人忐忑不安的瞬间，盘子晃晃悠悠地上了岸，但它突然失去了平衡，又跌回水中。工人们只得再来一次。这次，他们用沉重的金属夹子把盘子夹住，以便往盘子上安装铁链。这次，盘子必须垂直吊出水面，因为盘子的一边紧靠着运河河岸。绞盘机再次启动，一位工人发动了急修车的引擎。几分钟后，盘子被成功地拽出了水面。波浪从盘子两侧急涌而出，在运河里掀起一股大浪。但是当波浪从河对岸折回来时，就有再次把盘子拖进水里的危险。工人们动作迅速，终于赶在那股大浪返回之前把盘子拽到了岸上。 Lesson 44 Speed and comfort 又快捷又舒适 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Which type of transport does the writer prefer, do you think? People travelling long distances frequently have to decide whether they would prefer to go by land, sea, or air. Hardly anyone can positively enjoy sitting in a train for more than a few hours. Train compartments soon get cramped and stuffy. It is almost impossible to take your mind off the journey. Reading is only a partial solution, for the monotonous rhythm of the wheels clicking on the rails soon lulls you to sleep. During the day, sleep comes in snatches. At night, when you really wish to go to sleep, you rarely manage to do so. If you are lucky enough to get a sleeper, you spend half the night staring at the small blue light in the ceiling, or fumbling to find you ticket for inspection. Inevitably you arrive at your destination almost exhausted. Long car journeys are even less pleasant, for it is quite impossible even to read. On motorways you can, at least, travel fairly safely at high speeds, but more often than not, the greater part of the journey is spent on roads with few service stations and too much traffic. By comparison, ferry trips or cruises offer a great variety of civilized comforts. You can stretch your legs on the spacious decks, play games, meet interesting people and enjoy good food -- always assuming, of course, that the sea is calm. If it is not, and you are likely to get seasick, no form of transport could be worse. Even if you travel in ideal weather, sea journeys take a long time. Relatively few people are prepared to sacrifice holiday time for the pleasure of travlling by sea. Aeroplanes have the reputation of being dangerous and even hardened travellers are intimidated by them. They also have the disadvantage of being an expensive form of transport. But nothing can match them for speed and comfort. Travelling at a height of 30,000 feet, far above the clouds, and at over 500 miles an hour is an exhilarating experience. You do not have to devise ways of taking your mind off the journey, for an aeroplane gets you to your destination rapidly. For a few hours, you settle back in a deep armchair to enjoy the flight. The real escapist can watch a film and sip champagne on some services. But even when such refinements are not available, there is plenty to keep you occupied. An aeroplane offers you an unusual and breathtaking view of the world. You soar effortlessly over high mountains and deep valleys. You really see the shape of the land. If the landscape is hidden from view, you can enjoy the extraordinary sight of unbroken cloud plains that stretch out for miles before you, while the sun shines brilliantly in a clear sky. The journey is so smooth that there is nothing to prevent you from reading or sleeping. However you decide to spend your time, one thing is certain: you will arrive at your destination fresh and uncrumpled. You will not have to spend the next few days recovering from a long and arduous journey. New words and expressions 生词和短语 positively adv. 绝对地，完全地 compartment n. 列车客车厢内的分隔间（或单间） cramped adj. 窄小的 stuffy adj. 憋气的，闷气的 monotonous adj. 枯燥的，乏味的 rhythm n. 有节奏的运动 click v. 发出咔哒声 lull v. 催人欲睡 snatch n. 短时，片段 sleeper n. 卧铺 fumble v. 乱摸，摸索 inspection n. 检查 inevitably adv. 必然地，不可避免地 destination n. 目的地 exhaust v. 使精疲力尽 motorway n. 快车道 ferry n. 渡船 cruise n. 巡游船 civilize v. 使文明 spacious adj. 宽敞的 seasick adj. 晕船的 intimidate v. 恐吓，恫吓 disadvantage n. 短处，缺点 exhilarating adj. 使人高兴的，令人兴奋的 escapist n. 逍遥者 sip v. 呷，啜 champagne n. 香槟洒 refinement n. 精心的安排 breathtaking adj.激动人心的；不寻常的 soar v. 高飞，翱翔 effortlessly adv. 不费力地 landscape n. 景色 fresh adj. 精神饱满的 uncrumpled adj. 没有垮下来 参考译文 出远门的人常常需要决定是走旱路、水路，还是坐飞机。很少有人能够真正喜欢坐几个小时以上的火车。车厢很快就变得拥挤、闷热，想摆脱开旅途的困扰是很难的。看书只能解决部分问题。车轮与铁轨间单调的嘎喳声很快就会送你进入梦乡。白天是忽睡忽醒，到了夜晚，你真想睡了，却很难入睡。即使你走运弄到一个卧铺，夜间有一半时间你会盯着车顶那盏小蓝灯而睡不着觉；要不然就为查票摸索你的车票。一旦抵达目的地，你总是疲惫不堪。乘汽车作长途旅行则更加不舒服，因为连看书都几乎不可能。在公路上还好，你至少能以相当快的速度安全地向前行。但旅行的大部分时间都花在路上，而且只有很少的服务设施，交通也很拥挤。相比之下，坐船旅行或环游可以得到文明世界的各种享受。你可以在甲板上伸展四肢、做游戏，还能也很见到各种有趣的人，能享用各种美味佳肴——当然，这一切只有在大海风平浪静的情况下才有可能。如果大海肆虐起来，你就可能晕船，那种难受劲儿是任何一种别的旅行的方式都不会带来的。即使风平浪静，坐船旅行也要占用很长时间。没有多少人会为享受坐船旅行的乐趣而牺牲假期的时间。 飞机以危险而著称，连老资格的旅行者也怕飞机。飞机另一个缺点是昂贵。但就速度与舒适而言，飞机是无与伦比的。腾云驾雾，在30，000 英尺高空以500英里的时速旅行，这种经历令人心旷神怡。你不必想办法去摆脱旅途的困扰，因为飞机会迅速地把你送到目的地。几小时之内，你躺在扶手椅上，享受着旅途的欢乐。真正会享受的人还可以在某些航班上看一场电影和喝香槟。即使没有这些消遣条件，也总是有事可做。飞机上，你可以观察世界上非同寻常的奇妙的美景。你毫不费劲地飞越高山幽谷，你确能饱览大地的风貌。如果这种景色被遮住了，你可以观赏一下展现在你面前的、一望数英里的、连绵不断的云海，同时阳光灿烂，天空清澈明朗。旅途平稳，丝毫不妨碍你阅读或睡眠。不管你打算如何消磨时间，有件事是可以肯定的，即当你抵达目的地时，你感到精神焕发，毫无倦意，用不着因为漫长的旅途的辛苦而花几天时间休息来恢复精神。 Lesson 45 The power of the press 新闻报道的威力 Listen to the tape then answer the question below. 听录音，然后回答以下问题。 Does the writer think the parents where lucky or unlucky to gain prosperity in this way? Why? In democratic countries any efforts to restrict the freedom of the press are rightly condemned. However, this freedom can easily be abused. Stories about people often attract far more public attention than political events. Though we may enjoy reading about the lives of others, it is extremely doubtful whether we would equally enjoy reading about ourselves. Acting on the contention that facts are sacred, reporters can cause untold suffering to individuals by publishing details about their private lives. Newspapers exert such tremendous influence that they can not only bring about major changes to the lives of ordinary people but can even overthrow a government. The story of a poor family that acquired fame and fortune overnight, dramatically illustrates the power of the press. The family lived in Aberdeen, a small town of 23,000 inhabitants in South Dakota. As the parents had five children, life was a perpetual struggle against poverty. They were expecting their sixth child and were faced with even more pressing economic problems. If they had only had one more child, the fact would have passed unnoticed. They would have continued to struggle against economic odds and would have lived in obscurity. But they suddenly became the parents of quintuplets, an aeroplane arrived in Aberdeen bringing sixty reporters and photographers. The rise to fame was swift. Television cameras and newspapers carried the news to everyone in the country. Newspapers and magazines offered the family huge sums for the exclusive rights to publish stories and photographs. Gifts poured in not only from unknown people, but room baby food and soap manufacturers who wished to advertise their products. The old farmhouse the family lived in was to be replaced by new$500,000 home. Reporters kept pressing for interviews so lawyers had to be employed to act as spokesmen for the family at press conferences. While the five babies were babies were still quietly sleeping in oxygen tents in hospital nursery, their parents were paying the price for fame. It would never again be possible for them to lead normal lives. They had become the victims of commercialization, for their names had acquired a market value. Instead of being five new family members, these children had immediately become a commodity.
New words and expressions 生词和短语
democratic
restrict
v. 限制
abuse
v. 滥用
contention
n. 论点
untold
South Dakota
南达科他州（美国）
perpetual
quintuplet
n. 五胞胎之一
obscurity
n. 默默无闻
exclusive
nursery
n. 育婴室，保育室
commercialization
n. 商品化
commodity
n. 商品
在民主国家里，任何限制新闻自由的企图都理所当然地受到谴责。然而，这种自由很容易被滥用。常人轶事往往比政治事件更能引起公众注意。我们都喜欢看关于别人生活的报道，但是否同样喜欢看关于自己生活的报道，就很难说了。记者按事实至上的论点行事，发表有关别人生活的细节，有时会给当事人造成极大的痛苦。新闻具有巨大的威力。它们不仅可以给寻常人家的生活带来重大的变化，甚至还能推翻一个政府。
下面这户穷人一夜之间出名发财的故事戏剧性地说明了新闻报道威力。这户人家住在南达科他州一个人口为23，000 的小镇上，镇名为阿拜丁。家里已有5个孩子，全家人常年在贫困中挣扎。第6个孩子即将问世，他们面临着更为严峻的经济问题。如果他们只添了1个孩子，这件事本来就不会引起任何人的注意。这家人会继续为克服经济上的拮据而奋斗，并默默无闻地活下去。但是他们出人意料生了个五胞胎，4女1男。这事使他们的生活发生了根本的变化。五胞胎降生第二天，一架飞机飞抵阿拜丁，随机带来60名记者与摄影师。
这一家迅速出了名。电视摄像机和报纸把消息传送到全国。报纸、杂志出高价向他们购买文字、图片的独家报道权。不但素昧平生的人寄来了大量的礼物，而且婴儿食品、婴儿肥皂制造厂商为了替自己产品做广告也寄来了大量的礼物。这家人住的旧家舍将由一座价值50万美元的新住宅所取代。由于记者纷纷要求会见，他们不得不请了律师充当他们家的发言人举行记者招待会。眼下，五胞胎还静静地躺在医院婴儿室的氧气帐里，他们的父母却为这名声付出了代价，他们再也无法过正常的生活。他们成了商业化的受害者，因为他们的名字具有了市场价值。这些孩子立即成了商品，而不是5个新的家庭成员。
Lesson 46
Do it yourself
自己动手
Listen to the tape then answer the question below.
Did the writer repair his lawn mower in the end? Why/Why not?
So great is our passion for doing things for ourselves, that we are becoming increasingly less dependent on specialized labour. No one can plead ignorance of a subject any longer, for these are countless do-it-yourself publications. Armed with the right tools and materials, newlyweds gaily embark on the task of decorating their own homes. Men, particularly, spend hours of their leisure time installing their own fireplaces, laying out their own gardens; building garages and making furniture. Some really keen enthusiasts go so far as to build their own computers. Shops cater for the do-it-yourself craze not only by running special advisory services for novices, but by offering consumers bits and pieces which they can assemble at home. Such things provide an excellent outlet for pent up creative energy, but unfortunately not all of us are born handymen.
Some wives tend to believe that their husbands are infinitely resourceful and can fix anything. Even men who can hardly drive a nail in straight are supposed to be born electricians, carpenters, plumbers and mechanics. When lights fuse, furniture gets rickety, pipes get clogged, or vacuum cleaners fail to operate, some woman assume that their husbands will somehow put things right. The worst thing about the do-it-yourself game is that sometimes even men live under the delusion that they can do anything, even when they have repeatedly been proved wrong. It is a question of pride as much as anything else.
New words and expressions 生词和短语
v. 找（借口），辩解
ignorance
n. 无知，不懂
publication
n. 出版物
newlyweds
n. 新婚夫妇
gaily
leisure
n. 空闲
keen
novice
n. 新手
consumer
n. 消费者，顾客
assemble
v. 装配，组装
outlet
n. 出路
creative
handyman
n. 手巧的人，能工巧匠
resourceful
fuse
v. 由于烧断保险丝而短路
rickety
clog
v. 堵塞
delusion
n. 错觉
lawn mower
割草机
n. 调整
screw
n. 螺丝钉
dismantle
v. 拆卸
chunk
n. （厚）块
snap
v. 绷断
insurmountable
jigsaw
n. 线锯
nag
v. 唠叨不休
rust
v. 生锈
现在我们自己动手做事的热情很高，结果对于专业工人的依赖越来越少了。由于出版了不计其数的教人自己动手做事的书报杂志，没有人再能说对某事一无所知。新婚夫妇找来合适的工具和材料，喜气洋洋地开始布置新房。特别是男人，常利用空闲时间安装壁炉、布置花园、建造车库、制作家具。有些热衷于自己动手的人甚至自己组装电脑。为了满足自己动手热的需要，商店不仅为初学者提供专门的咨询服务，而且为顾客准备了各种零件，供他们买回家去安装。这些东西为人们潜在的创造力提供了一个绝妙的用武之地。但不幸的是，我们并非人人都是能工巧匠。
妻子常常认为她们的丈夫无比聪明能干。甚至那些连一枚钉子都钉不直的男人都被认为是天生的电工、木匠、水管工和机械师。每当电灯保险丝烧断、家具榫头松动、管道堵塞、吸尘器不动时，有些妻子认为丈夫总有办法。自己动手的例子中最糟糕的是，有时甚至是男人尽管接连失败却还误以为自己什么都行，原因就是要面子。
今年春天，妻子让我请人检查一下我家的割草机。那台割草机去年夏天就坏了，尽管我答应修，但一直没抽出时间，我不愿听妻子的建议，说我自己会修。一个星期六的下午，我把割草机拉到了花园里，仔细检查了一番。在我看来，只需稍加调整即可。这儿紧紧螺丝，那儿固定一下，再加几滴油，就会像新的一样了。事实上，修理工作远不是那么简单。修完后割草机还是纹丝不动。于是，我决定把它拆开。一会儿工夫，割草机便被拆成一个个金属零件，乱七八糟地堆在花园里。但我却非常高兴，因为我找到了毛病所在。驱动轮子的链条断了一节。我买来一根新链条后，面临的就是如何把这些令人眼花缭乱的拼板重新组装起来。等我装完后，那台割草机仍然一动不动，对此我倒并不感到吃惊。原因很简单，因为还剩下几个形状奇特的零件似乎哪里也装不上去。我无可奈何，只好罢休。几个星期过去了，草长了起来。妻子喋喋不休让我想点办法。我告诉她，要么买一台新割草机，要么让草长下去。不用说，我家现在已被丛林包围。深草丛中的某个地方有一台正在生锈的割草机，那就是我曾答应某日要修理的割草机。
Lesson 47
Too high a price?
代价太高？
Listen to the tape then answer the question below.
What does the writer describe as an 'amusing old-fashioned source of noise'?
Pollution is the price we pay for an overpopulated, over industrialized planet. When you come to think about it, there are only four ways you can deal with rubbish: dump it, burn it, turn it into something you can use again, attempt to produce less of it. We keep trying all four methods, but he sheer volume of rubbish we produce worldwide threatens to overwhelm us.
Rubbish, however, is only part of the problem of polluting our planet. The need to produce ever-increasing quantities of cheap food leads to a different kind of pollution. Industrialized farming methods produce cheap meat products: beef, pork and chicken. The use of pesticides and fertilizers produces cheap grain and vegetables. The price we pay for cheap food may be already too high: Mad Cow Disease (BSE) in cattle, salmonella in chicken and eggs, and wisteria in dairy products. And if you think you'll abandon meat and become a vegetarian, you have the choice of very expensive organically-grown vegetables or a steady diet of pesticides every time you think you're eating fresh salads and vegetables, or just having an innocent glass of water!
However, there is an even more insidious kind of pollution that particularly affects urban areas and invades our daily lives, and that is noise. Burglar alarms going off at any time of the day or night serve only to annoy passers-by and actually assist burglars to burgle. Car alarms constantly scream at us in the street and are a source of profound irritation. A recent survey of the effects of noise revealed (surprisingly?) that dogs barking incessantly in the night rated the highest form of noise pollution on a scale ranging from 1 to 7. The survey revealed a large number of sources of noise that we really dislike. Lawn mowers whining on a summer's day, late-night parties in apartment blocks, noisy neighbors, vehicles of al kinds, especially large container trucks thundering through quiet village, planes and helicopters flying overhead, large radios carried round in public places and played at maximum volume. New technology has also made its own contribution to noise. A lot of people object to mobile phones, especially when they are used in public places like restaurants or on public transport. Loud conversations on mobile phones invade our thoughts or interrupt the pleasure of meeting friends for a quiet chat. The noise pollution survey revealed a rather spurring and possibly amusing old fashioned source of noise. It turned out to be snoring! Men were found to be the worst offenders. It was revealed that 20% of men in their mid-thirties snore. This figure rises to a staggering 60% of men in their sixties. Against these figures, it was found that only 5% of women snore regularly, while the rest are constantly woken or kept awake by their trumpeting partners. Whatever the source of noise, one thing is certain: silence, it seems, has become a golden memory.
New words and expressions 生词和短语
pollution
n. 污染
overpopulated
over-industrialized
sheer
worldwide
overwhelm
v. 制服，使不知所措
pollute
v. 污染
pesticide
n. 杀虫剂
fertilizer
n. 肥料
salmonella
n. 沙门氏菌
listeria
n. 利斯特杆菌
vegetarian
n. 吃素的人
organically-grown
insidious
urban
burglar
n. 窃贼
burgle
v. 入室偷窃
scream
v. 尖叫
profound
irritation
n. 烦躁
incessantly
whine
v. 发呜呜声
helicopter
n. 直升飞机
maximum
technology
n. 技术
contribution
n. 贡献
mobile
snore
v. 打鼾
offender
v. 冒犯者
staggering
trumpet
v. 吹号
partner
n. 伙伴
污染就是我们为这个人口过密，过度工业化的星球所付出的代价。当我们开始考虑垃圾问题时，我们只有4种对付垃圾的方法：倾倒、焚烧、把垃圾变成再生材料或试图少产生一些垃圾。我们一直在试这4种方式，但是，我们在世界范围内仅产生的垃圾的量就有把我们覆盖的危险。
然而，垃圾只是我们这个星球的污染问题的一个方面。日益增长的对廉价食物的需求导致了另一种形式的污染。工业化的农作方式生产出廉价的肉类制品——牛肉、猪肉和鸡肉。使用杀虫剂和化肥生产出廉价的谷物和蔬菜。为了廉价食物我们付出代价已经太高了：牛肉中的疯牛病，鸡肉和鸡蛋中的沙门氏菌，奶制品中的利斯特杆菌。如果你想放弃肉类而变成一位素食者，那么你可以两者择一：或是选用价格昂贵、有机培植的蔬菜，或是当你认为在享用新鲜色拉和新鲜蔬菜或饮用一杯无害的水的时候，实际上每次都不断吃进杀虫剂。
但是，还有一种更加隐蔽有害的污染，它专门影响城镇地区，侵袭我们的日常生活，那就是噪音。防盗警报器在白天和黑夜的任何时候都会响起来，它的作用只是骚扰过路行人，而实际上却帮助窃贼入室行窃。在街上，汽车的防盗警报不断对我们吼叫，这是人们极度烦燥的一个原因，最近一个有关噪音的作用的调查（令人吃惊地）指出，夜间连续不断的狗叫声，在一个从1级至7级刻度表上应列为最严重的噪间污染。这个调查揭示了我们所不喜欢的大量的噪间的来源：夏天呜呜作响的割草机，公寓楼里深夜聚会的喧哗声，大声吵闹的邻居，各式各样的车辆，特别是穿越寂静的村庄的集装箱卡车，从头顶飞过的飞机和直升机，被带到公共场所、音量开到最大的大功率收音机。新技术也为噪音作了它的贡献。许多人都反对移动式电话，特别是在如饭店，公共交通车等公共场所使用移动电话。用移动电话大声交谈干扰我们的思路，破坏我们和朋友在一起轻声聊天所得到的乐趣。这个有关噪音的污染调查还揭示了一种出人意外而同时可能会引人意外而同时可能会引人发笑的老式噪音源。它竟然是鼾声。人类是这方面的罪魁祸首。调查指出，20%的35岁左右的男人打鼾；而到60岁这个年龄段，这个数字上升到令人惊愕的60%。与这些数字相比，只有5% 的女性经常打鼾；而其余则经常被与她们同睡、像吹号似地打着呼噜的男人吵醒或弄得睡不着。不管噪声来自何方，有一点是肯定的：看来寂静已变成一种珍贵的回忆。
Lesson 48
The silent village
沉默的村庄
Listen to the tape then answer the question below.
Why was the village silent?
In this much-travelled world, there are still thousands of places which are inaccessible to tourists. We always assume that villagers in remote places are friendly and hospitable. But people who are cut off not only from foreign tourists, but even from their own countrymen can be hostile to travellers. Visits to really remote villages are seldom enjoyable -- as my wife and I discovered during a tour through the Balkans.
We had spent several days in a small town and visited a number of old churches in the vicinity. These attracted many visitors, for they were not only of great architectural interest, but contained a large number of beautifully preserved frescoes as well. On the day before our departure, several bus loads of tourists descended on the town. This was more than we could bear, so we decided to spend our last day exploring the countryside. Taking a path which led out of the town, we crossed a few fields until we came to a dense wood. We expected the path to end abruptly, but we found that it traced its way through the trees. We tramped through the wood for over two hours until we arrived at a deep stream. We could see that the path continued on the other side, but we had no idea how we could get across the stream. Suddenly my wife spotted a boat moored to the bank. In it there was a boatman fast asleep. We gently woke him up and asked him to ferry us to the other side. Though he was reluctant to do so at first, we eventually persuaded him to take us.
The path led to a tiny village perched on the steep sides of a mountain. The place consisted of a straggling unmade road which was lined on either side by small houses. Even under a clear blue sky, the village looked forbidding, as all the houses were built of grey mud bricks. The village seemed deserted, the only sign of life being an ugly-looking black goat on a short length of rope tied to a tree in a field nearby. Sitting down on a dilapidated wooden fence near the field, we opened a couple of tins of sardines and had a picnic lunch. All at once, I noticed that my wife seemed to be filled with alarm. Looking up I saw that we were surrounded by children in rags who were looking at us silently as we ate. We offered them food and spoke to them kindly, but they remained motionless. I concluded that they were simply shy of strangers. When we later walked down the main street of the villager, we were followed by a silent procession of children. The village which had seemed deserted, immediately came to life. Faces appeared at windows. Men in shirt sleeves stood outside their houses and glared at us. Old women in black shawls peered at us from doorways. The most frightening thing of all was that not a sound could be heard. There was no doubt that we were unwelcome visitors. We needed no further warning. Turning back down the main street, we quickened our pace and made our way rapidly towards the stream where we hoped the boatman was waiting.
New words and expressions 生词和短语
inaccessible
hospitable
hostile
vicinity
n. 周围,近邻
architectural
fresco
n. 壁画
abruptly
tramp
v. 徒步行进
moor
v. （用绳、链、锚）系（船）
ferry
v. （用渡船）运
straggle
v. 蔓延，散乱分布
sardine
n. 沙丁鱼，沙丁鱼罐头
rag
n. 破烂衣服
procession
shawl
n. 披巾，围巾
peer
v. 凝视，盯着
quicken
v. 加快
在这个旅游频繁的世界上，仍有成千上万个游人足迹未至的地方。人们总是以为偏僻的地方的村民们热情好客。但是，那些不但与外国旅游者隔绝，而且与本国同胞隔绝的人们有可能对游客抱有敌意。到真正偏僻的村庄去旅游并不是一件愉快的事情。我与妻子在一次周游巴尔干半岛时对此深有体会。
我们在一座小镇上逗留了几天，参观了附近的许多古老的教堂。这些教堂吸引大量游客，不仅是因为建筑风格奇特，而且还有大量保存完好的壁画。我们离开小镇的前一天，镇上来了几辆满载游客的公共汽车。人多得使我们难以忍受，于是我们决定利用最后一天去乡间一游。我们走上了一条出镇的小路，穿过几块农田，来到一片茂密的树林。我们原以为小路会到此突然终止。没想到它到树林中继续向前延伸。我们在树林中跋涉了两个多小时，到了一条深溪边。我们可以看到小路在深溪对岸继续向前伸展，但却不知如何越过这道深溪。突然，妻子发现岸边泊着一条小船，船上有一船夫在呼呼大睡。我们轻轻地把他唤醒，请他把我们摆渡过溪。一开始，他很不愿意，但经劝说，终于同意了。
顺着小路，我们来到一个座落在陡峭山坡上的小村庄。这儿有一条未经修筑的弯弯曲曲的道路，路两边排列着一些矮小的农舍。农舍全用灰色的土坯建成，因此，即使在晴朗的蓝天底下，村庄看上去也会令人感到难以亲近。村里似乎无人居住，唯一的生命迹象是附近田里一只面目可憎的黑山羊，用一截短绳拴在一棵树上。我们在田边一堵东倒西歪的篱笆墙上坐下来，打开几听沙丁鱼罐头，吃了一顿野外午餐。突然，我注意到妻子十分惊恐。我抬头一看，发现我们被一群衣衫褴褛的小孩团团围住了，他们在默不作声地看着我们吃饭。我们给他们东西吃，客客气气地同他们交谈，但他们却一动也不动。我认为这不过是他们在陌生人面前表现出的害羞。后来，我们在村里的主要街道上行走的时候，一队默不作声的孩子跟在我们后头。刚才还似乎空荡荡的村庄一下子活跃了起来，窗口露出了一张张面孔，只穿着衬衣的男人们站在屋子外面凶狠地盯着我们，披黑纱巾的老妇人站在门口偷偷地瞅着我们。最令人害怕的是到处没有一点声音。毫无疑问，我们的来访是不受欢迎的。我们不需要进一步的警告了。便掉转身子，沿着那条主要街道加快步伐，快速地朝深溪边走去，希望船夫还在那儿等着我们。
Lesson 49
The ideal servant
理想的仆人
Listen to the tape then answer the question below.
It is a good thing my aunt Harriet died years ago. If she were alive today she would not be able to air her views on her favourite topic of conversation: domestic servants. Aunt Harriet lived in that leisurely age when servants were employed to do housework. She had a huge, rambling country house called 'The Gables'. She was sentimentally attached to this house, for even though it was far too big for her needs, she persisted in living there long after her husband's death. Before she grew old, Aunt Harriet used to entertain lavishly. I often visited The Gables when I was boy. No matter how many guests were present, the great house was always immaculate. The parquet floors shone like mirrors; highly polished silver was displayed in gleaming glass cabinets; even my uncle's huge collection of books was kept miraculously free from dust. Aunt Harriet presided over an invisible army of servants that continuously scrubbed, cleaned, and polished. She always referred to them as 'the shifting population', for they came and went with such frequency that I never even got a chance to learn their names. Though my aunt pursued what was, in those days, an enlightened policy, in that she never allowed her domestic staff to work more than eight hours a day, she was extremely difficult to please. While she always criticized the fickleness of human nature, she carried on an unrelenting search for the ideal servant to the end of her days, even after she had been sadly disillusioned by Bessie.
Bessie worked for Aunt Harriet for three years. During that time she so gained my aunt's confidence that she was put in charge of the domestic staff. Aunt Harriet could not find words to praise Bessie's industriousness and efficiency. In addition to all her other qualifications, Bessie was an expert cook. She acted the role of the perfect servant for three years before Aunt Harriet discovered her 'little weakness'. After being absent from the Gables for a week, my aunt unexpectedly returned one afternoon with a party of guests and instructed Bessie to prepare dinner. No only was the meal well below the usual standard, but Bessie seemed unable to walk steadily. She bumped into the furniture and kept mumbling about the guests. When she came in with the last course -- a huge pudding -- she tripped on the carpet and the pudding went flying through the air, narrowly missed my aunt, and crashed on the dining table with considerable force. Though this caused great mirth among the guests, Aunt Harriet was horrified. She reluctantly came to the conclusion that Bessie was drunk. The guests had, of course, realized this from the moment Bessie opened the door for them and, long before the final catastrophe, had had a difficult time trying to conceal their amusement. The poor girl was dismissed instantly. After her departure, Aunt Harriet discovered that there were piles of empty wine bottles of all shapes and sizes neatly stacked in what had once been Bessie's wardrobe. They had mysteriously found their way there from the wine cellar!
New words and expressions 生词和短语
rambling
sentimentally
immaculate
lavishly
parquet
n. 镶木地板
gleam
v. 发亮，闪光
preside
v. 指挥
invisible
scrub
v. 擦拭，刷洗
enlightened
fickleness
n. 变化无常
unrelenting
disillusion
v. 使幻想破灭的
qualification
n. 资格，能力
mirth
n. 欢笑，高兴
stack
v. 整齐地堆放
cellar
n. 地窖
我的姑妈哈丽特好多年前就去世了，这倒是件好事。如果她活到今天，她将不能就她热衷的话题“佣人”发表意见了。哈丽特生活在一个悠闲的年代，家务事都由雇来的佣人代劳。她在乡下有一幢巨大杂乱的房子，叫作“山墙庄园”。她对这幢房子在感情上难舍难分。房子实在太大了，但在丈夫去世多年后，她仍然执意长年住在那儿。哈丽特姑妈年轻时，喜欢大摆宴席，招待宾客。我小时候常去“山墙庄园”作客。不管去多少宾客，大房子里总是收拾得干干净净。镶木地板洁如明镜，擦得发亮的银器陈列在明亮的玻璃柜里，连姑夫的大量藏书也保存得很好，奇迹般地一尘不染。哈丽特姑妈统率着一支看不见的佣人大军，他们不停地擦拭、清扫、刷洗。她称这些佣人叫“流动人口”，因为他们来匆匆，所以我甚至都没有机会知道他们的姓名。姑妈待佣人在当时算是开明的，从来不让佣人每天工作超过8小时，但他们很难使她称心如意。她一方面总是批评人的本性朝三暮四，另一方面她又持之以恒地寻找一个理想的佣人。即使在贝西大大地伤她的心之后，她还在找，一直到她死去。
贝西在哈丽特家干了3年。在此期间，她赢得了姑母的赏识，甚至当上了大管家。哈丽特不知该用什么言辞来赞扬贝西的勤奋与高效。贝西除了有各种本领以外，还是一个烹饪大师。她担任“理想仆人”角色3年之后，哈丽特终于发现她有“小小的弱点”。一次，姑妈有一个星期没在“山墙庄园”住。一天下午，她出其不意地回来了，带来一大批客人，吩咐贝西准备晚饭。结果，不仅饭菜远不如平时做得好，而且贝西走起路来似乎东倒西歪。她撞到了家具上，嘴里还不断咕咕哝哝议论客人。当她端着最后一道菜——一大盘布丁——走进屋来时，在地毯上绊了一跤。布丁飞到半空，从姑母身边擦过，然后狠狠地砸在餐桌上。这件事引起了客人们的欢笑，但哈丽特却着实吓了一跳。她不得不认定贝西是喝醉了。客人们自然从贝西为他们开门那一刻起就看出来了，在好长一段时间里，即最后这个乱子发生前，他们努力克制才没笑出声来。贝西当即被解雇了。贝西走后，哈丽特姑妈发现在贝西以前用过的衣柜里整整齐齐地放着一堆堆形状各导、大小不一的酒瓶子。这些酒瓶神不知鬼不觉地从酒窖来到了这里。
Lesson 50
New Year resolutions
新年的决心
Listen to the tape then answer the question below.
What marked the end of the writer's New Year resolutions?
The New Year is a time for resolutions. Mentally, at least, most of us could compile formidable lists of 'dos' and 'don'ts'. The same old favorites recur year in year out with monotonous regularity. We resolve to get up earlier each morning, eat less, find more time to play with the children, do a thousand and one jobs about the house, be nice to people we don't' like, drive carefully, and take the dog for a walk every day. Past experience has taught us that certain accomplishments are beyond attainment. If we remain inveterate smokers, it is only because we have so often experienced the frustration that results from failure. Most of us fail in our efforts at self-improvement because our schemes are too ambitious and we never have time to carry them out. We also make the fundamental error of announcing our resolutions to everybody so that we look even more foolish when we slip back into our bad old ways. Aware of these pitfalls, this year I attempted to keep my resolutions to myself. I limited myself to two modest ambitions: to do physical exercise every morning and to read more of an evening. An all-night party on New Year's Eve provided me with a good excuse for not carrying out either of these new resolutions on the first day of the year, but on the second, I applied myself assiduously to the task.
New words and expressions 生词和短语
resolution
n. 决心
mentally
compile
v. 编辑，编制
formidable
recur
v. 再发生，又出现
regularity
n. 规律性
accomplishment
n. 成就
attainment
n. 达到
inveterate
self-improvement
n. 自我完善
scheme
n. 简单的计划，方案
ambitious
pitfall
n. 意外的困难，易犯的错误
modest
assiduously
self-discipline
n. 自我约束
frame
n. 躯体
betray
v. 暴露，显露
troop
v. 成群结队地走动
unsettle
v. 使不安
taunt
n. 嘲笑，奚落人的话
jibe
n. 嘲弄，挖苦
good-humouredly
wane
v. 逐渐变小，变弱
hypnotize
v. 使欲睡，使蒙胧
undoing
n. 祸根，毁灭的原因
screen
n. 电视机屏幕
新年是下决心的时候，至少在大多数人的心里会编排出一份“应做什么”和“不应做什么”的令人生畏的单子。相同的决心以单调的规律年复一年地出现。我们决心每天早晨起得早些；吃得少些；多花点时间与孩子们一起做游戏；做大量的家务；对不喜欢的人友善一些；小心驾车；每天都要带着狗散步；等等。以往的经验告诉我们有些事是办不到的。如果我们烟瘾大，戒不掉，那是因为屡戒屡败，失去信心。我们大多数人想自我完善却遭到失败，这是因为我们的规划过于宏大，而又根本没有时间去实施。我们还犯有一个根本性的错误，即把我们的决心向大家宣布。这样一旦滑回到那些老习惯上去，我们在别人的眼里会显得更加难堪。我深知这些问题，于是，今年我对自己的计划要严加保密，只给自己定下两项适中的任务；每天早上锻炼身体，每天晚上多看点书。新年除夕举办的一次通宵晚会，使我理直气壮地在新年头一天免去了这两项任务。不过，新年第二天，我全力以赴地照着去做了。
早锻炼一共只有11分钟，我打算在别人起床之前进行。这就要求我比平时早11分钟把自己从床上拽起来，这种自我约束是很艰苦的。不过开头两天我还是成功地蹑手蹑脚地来到楼下起居室，被谁也没发现。我在地毯上跳来蹦过去，扭曲身子，摆出各种姿势，弄得浑身不舒服，然后坐到桌边吃早饭，一副筋疲力尽的样子。正是这副模样泄露了我的秘密。第二天早晨全家人结队来到起居室看我表演。这真叫人不好意思，但我心平气和地顶住全家人的嘲笑和奚落。不久，大家对我习以为常了，而这时我的热情却减退了。我花在锻炼上的时间逐渐减少，慢慢地从11分钟减到了零。到了1月10日，我恢复了原来的作息时间。我辩解说，早晨少耗费精力锻炼，晚上下班回家看书时头脑更清醒些。有几天晚上，我极力摆脱了电视的诱惑，坐在自己的房间里，两眼盯在书上。可是，有一天夜里，我感到又冷又孤单，便来到楼下坐在电视机前假装看书。这下我可完了，因为不一会儿，我就恢复了以前的坏习惯，在屏幕前打起瞌睡来。但我还没有放弃多看些书的决心。事实上，我刚买来一本叫《一分钟读一千字的诀窍》的书。也许这本书能解决我的问题，但我一直还没时间去看这本书！
Lesson 51
Predicting the future
预测未来
Listen to the tape then answer the question below.
What was the 'future' electronic development that Leon Bagrit wasn't able to foresee?
Predicting the future is notoriously difficult. Who could have imagined, in the mid 1970s, for example, that by the end of the 20th century, computers would be as common in people's homes as TV sets? In the 1970s, computers were common enough, but only in big business, government departments, and large organizations. These were the so-called mainframe machines. Mainframe computers were very large indeed, often occupying whole air-conditioned rooms, employing full-time technicians and run on specially-written software. Though these large machines still exist, many of their functions have been taken over by small powerful personal computers, commonly known as PCs.
In 1975, a primitive machine called the Altair, was launched in the USA. It can properly be described as the first 'home computer' and it pointed the way to the future. This was followed, at the end of the 1970s, by a machine called an Apple. In the early 1980s, the computer giant, IBM produced the world's first Personal Computer. This ran on an 'operating system' called DOS, produced by a then small company named Microsoft. The IBM Personal Computer was widely copied. From those humble beginnings, we have seen the development of the user-friendly home computers and multimedia machines which are in common use today.
Considering how recent these developments are, it is even more remarkable that as long ago as the 1960s, an Englishman, Leon Bagrit, was able to predict some of the uses of computers which we know today. Bagrit dismissed the idea that computers would learn to 'think' for themselves and would 'rule the world', which people liked to believe in those days. Bagrit foresaw a time when computers would be small enough to hold in the hand, when they would be capable of providing information about traffic jams and suggesting alternative routes, when they would be used in hospitals to help doctors to diagnose illnesses, when they would relieve office workers and accountants of dull, repetitive clerical work. All these computer uses have become commonplace. Of course, Leon Bagrit could not possibly have foreseen the development of the Internet, the worldwide system that enables us to communicate instantly with anyone in any part of the world by using computers linked to telephone networks. Nor could he have foreseen how we could use the Internet to obtain information on every known subject, so we can read it on a screen in our homes and even print it as well if we want to. Computers have become smaller and smaller, more and more powerful and cheaper and cheaper. This is what makes Leon Bagrit's predictions particularly remarkable. If he, or someone like him, were alive today, he might be able to tell us what to expect in the next fifty years.
New words and expressions 生词和短语
notoriously
full-time
technician
n. 技师
software
n. 软件
IBM
DOS
磁盘操作系统（Disk Operating System）
Microsoft
n. （美国）微软公司
user-friendly
mainframe
n. 主机，中央处理机
multimedia
alternative
diagnose
v. 诊断
relieve
v. 减轻
accountant
n. 会计
repetitive
clerical
Internet
n. 国际交互网
network
n. 网络
众所周知，预测未来是非常困难的。举个例子吧，在20世纪70年代中叶又有谁能想得到在20世纪末的时候，家庭用的计算机会像电视机一样普遍？在70年代，计算机已经相当普及了，但只用在大公司，政府部门和大的组织之中，它们被称为主机。计算机主机确实很大，常常占据了装有空调的多间房间，雇用专职的技师，而且得用专门编写的软件才能运行。虽然这种大计算机仍然存在，但它们的许多功能已被体积小但功能齐全的个人电脑——即我们常说的PC机——所代替了。
1975年，美国推出了一台被称为“牛郎星”的原始机型。严格地说起来，它可以被称为第一台“家用电脑”，而且它也指了今后的方向。70年代末，在牛郎星之后又出现了一种被称为“苹果”的机型。80年代初，计算机行业的王牌公司美国国际商用机器公司（IBM）生产出了世界上第一台个人电脑。这种电脑采用了一种被称为磁盘操作系统（DOS）的工作程序，而这种程序是由当时规模不大的微软公司生产的。IBM的个人电脑被大规模地模仿。从那些简陋的初级阶段，我们看到了现在都已普及的、使用简便的家用电脑和多媒体的微机的发展。
想一想这些发展的时间多么短，就更觉得英国人莱昂.巴格瑞特有着非凡的能力。他在60年代就能预言我们今天知道的计算机的一些用途。巴格瑞特根本不接受计算机可以学会自己去“思考”和计算可以“统治世界”这种想法，而这种想法是当时的人们都愿意相信的。巴格瑞特预示有一天计算机可以小到拿在手上，计算机可以使办公室人员和会计免除那些枯燥、重复的劳动。计算机的所有这些功能现在都变得很平常。当然了，莱昂.巴格瑞特根本没有可能预测到国际交互网——就是把计算机连结到电话线路上，以便和世界上任何一个地方的人立即进行联系的一个世界范围的通讯系统——的发展。他也无法预测到我们可以利用国际交互网获取有关任何已知专题的信息，以便在家里的屏幕上阅读，如果愿意的话甚至可以将其打印出来。计算机已经变得体积越来越小，功能越来越多，价格越来越低，这就是莱昂.巴格瑞特的预测非凡的地方。如果他或是像他的什么人今天还活着的话，他大概可以告诉我们下一个50年后会发生什么事情。
Lesson 52
Mud is mud
实事求是
Listen to the tape then answer the question below.
Why did Harry decide to give up his little game?
My cousin, Harry, keeps a large curiously-shaped bottle on permanent display in his study. Despite the fact that the bottle is tinted a delicate shade of green, an observant visitor would soon notice that it is filled with what looks like a thick, grayish substance. If you were to ask Harry what was in the bottle, he would tell you that it contained perfumed mud. If you expressed doubt or surprise, he would immediately invite you to smell it and then to rub some into your skin. This brief experiment would dispel any further doubts you might have. The bottle really does contain perfumed mud. How Harry came into the possession of this outlandish stuff makes an interesting story which he is fond of relating. Furthermore, the acquisition of this bottle cured him of a bad habit he had been developing for years.
Harry used to consider it a great joke to go into expensive cosmetic shops and make outrageous requests for goods that do not exist. He would invent fanciful names on the spot. On entering a shop, he would ask for a new perfume called 'Scented Shadow' or for 'insoluble bath cubes'. If a shop assistant told him she had not heard of it, he would pretend to be considerably put out. He loved to be told that one of his imaginary products was temporarily out of stock and he would faithfully promise to call again at some future date, but of course he never did. How Harry managed to keep a straight face during these performances is quite beyond me.
Harry does not need to be prompted to explain how he bought his precious bottle of mud. One day, he went to an exclusive shop in London and asked for 'Myrolite', the shop assistant looked puzzled and Harry repeated the word, slowly stressing each syllable. When the woman shook her head in bewilderment, Harry went on to explain that 'myrolite' was a hard, amber-like substance which could be used to remove freckles. This explanation evidently conveyed something to the woman who searched shelf after shelf. She produced all sorts of weird concoctions, but none of them met with Harry's requirements. When Harry put on his act of being mildly annoyed, the assistant promised to order some for him. Intoxicated by his success, Harry then asked for perfumed mud. He expected the assistant to look at him in blank astonishment. However, it was his turn to be surprised, for the woman's eyes immediately lit up and she fetched several bottles which she placed on the counter for Harry to inspect. For once, Harry had to admit defeat. He picked up what seemed to be the smallest bottle and discreetly asked the price. He was glad to get away with a mere twenty pounds and he beat a hasty retreat, clutching the precious bottle under his arm. From then on, Harry decided that this little game he had invented might prove to be expensive. The curious bottle, which now adorns the bookcase in his study, was his first and last purchase of rare cosmetics.
New words and expressions 生词和短语
permanent
tint
v. 给……染色
delicate
n. 色度
observant
dispel
v. 驱散，消除
outlandish
acquisition
n. 获得
cosmetic
n. 化妆品
outrageous
fanciful
insoluble
prompt
v. 敦促，激励
exclusive
syllable
n. 音节
bewilderment
n. 迷惑，糊涂
freckle
n. 雀斑
evidently
weird
concoction
n. 调制品
intoxicate
v. 陶醉，得意忘形
blank
discreetly
clutch
v. 抓住
v. 装饰，打扮
我的堂兄哈里在他的书房里一直摆着一只形状古怪的大瓶子。尽管那只瓶子呈淡绿色，但细心的客人很快就会发现瓶里装的是一种看上去黏稠，颜色发灰的东西。要是你问哈里瓶里装着什么，他会告诉你是香水泥。如果你表示怀疑或惊奇，他会立即请你闻一闻，然后取出一些抹在你的皮肤上。这一简单的试验会消除你可能存有的一切疑虑。瓶里装的的确是香水泥。哈里如何得到这种稀奇古怪的东西的，这里有个有趣的故事，而且他挺爱把它讲给别人听。此外，得到这瓶香水泥还治好了他多年的一个坏习惯。
哈里曾认为走进一家名贵化妆品商店，荒唐地提出要买一种根本不存在的商品是件开心的事儿。他会当场编造出一些稀奇古怪的货名。他走进商店后，会提出要一种名叫“香影”的新型香水或什么“不溶浴皂”。要是女售货员告诉他从未听说过这些东西，他会装出十分遗憾和不安的样子。他爱听售货员说他想像出来的那种东西暂时脱销，于是他就煞有介事地许诺改天再来光顾。当然，他再也不会来了。我实在想像不出哈里在这些表演中是怎样装出一本正经的样子的。
毋须暗示哈里就会向你讲起他买下那瓶珍贵香水泥的经过。一天，他去伦敦一家高级商店要买一种叫“密诺莱特”的东西，店员露出诧异的神色。哈里又慢慢地，一字一顿说了一遍这个词，那个女售货员还是迷惑不解地摇了摇头。哈里便进一步解释“密诺莱特”是一种质地坚硬、状似琥珀的东西，可以用来除去雀斑。他的解释显然对女售货员有些启示。她一个货架接着一个货架地寻找，拿出各种各样稀奇古怪的化妆品，但没有一样能够符合哈里的要求。哈里装出不高兴的样子时，女售货员答应为他定货。哈里为他的骗术而感到洋洋得意，又提出要买香水泥。他原想女售货员会惊奇地望着他，不知所措，没料到这回该轮到他自己吃惊了。因为那女售货员听完哈里的话后，马上眼睛一亮，拿出几瓶东西放在柜台上让哈里挑选。哈里只好认输。他挑出一个看上去最小的瓶子，谨慎地问了价。他庆幸自己只破费了20英镑便得以脱身。他把那宝贵的瓶子放在腋下夹着，溜之大吉。从那以后，他认识到自己发明的小小恶作剧是要付出很大的代价的。在他书房的书柜里摆着那瓶形状古怪的香水泥就是他第一次也是最后一次购买的稀有化妆品。
Lesson 53
In the public interest
为了公众的利益
Listen to the tape then answer the question below.
What could not be reported in the official flees?
The Scandinavian countries are much admired all over the world for their enlightened social policies. Sweden has evolved an excellent system for protecting the individual citizen from highhanded or incompetent public officers. The system has worked so well, that it has been adopted in other countries too.
The Swedes were the first to recognize that public official like civil servants, police officers, health inspectors or tax-collectors can make mistakes or act over-zealously in the belief that they are serving the public. As long ago as 1809, the Swedish Parliament introduced a scheme to safeguard the interest of the individual. A parliamentary committee representing all political parties appoints a person who is suitably qualified to investigate private grievances against the State. The official title of the person is 'Justiteombudsman', but the Swedes commonly refer to him as the 'J.O.' or 'Ombudsman'. The Ombudsman is not subject to political pressure. He investigates complaints large and small that come to him from all levels of society. As complaints must be made in writing, the Ombudsman receives an average of 1,200 letters a year. He has eight lawyer assistants to help him and examines every single letter in detail. There is nothing secretive about the Ombudsman's work for his correspondence is open to public inspection. If a citizen's complaint is justified, the Ombudsman will act on his behalf. The action he takes varies according to the nature of the complaint. He may gently reprimand an official or even suggest to parliament that a law the altered. The following case is a typical example of the Ombudsman's work.
A foreigner living in a Swedish village wrote to the Ombudsman complaining that he had been ill-treated by the police, simply because he was a foreigner. The Ombudsman immediately wrote to the Chief of Police in the district asking him to send a record of the case. There was nothing in the record to show that the foreigner's complaint was justified and the Chief of Police strongly denied the accusation. It was impossible for the Ombudsman to take action, but when he received a similar complaint from another foreigner in the same village, he immediately sent one of his layers to investigate the matter. The lawyer ascertained that a policeman had indeed dealt roughly with foreigners on several occasions. The fact that the policeman was prejudiced against foreigners could not be recorded in the official files. It was only possible for the Ombudsman to find this out by sending one of his representatives to check the facts. The policeman in question was severely reprimanded and was informed that if any further complaints were lodged against him, he would prosecuted. The Ombudsman's prompt action at once put an end to an unpleasant practice which might have gone unnoticed.
New words and expressions 生词和短语
evolve
v. 逐渐形成
high-handed
incompetent
over-zealously
safeguard
v. 保护
parliamentary
qalified
grievance
n. 不平，冤屈
Justiteombudsman
n. （瑞典的）司法特派员
ombudsman
n. （瑞典和英国的）司法特派员
secretive
correspondence
n. 来往信件
alter
v. 改变
accusation
n. 谴责，指控
ascertain
v. 查出，查明
prejudiced
prompt
斯堪的纳维亚半岛各国实行开明的社会政策，受到全世界的推崇。在瑞典，已逐渐形成了一种完善的制度以保护每个公民不受专横的和不称职的政府官员的欺压。由于这种制度行之有效，已被其他国家采纳。
是瑞典人首先认识到政府工作人员如文职人员、警官、卫生稽查员、税务人员等等也会犯错误或者自以为在为公众服务而把事情做过了头。早在1809年，瑞典论会就建立一个保护公民利益的制度。议会内有一个代表各政党利益的委员会，由它委派一位称职的人选专门调查个人对国家的意见。此人官衔为“司法特派员”，但瑞典人一般管他叫“J.O.”，即“司法特派员”。司法特派员不受任何政治压力的制约。他听取社会各阶层的各种大小意见，并进行调查。由于意见均需用书面形式提出，司法特派员每年平均收到1,200封信。他有8位律师作他的助手协助工作，每封信都详细批阅。司法特派员的工作没有什么秘密可言，他的信件是公开的，供公众监督。如果公民的意见正确，司法特派员便为他伸张正义。司法特员采取的行动因意见的性质不同而有所不同。他可以善意地批评某位官员，也可以甚至向议会提议修改某项法律。下述事件是司法特派员工作的一个典型例子。
一个住在瑞典乡村的外国人写信给司法特派员，抱怨说他受到警察的虐待，原因就是因为他是个外国人。司法特派员立即写信给当地警察局长，请他寄送与此事有关的材料。材料中没有任何文字记载证明外国人所说的情况符合事实，警察局长矢口否认这一指控。司法特派员难以处理。但是，当他又收到住在同一村庄的另一个外国人写的一封内容类似的投诉信时，他立即派出一位律师前去调查。律师证实有个警察确实多次粗鲁地对待外国人。警察歧视外国人的事在官方档案中不可能加以记载，司法特派员只有派他的代表去核对事实才能了解真相。当事的警察受到严厉的斥责，并被告知，如果再有人投诉他，他将受到起诉。司法特派员及时采取的行动，迅速制止了这一起不愉快的事件，不然这件事可能因未得到人们注意而不了了之。
Lesson 54
Instinct or cleverness?
是本能还是机智
Listen to the tape then answer the question below.
Was the writer successful in protecting his peach tree? Why not?
Last summer I spent days in the garden watching thousands of ants crawling up the trunk of my prize peach tree. The tree has grown against a warm wall on a sheltered side of the house. I am especially proud of it, not only because it has survived several severe winters, but because it occasionally produces luscious peaches. During the summer, I noticed tat the leaves of the tree were beginning to wither. Clusters of tin insects called aphids were to be found on the underside of the leaves. They were visited by a large colony of ants which obtained a sort of honey from them. I immediately embarked on an experiment which, even though if failed to get rid of the ants, kept me fascinated for twenty-four hours. I bound the base of the tree with sticky tape, making it impossible for the ants to reach the aphids. The tape was so stick that they did not dare to cross it. For a long time. I watched them scurrying around the base of the tree in bewilderment. I even went out at midnight with a torch and noted with satisfaction (and surprise) that the ants were still swarming around the sticky tape without being able to do anything about it. I got up early next morning hoping to find that the ants had given up in despair. Instead, I saw that they had discovered a new route. They were climbing up the wall of the house and then on to the leaves of the tree. I realized sadly that I had been completely defeated by their ingenuity. The ants had been quick to find an answer to my thoroughly unscientific methods!
New words and expressions 生词和短语
insect
n. 昆虫
wage
v. 进行（斗争）
contaminate
v. 弄脏
provocation
n. 惹怒
spider
n. 蜘蛛
wasp
n. 黄蜂
moth
n. 飞蛾
ant
n. 蚂蚁
revulsion
n. 厌恶
horde
n. 群
uncanny
erase
v. 擦，抹去
praying mantis
螳螂
entranced
beetle
n. 甲虫
sheltered
luscious
cluster
n. 一簇
aphid
n. 蚜虫
underside
n. 底面，下侧
colony
n. 一群
sticky
scurry
v. 小步跑
swarm
v. 聚集
ingenuity
n. 机灵
我们自幼就在对昆虫的惧怕中长大。我们把昆虫当作害多益少的无用东西。人类不断同昆虫斗争，因为昆虫弄脏我们的食物，传播疾病，吞噬庄稼。它们无缘无故地又叮又咬；夏天的晚上，它们未经邀请便飞到我们房间里，或者对着露出亮光的窗户乱扑乱撞。我们在日常生活中，不但憎恶如蜘蛛、黄蜂之类令人讨厌的昆虫，而且憎恶并无大害的飞蛾等。阅读有关昆虫的书能增加我们对它们的了解，却不能消除我们的恐惧的心理。即使知道勤奋的蚂蚁生活具有高度组织性的社会里，当看到大群蚂蚁在我们精心准备的午间野餐上爬行时，我们也无法抑制对它们的反感。不管我们多么爱吃蜂蜜，或读过多少关于蜜蜂具有神秘的识别方向的灵感的书，我们仍然十分害怕被蜂蜇。我们的恐惧大部分是没有道理的，但去无法消除。同时，不知为什么昆虫又是迷人的。我们喜欢看有关昆虫的书，尤其是当我们了解螳螂等过着一种令人生畏的生活时，就更加爱读有关昆虫的书了。我们喜欢入迷地看它们做事，它们不知道（但愿如此）我们就在它们身边。当看到蜘蛛扑向一只苍蝇时，一队蚂蚁抬着一只巨大的死甲虫凯旋归时，谁能不感到敬畏呢？
去年夏天，我花了好几天时间站在花园里观察成千只蚂蚁爬上我那棵心爱的桃树的树干。那棵树是靠着房子有遮挡的一面暖墙生长的。我为这棵树感到特别自豪，不仅因为它度过了几个寒冬终于活了下来，而且还因为它有时结出些甘甜的桃子来。到了夏天，我发现树叶开始枯萎，结果在树叶背面找到成串的叫作蚜虫小虫子。蚜虫遭到一窝蚂蚁的攻击，蚂蚁从它们身上可以获得一种蜜。我当即动手作了一项试验，这项试验尽管没有使我摆脱这些蚂蚁，却使我着迷了24小时。我用一条胶带把桃树底部包上，不让蚂蚁接近蚜虫。胶带极粘，蚂蚁不敢从上面爬过。在很长一段时间里，我看见蚂蚁围着大树底部来回转悠，不知所措。半夜，我还拿着电筒来到花园里，满意地（同时惊奇地）发现那些蚂蚁还围着胶带团团转。无能为力。第二天早上，我起床后希望看见蚂蚁已因无望而放弃了尝试，结果却发现它们又找到一条新的路径。它们正在顺着房子的外墙往上爬，然后爬上树叶。我懊丧地感到败在了足智多谋的蚂蚁的手下。蚂蚁已很快找到了相应的对策，来对付我那套完全不科学的办法！
Lesson 55
From the earth: Greetings
来自地球的问候
Listen to the tape then answer the question below.
Which life forms are most likely to develop on a distant planet?
Recent developments in astronomy have made it possible to detect planets in our won Milky Way and in other galaxies. This is a major achievement because, in relative terms, planets are very small and old not emit light. Finding planets is proving hard enough, but finding life on them will prove infinitely more difficult. The first question to answer is whether a planet can actually support life. In our won solar system, for example, Venus is far too hot and Mars is far too cold to support life. Only the Earth provides ideal conditions, and even here it has taken more than four billion years for plant and animal life to evolve.
Whether a planet can support life depends on the size and brightness of its star, that is its 'sun'. Imagine a star up t twenty times larger, brighter, brighter and hotter than our own sun. A planet would have to be a very long way from it to be capable of supporting life. Alternatively, if the star were small, the life-supporting planet would have to have a close orbit round it and also provide the perfect conditions for life forms to develop. But how would we find such a planet? At present, there is no telescope in existence that is capable of detecting the presence of life. The development of such a telescope will be one of the great astronomical projects of the twenty-first century.
It is impossible to look for life on another planet using earth-based telescopes. Our own warm atmosphere and the heat generated by the telescope would make it impossible to detect objects as small as planets. Even a telescope in orbit round the earth, like the very successful Hubble telescope, would not be suitable because of the dust particles iron solar system. A telescope would have to be as far away as the planet Jupiter to look for life in outer space, because the dust becomes thinner the further we travel towards the outer edges of our own solar system. Once we detected a planet, we would have to find a way of blotting out the light from its star, so that we would be able to 'see' the planet properly and analyze its atmosphere. In the first instance, we would be looking for plant life, rather than 'little green men'. The life forms most likely to develop on a planet would be bacteria. It is bacteria that have generated the oxygen we breathe on earth. For most of the earth's history they have been the only form of life on our planet. As Earth-dwellers, we always cherish the hope that we will be visited by little green men and that we will be able to communicate with them. But this hope is always in the realms of science fiction. If we were able to discover lowly forms of life like bacteria on another planet, it would completely change our view of ourselves. As Daniel Goldin of NASA observed, 'Finding life elsewhere would change everything. No human endeavor or thought would be unchanged by it."
New words and expressions 生词和短语
astronomy
n. 天文学
relative
infinitely
solar
Venus
n. 金星
Mars
n. 火星
orbit
n. 运行轨道
astronomical
generate
v. 产生
particle
n. 微粒，粒子
Jupiter
n. 木星
blot
v. 遮暗
analyse
v. 分析
bacteria
n. 细菌
oxygen
n. 氧气
realm
n. 领域
endeavour
v. 努力
天文学方面最新发展使得我们能够在银河系和其他星系发现行星。这是一个重要的成就，因为相对来说，行星很小，而且也不发光。寻找行星证明相当困难，但是要在行星上发现生命会变得无比艰难。第一个需要解答的问题是一颗行星是否有能够维持生命的条件。举例来说，在我们的太阳系里，对于生命来说，金星的温度太高，而火星的温度则太低。只有地球提供理想的条件，而即使在这里，植物和动物的进化也用了40亿年的时间。
一颗行星是否能够维持生命取决于它的恒星——即它的“太阳”——的大小和亮度。设想一下，一颗恒星比我们的太阳还要大，还要亮，还要热20倍，那么一颗行星为了维持生命就要离开的它的恒星非常远。反之，如果恒星很小，维持生命的行星就要在离恒星很近的轨道上运行，而且要有极好的条件才能使生命得以发展，但是，我们如何才能找到这样一颗行星呢？现在，没有一台现存的望远镜可以发现生命的存在。而开发这样一台望远镜将会是21世纪天文学的一个重要的研究课题。
使用放置在地球上的望远镜是无法观察到其他行星的生命的。地球周围温暖的大气层和望远镜散出的热量使得我们根本不可能找到比行星更小的物体。即使是一台放置在围绕地球的轨道上的望远镜——如非常成功的哈勃望远镜——也因为太阳系中的尘埃微粒而无法胜任。望远镜要放置在木星那样遥远的行星上才有可能在外层空间搜寻生命。因为我们越是接近太阳系的边缘，尘埃就越稀薄。一旦我们找到这样一颗行星，我们就要想办法将它的恒星射过来的光线遮暗，这样我们就能彻底“看见”这颗行星，并分析它的大气层。首先我们要寻找植物，而不是那种“小绿人”。行星上最容易生存下来的是细菌。正是细菌生产出我们在地球上呼吸的氧气。在地球上发展的大部分进程中，细菌是地球上唯一的生命形式。作为地球上的居民，我们总存有这样的希望：小绿人来拜访我们，而我们可以和他们交流。但是，这种希望总是只在科幻小说中存在。如果我们能够在另一颗行星上找到诸如细菌的那种低等生命，那么这个发现将彻底改变我们对我们自己的看法。正如美国国家航空和宇宙航空局的丹尼尔.戈尔丁指出的“在其他地方发现生命会改变一切。任何人类的努力和想法都会发生变化。”
Lesson 47
Our neighbour, the river
河流，我们的邻居
Listen to the tape then answer the question below.
Why had the neighbours left their farm?
The river which forms the eastern boundary of our farm has always played an important part in our lives. Without it we could not make a living. There is only enough spring water to supply the needs of the houses, so we have to pump from the river for farm use. We tell river all our secrets. We know instinctively, just as beekeepers with their bees, that misfortune might overtake us if the important events of our lives were not related to it.
We have special river birthday parties in the summer. Sometimes were go upstream to a favourite backwater, sometimes we have our party at the boathouse, which a predecessor of ours at the farm built in the meadow hard by the deepest pool for swimming and diving. In a heat wave we choose a midnight birthday party and that is the most exciting of all. We welcome the seasons by the riverside, crowning the youngest girl with flowers in the spring, holding a summer festival on Midsummer Eve, giving thanks for the harvest in the autumn, and throwing a holy wreath into the current in the winter.
After a long period of rain the river may overflow its banks. This is a rare occurrence as our climate seldom guest to extremes. We are lucky in that only the lower fields, which make up a very small proportion of our farm, are effected by flooding, but other farms are less favorably sited, and flooding can sometimes spell disaster for their owners.
One had winter we watched the river creep up the lower meadows. All the cattle had been moved into stalls and we stood to lose little. We were, however, worried about our nearest neighbors, whose farm was low lying and who were newcomers to the district. As the floods had put the telephone out of order, we could not find out how they were managing. From an attic window we could get a sweeping view of the river where their land joined ours, and at the most critical juncture we took turns in watching that point. The first sign of disaster was a dead sheep floating down. Next came a horse, swimming bravely, but we were afraid that the strength of the current would prevent its landing anywhere before it became exhausted. Suddenly a raft appeared, looking rather like Noah's ark, carrying the whole family, a few hens, the dogs, cat, and bird in a cage. We realized that they must have become unduly frightened by the rising flood, for their house, which had sound foundations, would have stood stoutly even if it had been almost submerged. The men of our family waded down through our flooded meadows with boathooks, in the hope of being able to grapple a corner of the raft and pull it out of the current towards our bank. We still think it a miracle that they we able to do so.
New words and expressions 生词和短语
boundary
n. 界线；边界
pump
v. 用泵抽
overtake
v. 突然降临
backwater
n. 回水河汊
predecessor
n. 前任，前辈
n. 草地，草场
crown
v. 给……戴花环
holly
n. 一种冬青植物
wreath
n. 花环
occurrence
n. 偶发事件
proportion
n. 部分
site
v. 使位于
spell
v. 招致，带来
stall
n. 牲口棚
attic
n. 顶楼
sweeping
critical
juncture
n. 时刻，关头
raft
n. 木筏
unduly
foundations
n. 地基
stoutly
submerge
v. 浸没
grapple
v. 抓住
形成我们农场东部边界的一条河流一直在我们生活中发挥着重要作用。要是没有这条河，我们就无法生存下去。泉水只能满足家庭生活用水，因此我们必须从河里抽水以用于农业生产。我们向那条河倾诉我们的秘密。我们本能地懂得，就像养蜂人和他的蜜蜂那样，要是我们不把生活中的重大的事件告诉那条河，就可能大祸临头。
夏天，我们为这条河举办特殊的生日宴会。有时，我们溯流而上来到我们喜爱的回水河汊举办；有时在船坞举办。那船坞是农场一位前辈在一块草地上盖的，草地紧挨着一个专供游泳、跳水的深水池。天气炎热时，我们便选择在半夜举办生日聚会，这种聚会是最令人激动的。我们在河边迎接一年四季。春天在河边为最年轻的姑娘戴上花冠，夏天在河边欢庆“仲夏前夜”，秋天在河边丰收而感恩，冬天往河中抛撒一个冬表花环。
久雨这后，河水会泛滥成灾，但是在我们这里，气候很少发生异常，河水极少泛滥。值得庆幸的是，只有低洼的受到洪水影响，而低洼地在我们农场比例很小。其他农场地势欠佳，洪水有时会给农场主带来灾难。
有一年冬天，天气不好，我们眼看着河水浸没了地势较低的草场。所有的牲口已提前转移到畜圈里，没有造成什么损失。不过，我们很为我们的近邻担心。他们的农场地势低洼，而且他们又新来乍到。由于洪水造成了电话中断，我们无法了解他们情况。从顶楼窗口看去，我们农场与他们农场接壤处的那段河流一览无余。在最紧急的时刻，我们轮流监视那段河流的险情。灾难的第一迹象是一只死羊顺流而下，接着一匹活马勇敢地与水搏击。但我们担心，洪水力量将使它上岸之前就筋疲力尽了。突然，出现了一只筏子，看起来很像诺亚方舟，上面载着他们全家老小，还有几只母鸡、几只狗，一只猫与一只鸟笼，那里头有一只小鸟。我们意识到他们一定是被不断上涨的洪水吓坏了。因为他们的房子地基牢固，即使洪水几乎灭顶也不会倒塌。我家的男人们手拿船篙过被水淹没草场，希望能够钩住筏子一角，将它拽出激流，拖回岸边。他们终于成功了。至今我们仍认为这是个奇迹。
Lesson 57
Back in the old country
重返故里
Listen to the tape then answer the question below.
Did the narrator find is mother's grave?
I stopped to let the car cool off and to study the map. I had expected to be near my objective by now, but everything still seemed alien to me. I was only five when my father had taken me abroad, and that we eighteen years ago. When my mother had died after a tragic accident, he did not quickly recover from the shock and loneliness. Everything around him was full of her presence, continually reopening the wound. So he decided to emigrate. In the new country he became absorbed in making a new life for the two of us, so that he gradually ceased to grieve. He did not marry again and I was brought up without a woman's care; but I lacked for nothing, for he was both father and mother to me. He always meant to go back on day, but not to stay. His roots and mine bad become too firmly embedded in the new land. But he wanted to see the old folk again and to visit my mother's grave. He became mortally ill a few months before we had planned to go and, when he knew that he was dying, he made me promise to go on my own.
I hired a car the day after landing and bought a comprehensive book of maps, which I found most helpful on the cross-country journey, but which I did not think I should need on the last stage. It was not that I actually remembered anything at all. But my father had described over and over again what we should see at every milestone, after leaving the nearest town, so that I was positive I should recognize it as familiar territory. Well, I had been wrong, for I was now lost.
I looked at the map and then at the millimeter. I had come ten miles since leaving the town, and at this point, according to my father, I should be looking at farms and cottages in a valley, with the spire of the church of our village showing in the far distance. I could see no valley, no farms, no cottages and no church spire -- only a lake. I decided that I must have taken a wrong turning somewhere. So I drove back to the town and began to retrace the route, taking frequent glances at the map. I landed up at the same corner. The curious thing was that the lake was not marked on the map. I left as if I had stumbled into a nightmare country, as you sometimes do in dreams. And, as in a nightmare, there was nobody in sight to help me. Fortunately for me, as I was wondering what to do next, there appeared on the horizon a man on horseback, riding in my direction. I waited till he came near, then I asked him the way to our old village. He said that there was now no village. I thought he must have misunderstood me, so I repeated its name. This time he pointed to the lake. The village no longer existed because it had been submerged, and all the valley too. The lake was not a natural one, but a man-made reservoir.
New words and expressions 生词和短语
alien
emigrate
v. 移居（国外）
absorb
v. 全神贯注于
embedded
mortally
comprehensive
milestone
n. 里程碑
territory
n. 领地；地区
milometer
n. 计程表
spire
n. （教堂的）塔尖
retrace
v. 返回，重走
stumble
v. 趔趄地走
horizon
n. 地平线
reservoir
n. 水库
我停下车，让汽车发动机冷却一下，同时查看一下地图。我本想离目的地已经不远，但周围一切对我仍很陌生。我5岁那年，父亲就带我出了国，那是18年前的事了。当时我母亲在一次事故中惨死，父亲未能很快从悲痛与孤独中恢复过来。他身边的一切都是母亲的影子不断勾起他的伤感。于是他决定移居他国。在这个新的国家里，父亲专心致志地为我们俩开创一种新的生活，慢慢地不伤心了。父亲没有再娶，因此，我在没有母亲的环境里长大成人。但我却什么都不缺，他既当父亲又当母亲。他总想将来回国看看，但却不愿长期住下去，因为他与我一样已经把根深深地扎在异国的土地上。 但是，他想看一看家乡父老乡亲，为我的母亲扫墓。就在他计划回国的前几个月，他突然身患绝症。他知道自己已奄奄一息，于是他要我答应一定单独回故乡一趟。
我下飞机后租了一辆车，并买了一本详尽的地图册。在乡间行车途中，我觉得它非常有用，但快到家了，我倒觉得它没什么用了。这倒并非是我背熟了地图，而是父亲曾详细给我讲了，在过了离故乡最近的那个小镇后，在每一个路标处可见到些什么。因此，我相信这段路对我来说会是很熟悉的。唉，实际我错了，我现在迷路了。
我看了看地图，又查了一下里程表。从小镇出来，我走了10英里。照父亲的说法，我面前应是一个山谷，有农场与村舍，还可远远望见老家村子里的教堂的尖顶。可现在我却看不出山谷，看不见农舍，也看见教学尖顶，看见只是一片湖泊。我想一定是什么地方拐错了弯儿。于是我驾车返回小镇，重新按路线行驶。结果又来到刚才那个拐弯处。奇怪的是那个湖没有在地图上标出。我感到自己就像平时作梦那样迷迷糊糊地闯进了恶梦境地。就像在恶梦里一样，见不到一个人可以帮助我。不过，我是幸运的，正当我走投无路之时，从天边出现一个骑马的人向我骑来。等他走近了，问他去老家的路。他说那村子已经没有了。我想他一定误解了我的意思，于是又说一遍村庄的名字。这次他用手指了一下那个湖。村庄已不复存在，因为已经为水所淹，山谷也被水淹没了。这不是一个天然湖泊，是一座人工修建的水库。
Lesson 58
A spot of bother
一点儿小麻烦
Listen to the tape then answer the question below.
What did the old lady find when she got home?
New words and expressions 生词和短语
life
n. 电梯
monstrous
negligence
n. 粗心大意
lurk
v. 潜藏
hinder
v. 妨碍
fingerprint
n. 指纹
chaos
n. 混乱，无秩序
inconceivable
veritable
magpie
n. 喜欢收藏物品的人
prudent
composure
n. 镇静，沉着
intruder
n. 入侵者（尤指欲行窃者）
toss
v. 扔
v. 丢
v. 丢弃
constable
n. 警察
ransack
v. 洗劫
balcony
n. 阳台
fussy
老妇人回到了她居住的公寓楼，心里很高兴。去商店买东西把她搞得筋疲力尽；在回家的路上，她每走一步，就感到手里的篮子又重了一点。她乘上电梯后，只想着午餐和好好休息一下。但她到自己的楼层走出电梯后，就把这两件事忘了个干净，因为她突然发现她家的大门开着。她心想明天上午一定要好好训斥那个干家务的帮手，她竟如此疏忽大意。但突然记起来了，帮手是在她出去买东西之前走的，她还记得曾用了两把钥匙把大门锁上了。她慢慢地走进前厅，立即发现所有的房门都敞开着，而她记得在出门买东西前，她按老规矩是把房门一一锁上的。她往起居室里看去，写字台边一片狼籍。事情很清楚，在她外出时，窃贼曾闯进家门。她第一个条件反射是各个房间搜寻一下窃贼，但转念一想，像她这个年纪，最好找个人一起去。于是她到地下室去找看门的人。这时她两腿累得开始发抖，于是坐了下来，喝了一杯浓茶。与此同时，看门的人给警察挂了电话。此刻老妇人也镇定了下来，准备在看门人的协助下搜寻可能仍躲藏在她房里的窍贼。
他俩搜遍这每一个房间，小心翼翼地不接触任何东西，因为他们怕妨碍警察寻找指纹。房间里的紊乱状况是无法想像的。老妇人在这套公寓里住了30年，她又是个名副其实的收藏家。看来她的每一件东西都被翻了出来，并且被里里外外看了遍。这样一来，她倒是容易将那些几年前就该扔掉的东西找出来了。过了一会儿，一位巡官带着一名警察来了。她向他们讲述了发现公寓遭劫的经过。巡官开始搜寻指纹，警察经检查发现大门锁头并无撬过的迹象。由此可以证明，窍贼或者是用万能钥匙，或者是翻越阳台进来的。巡官没有发现指纹，却发现了一个装有珠宝的、肮脏的红包袱。老妇人说那不是她的。很明显，闯进这套公寓的窃贼那天并不是首次作案，而且他一定受了惊吓。巡官请老妇人在次日之前设法查清丢了些什么，并劝她几夜之内不要独自一人在公寓过夜。老妇人觉得巡官大惊小怪，但既然看门人也同意他的意见，她只得打电话向女儿求援，说她碰到了一点儿小麻烦。
Lesson 59
Collecting
Listen to the tape then answer the question below.
What in particular does a person gain when he or she becomes a serious collector?
People tend to amass possessions, sometimes without being aware of doing so. Indeed they can have a delightful surprise when they find something useful which they did not know they owned. Those who never have to move house become indiscriminate collectors of what can only be described as clutter. They leave unwanted objects in drawers, cupboards and attics for years, in the belief that they may one day need just those very things. As they grow old, people also accumulate belongings for two other reasons, lack of physical and mental energy, both of which are essential in turning out and throwing away, and sentiment. Things owned for a long time are full associations with the past, perhaps with relatives who are dead, and so they gradually acquire a value beyond their true worth.
Some things are collected deliberately in the home in an attempt to avoid waste. Among these I would list string and brown paper, kept by thrifty people when a parcel has been opened, to save buying these two requisites. Collecting small items can easily become a mania. I know someone who always cuts sketches out from newspapers of model clothes that she would like to buy if she had the money. As she is not rich, the chances that she will ever be able to afford such purchases are remote; but she is never sufficiently strong-minded to be able to stop the practice. It is a harmless bait, but it litters up her desk to such an extent that every time she opens it, loose bits of paper fall out in every direction.
Collecting as a serous hobby is quite different and has many advantages. It provides relaxation for leisure hours, as just looking at one's treasures is always a joy. One does not have to go outside for amusement, since the collection is housed at home. Whatever it consists of, stamps, records, first editions of books china, glass, antique furniture, pictures, model cars, stuffed birds, toy animals, there is always something to do in connection with it, from finding the right place for the latest addition, to verifying facts in reference books. This hobby educates one not only in the chosen subject, but also in general matters which have some bearing on it. There are also other benefits. One wants to meet like-minded collectors, to get advice, to compare notes, to exchange articles, to show off the latest find. So one's circle of friends grows. Soon the hobby leads to travel, perhaps to a meeting in another town, possibly a trip abroad in search of a rare specimen, for collectors are not confined to any one country. Over the years, one may well become a authority on one's hobby and will very probably be asked to give informal talks to little gatherings and then, if successful, to larger audiences. In this way self-confidence grows, first from mastering a subject, then from being able to take about it. Collecting, by occupying spare time so constructively, makes a person contented, with no time for boredom.
New words and expressions 生词和短语
amass
v. 积聚
indiscriminate
clutter
n. 一堆杂物
string
n. 细线
requisite
n. 必需品
mania
n. 癖好
sketch
n. 草图，图样
remote
strong-minded
relaxation
n. 休息，娱乐
verify
v. 查证，核实
bearing
n. 关系，联系
like-minded
specimen
n. 标本
constructively
contented
boredom
n. 烦恼，无聊
人们喜欢收藏东西，有时并没有意识到自己在这样做。确实，一旦无意之中从自己的收藏品中找到某件有用的东西时，可以给人一种惊喜的感觉。那些从来不必搬家的人们成了一种无所无容的收藏家。他们专门收藏那些只能被称作杂货的东西。他们在抽屉里，碗柜中、阁楼上堆放着一些不用的东西，一放就是好几年，相信总有一天需要的正好是那些东西。人们年老之后也喜欢收藏东西，不过是出于两个不同的原因：一是体力，精力均告不佳，这二者是清除无用的东西必不可少的因素；另一原因是感情因素。东西搁得时间久了，便会充满着与过去岁月的联系，比方说与死去的亲戚有关。因此这些东西慢慢获得了一种超出它本身的价值。
居家度日，有目的地收藏某些东西是为了防止浪费。这些东西中我想举出线绳和包装纸为例。节俭的人们打开包裹后便把这两样必备的东西收藏起来。省得日后去买。收集小玩艺儿很容易着迷。我认识一个人，她总喜欢从报纸上剪下流行服装的图样，等以后有钱时去买服装。由于她并不富裕，她买得起这些服装的可能性十分渺茫。但她又缺乏足够坚强的意志把这一收集活动停下来。这种习惯无害，只把写字台里堆得满满当当，以致每次打开抽屉总能带出许多纸片四处飞扬。
作为一种严肃的业余爱好的收藏活动完全是另外一回事，它具有许多益处。它可以使人在闲暇中得到休息，因为欣赏自己收藏的珍品总会充满了乐趣。人们不必走到户外去寻求娱乐，因为收藏品都是存放在家中。不管收藏品是什么，邮票、唱片、头版书籍、瓷器、玻璃杯、老式家具、绘画、模型汽车、鸟类标本，还是玩具动物，从为新增添的收藏品寻找摆放位置到核对参考书中的事实，总归有事可做。这种爱好不仅能使人从选择的专题中受到教育，而且也能从与之有关的一般事物中获得长进。除此之外，还有其他的益处。收藏者要会见情趣相投的收藏者，以获取教益，交流经验、交换收藏品，炫耀自己的最新收藏。朋友的圈子就这样不断扩大。用不了多久，有这种爱好的人便开始旅行，也许是去另一个城市参加会议，也可能是出国寻找一件珍品，因为收藏家是不分国籍的。一人积了多年经验会成为自己这种爱好的权威，很可能应邀在小型集会上作非正式的讲话。如果讲得好，可能向更多人发表演说。这样，你自信心不断增强，先是因为掌握一门学问，接下来是因为能够就此发表见解。收藏活动通过富有建设性地利用业余时间使人感到心满意足，不再有无聊之日。
Lesson 60
Too early and too late
太早和太晚
Listen to the tape then answer the question below.
Why did the young girl miss the train?
Punctuality is a necessary habit in all public affairs in civilized society. Without it, nothing could ever be brought to a conclusion; everything would be in state of chaos. Only in a sparsely-populated rural community is it possible to disregard it. In ordinary living, there can be some tolerance of unpunctuality. The intellectual, who is working on some abstruse problem, has everything coordinated and organized for the matter in hand. He is therefore forgiven if late for a dinner party. But people are often reproached for unpunctuality when their only fault is cutting things fine. It is hard for energetic, quick-minded people to waste time, so they are often tempted to finish a job before setting out to keep an appointment. If no accidents occur on the way, like punctured tires, diversions of traffic, sudden descent of fog, they will be on time. They are often more industrious, useful citizens than those who are never late. The over-punctual can be as much a trial to others as the unpunctual. The guest who arrives half an hour too soon is the greatest nuisance. Some friends of my family had this irritating habit. The only thing to do was ask them to come half an hour later than the other guests. Then they arrived just when we wanted them.
If you are citing a train, it is always better to be comfortably early than even a fraction of a minted too late. Although being early may mean wasting a little time, this will be less than if you miss the train and have to wait an hour or more for the next one; and you avoid the frustration of arriving at the very moment when the train is drawing out of the station and being unable to get on it. An even harder situation is to be on the platform in good time for a train and still to see it go off without you. Such an experience befell a certain young girl the first time she was traveling alone.
She entered the station twenty minutes before the train was due, since her parents had impressed upon her that it would be unforgivable to miss it and cause the friends with whom she was going to stay to make two journeys to meet her. She gave her luggage to a porter and showed him her ticket. To her horror he said that she was two hours too soon. She felt inhere handbag for the piece of paper on which her father had written down al the details of the journey and gave it to the porter. He agreed that a train did come into the station at the time on the paper and that it did stop, but only to take on mail, not passengers. The girl asked to see a timetable, feeling sure that her father could not have made such a mistake. The porter went to fetch one and arrive back with the station master, who produced it with a flourish and pointed out a microscopic 'o' beside the time of the arrival of the train at his station; this little 'o' indicated that the train only stopped for mail. Just as that moment the train came into the station. The girl, tears streaming down her face, begged to be allowed to slip into the guard's van. But the station master was adamant: rules could not be broken and she had to watch that train disappear towards her destination while she was left behind.
New words and expressions 生词和短语
punctuality
n. 准时
rural
disregard
v. 不顾，无视
intellectual
n. 知识分子
abstruse
coordinate
v. 协调
reproach
v. 责备
puncture
v. 刺破（轮胎）
diversion
n. 改道，绕道
trial
n. 讨厌的事，人
fraction
n. 很小一点儿
flourish
n. 挥舞（打手劳）
microscopic
准时是文明社会中进行一切社交活动时必须养成的习惯。不准时将一事无成，事事都会陷入混乱不堪的境地。只有在人口稀少的农村，才可以忽视准时的习惯。在日常生活中人们可以容忍一定程度的不准时。一个专心钻研某个复杂问题的知识分子，为了搞好手头的研究，要把一切都协调一致，组织周密。因此，他要是赴宴迟到了会得到谅解。但有些人不准时常常因为掐钟点所致，他们常常受到责备，精力充沛、头脑敏捷的人极不愿意浪费时间，因此他们常想做完一件事后再去赴约。要是路上没有发生如爆胎、改道、突然起雾等意外事故，他们决不会迟到。他们与那些从不迟到的人相比，常常是更勤奋有用的公民。早到的人同迟到的人一样令人讨厌。客人提前半小时到达是令人讨厌的。我家有几个朋友就有这有令人恼火的习惯。唯一的办法就是请他们比别的客人晚来半小时。这样，他们可以恰好在我们要求的时间到达。
如果赶火车，早到总比晚到好，哪怕早到一会儿也好。虽然早到可能意味着浪费一点时间，但这比误了火车等上一个多小时坐下班车浪费的时间要少，而且可以避免那种正好在火车驶出站时赶到车站，因上不去车而感到的沮丧。更难堪的情况是虽然及时赶到站台上，却眼睁睁地看着那趟火车启动，把你抛下。一个小姑娘第一次单独出门就碰到了这种情况。
在火车进站20分钟前她就进了车站。因为她的父母再三跟她说，如果误了这趟车，她的东道主朋友就得接她两趟，这是不应该的。她把行李交给搬运工并给他看了车票。搬运工说她早到了两个小时，她听后大吃一惊。她从钱包里摸出一张纸条，那上面有她父亲对这次旅行详细说明，她把这张纸条交给了搬运工。搬运工说，正如纸条所说，确有一趟火车在那个时刻到站，但它只停站装邮件，不载旅客。姑娘要求看到时刻表，因为她相信父亲不能把这么大的事弄错。搬运工跑回去取时刻表，同时请来了站长。站长拿着时刻表一挥手，指着那趟列车到站时刻旁边一个很小的圆圈标记。这个标记表示列车是为装邮件而停车。正在这时，火车进站了。女孩泪流满面，央求让她不声不响地到押车员车厢里去算了。但站长态度坚决，规章制度不能破坏，姑娘只得眼看那趟火车消逝在她要去的方向而撇下了她。
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Unit 1
Lesson 1
Finding fossil man 发现化石人
First listen and then answer the following question.
Why are legends handed down by storytellers useful?
We can read of things that happened 5,000 years ago in the Near East, where people first learned to write. But there are some parts of the word where even now people cannot write. The only way that they can preserve their history is to recount it as sagas -- legends handed down from one generation of another. These legends are useful because they can tell us something about migrations of people who lived long ago, but none could write down what they did. Anthropologists wondered where the remote ancestors of the Polynesian peoples now living in the Pacific Islands came from. The sagas of these people explain that some of them came from Indonesia about 2,000 years ago.
But the first people who were like ourselves lived so long ago that even their sagas, if they had any, are forgotten. So archaeologists have neither history nor legends to help them to find out where the first 'modern men' came from.
Fortunately, however, ancient men made tools of stone, especially flint, because this is easier to shape than other kinds. They may also have used wood and skins, but these have rotted away. Stone does not decay, and so the tools of long ago have remained when even the bones of the men who made them have disappeared without trace.
ROBIN PLACE Finding fossil man
New words and expressions 生词和短语
fossil man (title)
recount
v. 叙述
saga
n. 英雄故事
legend
n. 传说，传奇
migration
n. 迁移，移居
anthropologist
n. 人类学家
archaeologist
n. 考古学家
ancestor
n. 祖先
Polynesian
Indonesia
n. 印度尼西亚
flint
n. 燧石
rot
n. 烂掉
我们从书籍中可读到5,000 年前近东发生的事情，那里的人最早学会了写字。但直到现在,世界上有些地方，人们还不会书写。 他们保存历史的唯一办法是将历史当作传说讲述，由讲述人一代接一代地将史实描述为传奇故事口传下来。人类学家过去不清楚如今生活在太平洋诸岛上的波利尼西亚人的祖先来自何方，当地人的传说却告诉人们：其中一部分是约在2,000年前从印度尼西亚迁来的。
但是，和我们相似的原始人生活的年代太久远了，因此，有关他们的传说既使有如今也失传了。于是，考古学家们既缺乏历史记载，又无口头传说来帮助他们弄清最早的“现代人”是从哪里来的。
然而， 幸运的是，远古人用石头制作了工具，特别是用燧石，因为燧石较之其他石头更容易成形。他们也可能用过木头和兽皮，但这类东西早已腐烂殆尽。石头是不会腐烂的。因此，尽管制造这些工具的人的骨头早已荡然无存，但远古时代的石头工具却保存了下来。
Lesson 2
Spare that spider
不要伤害蜘蛛
First listen and then answer the following question.
How much of each year do spiders spend killing insects?
Why, you may wonder, should spiders be our friends? Because they destroy so many insects, and insects include some of the greatest enemies of the human race. Insects would make it impossible for us to live in the world; they would devour all our crops and kill our flocks and herds, if it were not for the protection we get from insect-eating animals. We owe a lot to the birds and beasts who eat insects but all of them put together kill only a fraction of the number destroyed by spiders. Moreover, unlike some of the other insect eaters, spiders never do the harm to us or our belongings.
Spiders are not insects, as many people think, nor even nearly related to them. One can tell the difference almost at a glance, for a spider always has eight legs and insect never more than six.
How many spiders are engaged in this work no our behalf? One authority on spiders made a census of the spiders in grass field in the south of England, and he estimated that there were more than 2,250,000 in one acre; that is something like 6,000,000 spiders of different kinds on a football pitch. Spiders are busy for at least half the year in killing insects. It is impossible to make more than the wildest guess at how many they kill, but they are hungry creatures, not content with only three meals a day. It has been estimated that the weight of all the insects destroyed by spiders in Britain in one year would be greater than the total weight of all the human beings in the country.
T. H. GILLESPLE Spare that spider from The Listener
New words and expressions
beast
n. 野兽
census
n. 统计数字
acre
n. 英亩
content
你可能会觉得奇怪， 蜘蛛怎么会是我们的朋友呢？因为它们能消灭那么多的昆虫，其中包括一些人类的大敌，要不是人类受一些食虫动物的保护，昆虫就会使我们无法在地球上生活下去，昆虫会吞食我们的全部庄稼，杀死我们的成群的牛羊。我们要十分感谢那些吃昆虫的鸟和兽，然而把它们所杀死的昆虫全部加在一起也只相当于蜘蛛所消灭的一小部分。此外，蜘蛛不同于其他食虫动物，它们丝毫不危害我们和我们的财物。
许多人认为蜘蛛是昆虫，但它们不是昆虫，甚至与昆虫毫无关系。人们几乎一眼就能看出二者的差异，因为蜘蛛都是8条腿，而昆虫的腿从不超过6条。
有多少蜘蛛在为我们效力呢？一位研究蜘蛛的权威对英国南部一块草坪上的蜘蛛作了一次调查。他估计每英亩草坪里有225万多只蜘蛛。这就是说，在一个足球场上约有600万只不同种类的蜘蛛。蜘蛛至少有半年在忙于吃昆虫。它们一年中消灭了多少昆虫，我们简直无法猜测，它们是吃不饱的动物，不满意一日三餐。据估计，在英国蜘蛛一年里所消灭昆虫的重量超过这个国家人口的总重量。
Lesson 3
Matterhorn man
马特霍恩山区人
First listen and then answer the following question.
What was the main objective of early mountain climbers?
Modern alpinists try to climb mountains by a route which will give them good sport, and the more difficult it is, the more highly it is regarded. In the pioneering days, however, this was not the case at all. The early climbers were looking for the easiest way to the top, because the summit was the prize they sought, especially if it and never been attained before. It is true that during their explorations they often faced difficulties and dangers of the most perilous nature, equipped in a manner with would make a modern climber shudder at the thought, but they did not go out of their way to court such excitement. They had a single aim, a solitary goal -- the top!
It is hard for us to realize nowadays how difficult it was for the pioneers. Except for one or two places such as Zermatt and Chamonix, which had rapidly become popular, Alpine village tended to be impoverished settlements cut off from civilization by the high mountains. Such inns as there were generally dirty and flea-ridden; the food simply local cheese accompanied by bread often twelve months old, all washed down with coarse wine. Often a valley boasted no inn at all, and climbers found shelter wherever they could -- sometimes with the local priest (who was usually as poor as his parishioners), sometimes with shepherds or cheese-makers. Invariably the background was the same: dirt and poverty, and very uncomfortable. For men accustomed to eating seven-course dinners and sleeping between fine linen sheets at home, the change to the Alps must have very hard indeed.
WALTER UNSWORTH Matterhorn Man
New words and expressions 生词和短语
Matterhorn
n. 马特霍恩峰（阿尔卑斯山之一，在意大利和瑞士边境）
alpinist
n. 登山运动员
pioneer
v. 开辟，倡导；
n. 先锋，开辟者
summit
n. 顶峰
attain
v. 到达
perilous
shudder
v. 不寒而栗
court
v. 追求
solitary
impoverish
v. 使贫困
Alpine
flea-ridden
coarse
boast
v. 自恃有
parishioner
n. 教区居民
shepherd
n. 牧羊人
linen
n. 亚麻布床单
the Alps
n. 阿尔卑斯山脉
现代登山运动员总想找一条能够给他们带来运动乐趣的路线来攀登山峰。他们认为， 道路愈艰险愈带劲儿。然而，在登山运动的初期，全然不是这种情况。早期登山者所寻找的是通往山顶的最方便的途径，因为顶峰特别是前人未曾到过的顶峰 -- 才是他们寻求的目标。确实，在探险中他们经常遇到惊心动魄的困难和危险，而他们装备之简陋足以使现代登山者一想起来就胆战心惊。但是，他们并非故意寻求这种刺激，他们只有一个目标，唯一的目标 -- 顶峰！
我们今天很难想像昔日的登山先驱们是多么艰苦。除了泽曼特和夏蒙尼等一两个很快出了名的地方外，阿尔卑斯山山区的小村几乎全是高山环抱、与世隔绝的穷乡僻壤。那里的小客栈一般都很肮脏，而且跳蚤猖獗。 食物是当地的干酪和通常存放了一年之久的面包，人们就着劣酒吞下这种食物。山谷里常常没有小客栈，登山者只好随遇而安。有时同当地牧师 （他通常和他的教民一样穷）住在一起，有时同牧羊人或制乳酪的人住在一起。无论住在哪儿，情况都一样：肮脏、贫穷，极其不舒适。对于过惯了一顿饭吃7道菜、睡亚麻细布床单的人来说，变换一下生活环境来到阿尔卑斯山山区，那一定是很艰难的。
Lesson 4
Seeing hands
能看见东西的手
First listen and answer the following question.
How did Vera discover she had this gift of second sight?
Several cases have been reported in Russia recently of people who can detect colours with their fingers, and even see through solid and walls. One case concerns and eleven-year-old schoolgirl, Vera Petrova, who has normal vision but who can also perceive things with different parts of her skin, and through solid walls. This ability was first noticed by her father. One day she came into his office and happened to put her hands on the door of a locked safe. Suddenly she asked her father why he kept so many old newspapers locked away there, and even described the way they were done up in bundles.
Vera's curious talent was brought to the notice of a scientific research institute in the town of Ulyanovsk, near where she lives, and in April she was given a series of tests by a special commission of the Ministry of Health of the Russian Federal Republic. During these tests she was able to read a newspaper through an opaque screen and, stranger still, by moving her elbow over a child's game of Lotto she was able to describe the figures and colours printed on it; and, in another instance, wearing stockings and slippers, to make out with her foot the outlines and colours of a picture hidden under a carpet. Other experiments showed that her knees and shoulders had a similar sensitivity. During all these tests Vera was blindfold; and, indeed, except when blindfold she lacked the ability to perceive things with her skin. It was also found that although she could perceive things with her fingers this ability ceased the moment her hands were wet.
ERIC DE MAUNY Seeing hands from The Listener
New words and expressions
solid
safe
n. 保险柜
Ulyanovsk
n. 乌里扬诺夫斯克
commission
n. 委员会
opaque
lotto
n. 一种有编号的纸牌
slipper
n. 拖鞋
blindfold
俄罗斯最近报导了几个事例，有人能用手指看书识字和辨认颜色，甚至能透过厚实的门和墙看到东西。 其中有一例谈到有一个名叫维拉.彼托洛娃的11岁学生。她的视力与常人一样，但她还能用皮肤的不同部位辨认东西，甚至看穿坚实的墙壁。是她父亲首先发现她这一功能的。一天，维拉走进父亲的办公室，偶然把手放在一个锁着的保险柜的门上，她突然问父亲为什么把这么多的旧报纸锁在柜子里，还说了报纸捆扎的情况。
维拉的特异功能引起了她家附近乌里扬诺夫斯克城一个科研单位的注意。4月里，俄罗斯卫生部一个特别委员会对她进行了一系列的测试。在这些测试中，她能隔着不透明的屏幕读报纸。更为奇怪的是，她把肘部在儿童玩的“罗托”纸牌上移动一下，便能说出印在纸牌上的数字和颜色。还有一次，她穿着长筒袜子和拖鞋，能用脚步识别出藏在地毯下面的一幅画的轮廓和颜色。其他实验表明，她的膝盖和双肩有类似的感觉能力，在所有这些实验中，维拉的双眼都是蒙着的。如果不蒙上双眼她的皮肤就不再具有识别物体的能力。这是千真万确的。同时还发现，尽管她能用手指识别东西，但她的手一旦弄湿，这种功能便会立即消失。
Lesson 5
Youth
青年
First listen and then answer the following question:
How does the writer like to treat young people?
People are always talking about 'the problem of youth'. If there is one -- which I take leave to doubt -- then it is older people who create it, not the young themselves. Let us get down to fundamentals and agree that the young are after all human beings -- people just like their elders. There is only one difference between an old man and a young one: the young man has a glorious future before him and the old one has a splendid future behind him: and maybe that is where the rub is.
When I was a teenager, I felt that I was just young and uncertain -- that I was a new boy in a huge school, and I would have been very pleased to be regarded as something so interesting as a problem. For one thing, being a problem gives you a certain identity, and that is one of the things the young are busily engaged in seeking.
I find young people exciting. They have an air of freedom, and they not a dreary commitment to mean ambitions or love of comfort. They are not anxious social climbers, and they have no devotion to material things. All this seems to me to link them with life, and the origins of things. It's as if they were, in some sense, cosmic beings in violent and lovely contrast with us suburban creatures. All that is in my mind when I meet a young person. He may be conceited, ill-mannered, presumptuous or fatuous, but I do not turn for protection to dreary cliches about respect of elders -- as if mere age were a reason for respect. I accept that we are equals, and I will argue with him, as an equal, if I think he is wrong.
FIELDEN HUGHES from Out of the Air, The Listener
New words and expression 生词和短语
leave
n. 允许
fundamentals
n. 基本原则
glorious
splendid
rub
n. 难题
identity
n. 身份
dreary
commitment
n. 信奉
mean
social climber
追求更高社会地位的，向上爬的人
devotion
n. 热爱
cosmic
suburban
conceited
presumptuous
fatuous
cliche
n. 陈词滥调
人们总是在谈论“青年问题”。如果这个问题存在的话 -- 请允许我对此持怀疑态度 -- 那么，这个问题是由老年人而不是青年人造成的。让我们来认真研究一些基本事实：承认青年人和他们的长辈一样也是人。老年人和青年人只有一个区别：青年人有光辉灿烂的前景，而老年人的辉煌已成为过去。 问题的症结恐怕就在这里。
我十几岁时，总感到自己年轻，有些事拿不准 -- 我是一所大学里的一名新生，如果我当时真的被看成像一个问题那样有趣，我会感到很得意的。因为这至少使我得到了某种承认，这正是年轻人所热衷追求的。
我觉得年轻人令人振奋，无拘无束。他们既不追逐卑鄙的名利，也不贪图生活的舒适。他们不热衷于向上爬，也不一味追求物质享受。在我看来，所有这些使他们与生命和万物之源联系在了一起。从某种意义上讲，他们似乎是宇宙人，同我们这些凡夫俗子形成了强烈而鲜明的对照。每逢我遇到年轻人，脑子里就想到这些年轻人也许狂妄自负，举止无理，傲慢放肆，愚昧无知，但我不会用应当尊重长者这一套陈词滥调来为我自己辨护，似乎年长就是受人尊敬的理由。我认为我和他们是平等的。如果我认为他们错了，我就以平等的身份和他们争个明白。
Lesson 6
The sporting spirit
体育的精神
First listen and then answer the following question.
How does the writer describe sport at the international level?
I am always amazed when I hear people saying that sport creates goodwill between the nations, and that if only the common peoples of the would could meet one another at football or cricket, they would have no inclination to meet on the hattlefield. Even if one didn't know from concrete examples (the 1936 Olympic Games, for instance) that international sporting contests lead to orgies of hatred, one could deduce if from general principles.
Nearly all the sports practised nowadays are competitive. You play to win, and the game has little meaning unless you do your utmost to win. On the village green, where you pick up sides and no feeling of local patriotism is involved, it is possible to play simply for the fun and exercise: but as soon as a the question of prestige arises, as soon as you feel that you and some larger unit will be disgraced if you lose, the most savage combative instincts are aroused. Anyone who has played even in a school football match knows this. At the international level, sport is frankly mimic warfare. But the significant thing is not the behaviour of the players but the attitude of the spectators: and, behind the spectators, of the nations who work themselves into furies over these absurd contests, and seriously believe -- at any rate for short periods -- that running, jumping and kicking a ball are tests of national virtue.
GEORGE ORWELL The sporting spirit
New words and expression
goodwill
n. 友好
cricket
n. 板球
inclination
n. 意愿
contest
n. 比赛
orgy
n. 无节制的，放荡
deduce
v. 推断
competitive
patriotism
n. 地方观念，爱国主义
disgrace
v. 使丢脸
savage
combative
mimic warfare
模拟战争
behaviour
n. 行动，举止
absurd
当我听人们说体育运动可创造国家之间的友谊，还说各国民众若在足球场或板球场上交锋，就不愿在战场上残杀的时候，我总是惊愕不已。一个人即使不能从具体的事例（例如1936年的奥林匹克运动会）了解到国际运动比赛会导致疯狂的仇恨，也可以从常理中推断出结论。
现在开展的体育运动几乎都是竞争性的。参加比赛就是为了取胜。如果不拚命去赢，比赛就没有什么意义了。 在乡间的草坪上，当你随意组成两个队，并且不涉及任何地方情绪时，那才可能是单纯的为了娱乐和锻炼而进行比赛。可是一量涉及到荣誉问题，一旦你想到你和某一团体会因为你输而丢脸时，那么最野蛮的争斗天性便会激发起来。即使是仅仅参加过学校足球赛的人也有种体会。在国际比赛中，体育简直是一场模拟战争。但是，要紧的还不是运动员的行为，而是观众的态度，以及观众身后各个国家的态度。面对着这些荒唐的比赛，参赛的各个国家会如痴如狂，甚至煞有介事地相信 -- 至少在短期内如此 -- 跑跑、跳跳、踢踢球是对一个民族品德素质的检验。
Lesson 7
Bats
蝙蝠
First listen and then answer the following question.
In what way does echo-location in bats play an utilitarian role?
Not all sounds made by animals serve as language, and we have only to turn to that extraordinary discovery of echo-location in bats to see a case in which the voice plays a strictly utilitarian role.
To get a full appreciation of what this means we must turn first to some recent human inventions. Everyone knows that if he shouts in the vicinity of a wall or a mountainside, an echo will come back. The further off this solid obstruction, the longer time will elapse for the return of the echo. A sound made by tapping on the hull of a ship will be reflected from the sea bottom, and by measuring the time interval between the taps and the receipt of the echoes, the depth of the sea at that point can be calculated. So was born the echo-sounding apparatus, now in general use in ships. Every solid object will reflect a sound, varying according to the size and nature of the object. A shoal of fish will do this. So it is a comparatively simple step from locating the sea bottom to locating a shoal of fish. With experience, and with improved apparatus, it is now possible not only to locate a shoal but to tell if it is herring, cod, or other well-known fish, by the pattern of its echo.
It has been found that certain bats emit squeaks and by receiving the echoes, they can locate and steer clear of obstacles -- or locate flying insects on which they feed. This echo-location in bats is often compared with radar, the principle of which is similar.
MAURICE BURTON Curiosities of animal life
New words and expressions生词和短语
bat
n. 蝙蝠
strictly
utilitarian
appreciation
n. 理解
elapse
v. 障碍物
hull
n. 消逝
interval
n. 船体
receipt
n. 间隔
apparatus
n. 收到
shoal
n. 仪器
herring
n. 鱼群
cod
n. 鳕鱼
squeak
n. 尖叫声
动物发出的声音不都是用作语言交际。我们只要看一看蝙蝠回声定位这一极不寻常的发现，就可以探究一下声音在什么情况下有绝对的实用价值。
要透彻理解这句话的意义，我们应先回顾一下人类最近的几项发明。大家都知道，在墙壁或山腰附近发出的喊声，就会听到回声。固体障碍物越远。回声返回所用时间就越长。敲打船体所发了的声音会从海底传回来，测出回声间隔的时间，便可算出该处海洋的深度。这样就产生了目前各种船舶上普遍应用的回声探测仪。任何固体者反射声音，反射的声音因物体的大小和性质的不同而不同。鱼群也反射声音。从测定海深到测定鱼群，这一进展比较容易。根据经验和改进了的仪器，不仅能够确定鱼群的位置，而且可以根据鱼群回声的特点分辨出是鲱鱼、鳕鱼，这是人们所熟悉的其他鱼。
人们发现，某些蝙蝠能发出尖叫声，并能通过回声来确定并躲开障碍物，或找到它们赖以为生的昆虫。蝙蝠这种回声定位常常可与雷达相比较，其原理是相似的。
Lesson 8
贸易标准
First listen and then answer the following question.
What makes trading between rich countries difficult?
Chickens slaughtered in the United States, claim officials in Brussels, are not fit to grace European tables. No, say the American: our fowl are fine, we simply clean them in a different way. These days, it is differences in national regulations, far more than tariffs, that put sand in the wheels of trade between rich countries. It is not just farmers who are complaining. An electric razor that meets the European Union's safety standards must be approved by American testers before it can be sold in the United States, and an American-made dialysis machine needs the EU's okay before is hits the market in Europe.
As it happens, a razor that is safe in Europe is unlikely to electrocute Americans. So, ask businesses on both sides of the Atlantic, why have two lots of tests where one would do? Politicians agree, in principle, so America and the EU have been trying to reach a deal which would eliminate the need to double-test many products. They hope to finish in time for a trade summit between America and the EU on May 28TH. Although negotiators are optimistic, the details are complex enough that they may be hard-pressed to get a deal at all.
Why? One difficulty is to construct the agreements. The Americans would happily reach one accord on standards for medical devices and them hammer out different pacts covering, say, electronic goods and drug manufacturing. The EU -- following fine continental traditions -- wants agreement on general principles, which could be applied to many types of products and perhaps extended to other countries.
From: The Economist, May 24th, 1997
New words and expressions 生词和短语
slaughter
v. 屠宰
fit
grace
v. 给...增光
tariff
n. 关税
standard
n. 标准
dialysis
n. 分离，分解；透析，渗析
electrocute
v. 使触电身亡
eliminate
v. 消灭
accord
n. 协议
device
n. 仪器，器械
hammer out
v. 推敲
pact
n. 合同，条约，公约
布鲁塞尔的官员说，在美国屠宰的鸡不适于用来装点欧洲的餐桌。不，美国人说，我们的家禽很好，只是我们使用了另一种清洗方式。当前，是各国管理条例上的差异，而不是关税阻碍了发达国家之间的贸易。并不仅仅是农民在抱怨。一把符合欧洲联盟安全标准的电动剃须刀必须得到美国检测人员的认可，方可在美国市场上销售；而美国制造的透析仪也要得到欧盟的首肯才能进入欧洲市场。
碰巧在欧洲使用安全的剃须刀不大可能使美国人触电身亡，因此，大西洋两岸的企业都在问，当一套测试可以解决问题时，为什么需要两套呢？政治家在原则上同意了， 因此，美国和欧洲一直在寻求达成协议，以便为许多产品取消双重检查。他们希望尽早达成协议，为5月28日举行的美国和欧洲贸易的最高通级会议作准备。然谈判代表持乐观态度，但协议细节如此复杂，他们所面临的困难很可能使他们无法取得一致。
为什么呢？困难之一是起草这些协议。美国人很愿意就医疗器械的标准达成一个协议，然后推敲出不同的合同，用以涵盖 -- 比如说 -- 电子产品和药品的生产。欧洲人遵循优良的大陆传统，则希望就普遍的原则取得一致，而这些原则适用于许多不同产品，同时可能延伸到其它国家。
Lesson 9
Royal espionage
王室谍报活动
First listen and then answer the following question.
What important thing did King Alfred learn when he penetrated the Danish camp of Guthrum?
Alfred the Great acted his own spy, visiting Danish camps disguised as a minstrel. In those days wandering minstrels were welcome everywhere. They were not fighting men, and their harp was their passport. Alfred had learned many of their ballads in his youth, and could vary his programme with acrobatic tricks and simple conjuring.
While Alfred's little army slowly began to gather at Athelney, the king himself set out to penetrate the camp of Guthrum, the commander of the Danish invaders. There had settled down for the winter at Chippenham: thither Alfred went. He noticed at once that discipline was slack: the Danes had the self-confidence of conquerors, and their security precautions were casual. They lived well, on the proceeds of raids on neighbouring regions. There they collected women as well as food and drink, and a life of ease had made them soft.
Alfred stayed in the camp a week before he returned to Athelney. The force there assembled was trivial compared with the Danish horde. But Alfred had deduced that the Danes were no longer fit for prolonged battle: and that their commissariat had no organization, but depended on irregular raids.
So, faced with the Danish advance, Alfred did not risk open battle but harried the enemy. He was constantly on the move, drawing the Danes after him. His patrols halted the raiding parties: hunger assailed the Danish army. Now Alfred began a long series of skirmishes -- and within a month the Danes had surrendered. The episode could reasonably serve as a unique epic of royal espionage!
BERNARD NEWMAN Spies in Britain
New words and expressions 生词和短语
espionage
n. 间谍活动
Alfred
公元871-899 年间任英国国王
Danish
minstrel
n. 中世纪的吟游歌手
wandering
harp
n. 坚琴
n. 民歌
acrobatic
conjuring
n. 魔术
Athelney
n. 阿塞尔纳（英国一个小岛）
Chippenham
n. 切本哈姆（英国一个城市）
thither
Dane
n. 丹麦人
slack
conqueror
n. 征服者
casual
precaution
n. 预防，警惕
proceeds
n. 所得
assemble
v. 集合
trivial
prolonged
commissariat
n. 军粮供应
episode
n. 一个事件，片断
epic
n. 史诗
harry
v. 骚扰
assail
v. 袭击
skirmish
n. 小规模战斗
阿尔弗雷德大帝曾亲自充当间谍。他扮作吟游歌手到丹麦军队的营地里侦察。当时，浪迹天涯的吟游歌手到处受欢迎，他们不是作战人员，竖琴就是他们的通行证。阿尔弗德年轻时学过许多民歌，并能穿插演一些杂技和小魔术使自己的节目多样化。
阿尔弗雷德人数不多的军队开始在阿塞尔纳慢慢集结时，他亲自潜入丹麦入侵司令官古瑟罗姆的营地。丹麦军已在切本哈姆扎下营准备过冬，阿尔弗雷便来到此地。他马上发现丹麦军纪律松弛，他们以征服者自居，安全措施马马虎虎。他们靠掠夺附近的地区的财物过着舒适的生活。他们不仅搜刮吃的喝的，而且抢掠妇女，安逸的生活已使丹麦军队变得软弱无力。
阿尔弗雷德在敌营呆了一个星期后，回到了阿塞尔纳。他集结在那里的军队和丹麦大军相比是微不足道的，然而，阿尔弗雷德断定，丹麦人已不再适应持久的战争，他们的军需供应处于无组织状态，只是靠临时抢夺来维持。
因此，面对丹麦人的进攻，阿尔弗雷德没有贸然同敌人作战，而是采用骚扰敌人的战术。他的部队不停地移动，牵着敌人的鼻子，让他们跟着跑。他派出巡逻队阻止敌人抢劫，因而饥饿威胁着丹麦军队。这时，阿尔弗雷德发起一连串小规模的进攻，结果不出一个月，丹麦人就投降了。这一幕历史可以说是王室谍报活动中最精彩的篇章。.
Unit 2
Lesson 10
Silicon valley
硅谷
First listen and then answer the following question.
What does the computer industry thrive on apart from anarchy?
Technology trends may push Silicon Valley back to the future. Carver Mead, a pioneer in integrated circuits and a professor of computer science at the California Institute of Technology, notes there are now work-stations that enable engineers to design, test and produce chips right on their desks, much the way an editor creates a newsletter on a Macintosh. As the time and cost of making a chip drop to a few days and a few hundred dollars, engineers may soon be free to let their imaginations soar without being penalized by expensive failures. Mead predicts that inventors will be able to perfect powerful customized chips over a weekend at the office -- spawning a new generation of garage start-ups and giving the U.S. a jump on its foreign rivals in getting new products to market fast. 'We're got more garages with smart people,' Mead observes. 'We really thrive on anarchy.'
And on Asians. Already, orientals and Asian Americans constitute the majority of the engineering staffs at many Valley firms. And Chinese, Korean, Filipino and Indian engineers are graduating in droves from California's colleges. As the heads of next-generation start-ups, these Asian innovators can draw on customs and languages to forge righter links with crucial Pacific Rim markets. For instance, Alex Au, a Stanford Ph. D. from Hong Kong, has set up a Taiwan factory to challenge Japan's near lock on the memory-chip market. India-born N.Damodar Reddy's tiny California company reopened an AT & T chip plant in Kansas City last spring with financing from the state of Missouri. Before it becomes a retirement village, Silicon Valley may prove a classroom for building a global business.
US NEWS AND WORLD REPORT, October 2, 1989
New words and expressions 生词和短语
silicon
n. 硅
integrated
circuit
n. 线路，电路
California
n. 加利福尼亚（美国州名）
workstation
n. 工作站
chip
n. 芯片，集成电路片，集成块
n. 时事通讯
Macintosh
n. 苹果机，一种个人电脑
penalize
v. 处罚，惩罚
customize
v. 按顾客具体需要制造
spawn
v. 引起，酿成
thrive
v. 兴旺，繁荣
anarchy
n. 无政府状态，混乱
oriental
n. 东方人
constitute
v. 构成
drove
n. 群
innovator
n. 发明者
forge
v. 发展
memory-chip
n. 内存条
AT & T
美国电话电报公司 (American Telephone and Telegraph)
Kansas
n. 堪萨斯（美国州名）
Missouri
n. 密苏里（美国州名）
技术的发展趋势有可能把硅谷重新推向未来。卡弗.米德 -- 集成电路的一位先驱，加州理工学院的计算机教授 -- 注意到，现在有些计算机工作站使工程技术人员可以在他们的办公桌上设计、试验和生产芯片，就像一位编辑在苹果机上编出一份时事通讯一样。由于制造一块芯片的时间已缩短至几天，费用也只有几百美元，因此，工程技术人员可能很块就可充分发挥他们的想像力，而不会因失败而造成经济上的损失。米德预言发明者可以在办公室用一个周末的时间生产了完美的、功能很强的、按客户需求设计的芯片 -- 造就新一代从汽车间起家的技术人员，在把产品推向市场方面使美国把它的外国对手们打个措手不及。 “我们有更多的汽车间，那里有许多聪明人，”米德说。“我们确实是靠这种无政府状态发展起来的。” 靠的是亚洲人。硅谷许多公司中工程技术人员的大多数是东方人和亚裔美国人。中国、韩国、菲律宾和印度的工程师一批批地从加州的大学毕业。作为新掘起一代的带头人，亚裔发明家可以凭借他们在习惯和语言上的优势，与关键的太平洋沿岸市场建立起更加牢固的联系。比如说，亚历克斯.奥，一位来自香港的斯坦福大学博士，已经在台湾建厂，对日本在内存条市场上近似垄断的局面提出了挑战。印度出生的N.达莫达.雷迪经营的小小的加州公司在堪萨斯城重新启用了美国电话电报公司的一家芯片工厂，并从密苏里州获取了财政上的支持。在硅谷变成一个退休村之前，它很可能成为建立全球商业的一个教学场地。
Lesson 11
How to grow old
如何安度晚年
First listen and then answer the following question.
What, according to the author, is the best way to overcome the fear of death as you get older?
Some old people are oppressed by the fear of death. In the young there is a justification for this feeling. Young men who have reason to fear that they will be killed in battle may justifiably feel bitter in the thought that they have cheated of the best things that life has to offer. But in an old man who has known human joys and sorrows, and has achieved whatever work it was in him to do, the fear of death is somewhat abject and ignoble. The best way to overcome it -- so at least it seems to me -- is to make your interests gradually wider and more impersonal, until bit by bit the walls of the ego recede, and your life becomes increasingly merged in the universal life. An individual human existence should be like a river -- small at first, narrowly contained within its banks, and rushing passionately past boulders and over waterfalls. Gradually the river grows wider, the banks recede, the waters flow more quietly, and in the end, without any visible break, they become merged in the sea, and painlessly lose their individual being. The man who, in old age, can see his life in this way, will not suffer from the fear of death, since the things he cares for will continue. And if, with the decay of vitality, weariness increases, the thought of rest will be not unwelcome. I should wish to die while still at work, knowing that others will carry on what I can no longer do, and content in the thought that what was possible has been done.
BERTRAND RUSSELL How to grow old from Portraits from Memory
New words and expressions 生词和短语
oppress
v. 忧郁，压抑
justification
n. 正当理由
justifiably
cheat
v. 欺骗
abject
ignoble
impersonal
ego
n. 自我
receded
v. 退去
increasing
passionately
painlessly
vitality
n. 精力
weariness
n. 疲惫感
有些老年人因为怕死而感到烦恼。青年人有这种感觉是情有可原的。有理由害怕自己会死在战场上的年轻人，想到自己被剥夺了生活所能给予的最美好的东西时，感到痛苦，这是可以理解的。可是老年人已经饱尝了人间的甘苦，一切能做的都做了，如果怕死，就有点儿可怜又可鄙。克服怕死的最好办法 -- 至少在我看来是这样 -- 就是逐渐使自己的兴趣更加广泛，逐渐摆脱个人狭小的圈子，直到自我的围墙一点一点地倒塌下来，自己的生活慢慢地和整个宇宙的生活融合在一起。个人的存在应该像一条河流，开始很小，被紧紧地夹在两岸中间，接着热情奔放地冲过巨石，飞下瀑布。然后河面渐渐地变宽，两岸后撤，河水流得平缓起来，最后连绵不断地汇入大海，毫无痛苦地失去了自我的存在。上了年纪的人这样看待生命，就不会有惧怕死亡的心情了，因为自己关心的一切事件都会继续下去。 再者，随着精力的衰退，老年人的疲惫会增长，有长眠的愿望未尝不是一件好事情，我希望工作到死为止，明白了有人会继续我的未竟事业，想到能做的事都做了，也就坦然了。
Unit 2
Lesson 12
Banks and their customers
银行和顾客
First listen and then answer the following question.
Why is there no risk to the customer when a bank prints the customer's name on his cheques?
When anyone opens a current account at a bank, he is lending the bank money, repayment of which he may demand at any time, either in cash or by drawing a cheque in favour of another person. Primarily, the banker-customer relationship is that of debtor and creditor -- who is which depending on whether the customer's account is in credit or is overdrawn. But, in addition to that basically simple concept, the bank and its customer owe a large number of obligations to one another. Many of these obligations can give in to problems and complications but a bank customer, unlike, say, a buyer of goods, cannot complain that the law is loaded against him.
The bank must obey its customer's instructions, and not those of anyone else. When, for example, a customer first opens an account, he instructs the bank to debit his account only in respect of cheques draw by himself. He gives the bank specimens of his signature, and there is a very firm rule that the bank has no right or authority to pay out a customer's money on a cheques on which its customer's signature has been forged. It makes no difference that the forgery may have been a very skilful one: the bank must recognize its customer's signature. For this reason there is no risk to the customer in the practice, adopted by banks, of printing the customer's name on his cheques. If this facilitates forgery, it is the bank which will lose, not the customer.
GORDON BARRIE and AUBREY L. DLAMOND The Consumer Society and the Law
New words and expressions 生词和短语
current
account
n. 账户
cash
n. 现金
debtor
n. 支票
debtor
n. 借方
creditor
n. 贷方
obligation
n. 义务
complication
n. 纠纷
debit
v. 把...记入借方
specimen
n. 样本
forge
v. 伪造
forgery
n. 伪造（文件，签名等）
v. 采用
facilitate
v. 使便利
任何人在银行开一个活期账户，就等于把钱借给了银行。这笔钱他可以随时提取，提取的方式可以是取现金，也可以是开一张以他人为收款人的支票。银行与储户的关系主要是债务人和债权人的关系。究竟谁是债务人谁是债权人，要看储户是有结余还是透支。除了这一基本的简单的概念外，银行和储户彼此还需承担大量义务。其中许多义务往往引起问题和纠纷。但是储户不能像货物的买主那样来抱怨法律对自己不利。
银行必须遵照储户的嘱托办事，不能听从其他人的指令。比如，储户首次在银行开户时，嘱咐银行他的存款只能凭本世人签字的支票来提取。他把自己签名的样本交给银行，对此有一条非常严格的规定：银行没有任何权利或理由把储户的钱让伪造储户的支票取走。即使伪造得很巧妙，也不能付款，因为银行有责任辨认出其储户的签名。因此，某些银行已采用把储户印在支票上的作法。这种做法对储户毫无风险。如果因这种作法出现了伪造的话，受损失的将不是储户，而是银行。
Lesson 13
The search for oil
探寻石油
First listen and then answer the following question.
What do oilmen want to achieve as soon as they strike oil?
The deepest holes of all made for oil, and they go down to as much as 25,0000 feet. But we not need to send men down to get the oil our, as we must with other mineral deposits. The holes are only borings, less than a foot in diameter. My particular experience is largely in oil, and the search for oil has done more to improve deep drilling than any other mining activity. When is has been decided where we are going to drill, we put up at the surface an oil derrick. It has to be tall because it is like a giant block and tackle, and we have to lower into the ground and haul out of the ground great lengths of drill pipe which are rotated by an engine at the top and are fitted with a cutting bit at the bottom.
The geologist needs to know what rocks the drill has reached, so every so often a sample is obtained with a coring bit. It cuts a clean cylinder of rock, from which can be seen the strata the drill has been cutting through. Once we get down to the oil, it usually flows to the surface because great pressure, either from or water, is pushing it. This pressure must be under control, and we control it by means of the mud which we circulate down the drill pipe. We endeavour to avoid the old, romantic idea of a gusher, which wastes oil and gas. We want it to stay down the hole until we can lead it off in a controlled manner.
T.F.GASKELL The Search for the Earth's Minerals from Discovery
New words and expressions 生词和短语
mineral
boring
n. 钻孔
derrick
n. 井架
block and tackle
滑轮组
haul
v. 拖，拉
rotate
v. 使转动
cutting bit
钻头
geologist
n. 地质学家
coring
取芯钻头
cylinder
n. 圆柱体
strata
n. 岩层[复]([单]stratum或strata [误用])
circulate
v. 注入，环流
gusher
n. 喷油井
在所有洞穴中，为寻找石油所钻出的洞是最深的，这些洞可深达25,000英尺。但是，我们不必像开采其他矿藏那样，把人送到地下去把石油取出。这些洞只不过是一些钻孔，直径不到1英尺。我是专门搞石油的，寻找石油比其他任何采矿业对改进钻探作的贡献都要大。当确定钻孔地点后，我们就在那里竖起一个井架。井架必须很高，因为它像一个巨型滑轮组。我们必须把很长的钻杆一节节地钻入地下，然后再从地下拉出来。钻杆顶部安装的发动机带动钻杆旋转，它的底部装有钻头。
地质学家需要知道钻头已以到达什么样的岩层，因此时常要用芯钻头取样。这种钻头能切割一段光滑的圆柱形岩石，从中能看出所钻透的地层。一旦到达油层，石油就会由于地下巨大的压力流到地面上来，这种巨大的压力来自地下天然气或水。这种压力必须加以控制，我们让泥桨顺着钻杆向下循环，用这种方法来控制压力。我们尽量避免使用陈旧天真的喷井方法，那样会浪费石油和天然气。我们要让石油留在井下，直到我们能用一种有控制的方法把它引上来为止。
Lesson 14
The Butterfly Effect
蝴蝶效应
First listen and then answer the following question.
Why do small errors make it impossible to predict the weather system with a high degree of accuracy?
Beyond two or three days, the world's best weather forecasts are speculative, and beyond six or seven they are worthless.
The Butterfly Effect is the reason. For small pieces of weather -- and to a global forecaster, small can mean thunderstorms and blizzards -- any prediction deteriorates rapidly. Errors and uncertainties multiply, cascading upward through a chain of turbulent features, from dust devils and squalls up to continent-size eddies that only satellites can see.
The modern weather models work with a grid of points of the order of sixty miles apart, and even so, some starting data has to guessed, since ground stations and satellites cannot see everywhere. But suppose the earth could be covered with sensors spaced one foot apart, rising at one-foot intervals all the way to the top of the atmosphere. Suppose every sensor gives perfectly accurate readings of temperature, pressure, humidity, and any other quantity a meteorologist would want. Precisely at noon an infinitely powerful computer takes all the data and calculates what will happen at each point at 12.01, then 1202, then 12.03...
The computer will still be unable to predict whether Princeton, New Jersey, will have sun or rain on a day one month away. At noon the spaces between the sensors will hide fluctuations that the computer will not know about, tiny deviations from the average. By 12.01, those fluctuations will already have created small errors one foot away. Soon the errors will have multiplied to the ten-foot scale, and so on up to the size of the globe.
JAMES GLEICK, Chaos
New words and expressions 生词和短语
forecast
n. 预报
speculative
blizzard
n. 暴风雪
deteriorate
v. 变坏
multiply
v. 增加
v. 瀑布似地落下
turbulent
dust devil
小尘暴，尘旋风
squall
n. 暴风
eddy
n. 旋涡
grid
n. 坐标方格
sensor
n. 传感器
humidity
n. 温度
meteorologist
n. 气象学家
Princeton
n. 普林斯顿（美国城市名）
New Jersey
n. 新泽西（美国州名）
fluctuation
n. 起伏，波动
deviation
n. 偏差
世界上最好的两三天以上的天气预报具有很强的猜测性，如果超过六七天，天气预报就没有了任何价值。
原因是蝴蝶效应。对于小片的恶劣天气 -- 对一个全球性的气象预报员来说，“小”可以意味着雷暴雨和暴风雪 -- 任何预测的质量会很快下降。错误和不可靠性上升，接踵而来的是一系列湍流的徵状，从小尘暴和暴风发展到只有卫星上可以看到的席卷整块大陆的旋涡。
现代气象模型以一个坐标图来显示，图中每个点大约是间隔60英里。既使是这样，有些开始时的资料也不得不依靠推测，因为地面工作站和卫星不可能看到地球上的每一个地方。假设地球上可以布满传感器，每个相隔1英尺，并按1英尺的间隔从地面一直排列到大气层的顶端。再假定每个传感器都极极端准确地读出了温度、气压、温度和气象学家需要的任何其他数据。在正午时分，一个功能巨大的计算机搜集了所有的资料，并算出在每一个点上12：01、12：02、12：03时可能出现的情况。
计算机无法推断出1个月以后的某一天，新泽西州的普林斯顿究竟是晴天还是雨天。正午时分，传感器之间的距离会掩盖计算机无法知道的波动、任何偏平均值的变化。到12：01时，那些波动就已经会在1英尺远的地方造成偏差。很快这种偏差会增加到尺10英的范围，如此等等，一直到全球的范围。
Lesson 15
Secrecy in industry
工业中的秘密
First listen and then answer the following question.
Why is secrecy particularly important in the chemical industries?
Two factors weigh heavily against the effectiveness of scientific research in industry. One is the general atmosphere of secrecy in which it is carried out, the other the lack of freedom of the individual research worker. In so far as any inquiry is a secret one, it naturally limits all those engaged in carrying it out from effective contact with their fellow scientists either in other countries or in universities, or even, often enough, in other departments of the same firm. The degree of secrecy naturally varies considerably. Some of the bigger firms are engaged in researches which are of such general and fundamental nature that it is a positive advantage to them not to keep them secret. Yet a great many processes depending on such research are sought for with complete secrecy until the stage at which patents can be taken out. Even more processes are never patented at all but kept as secret processes. This applies particularly to chemical industries, where chance discoveries play a much larger part than they do in physical and mechanical industries. Sometimes the secrecy goes to such an extent that the whole nature of the research cannot be mentioned. Many firms, for instance, have great difficulty in obtaining technical or scientific books from libraries because they are unwilling to have names entered as having taken out such and such a book, for fear the agents of other firms should be able to trace the kind of research they are likely to be undertaking.
J.D. BERNAL The Social Function of Science
New words and expressions
secrecy
n. 秘密
effectiveness
n. 成效，效力
inquiry
n. 调查研究
positive
process
n. 过程
patent
n. 专利；
v. 得到专利权
agent
n. 情报人员
有两个因素严重地妨碍工业中科学研究的效率：一是科研工作中普遍存在的保密气氛；二是研究人员缺乏个人自由。任何一项研究都涉及到保密，那些从事科研的人员自然受到了限制。他们不能和其他国家、其他大学、甚至往往不能与本公司的其他部门的同行们进行有效的接触。保密程度自然差别很大。某些大公司进行的研究属于一般和基础的研究，因此不保密对他们才有利。然而，依赖这种研究的很多工艺程序是在完全保密的情况下进行的，直到可以取得专利权的阶段为止。更多的工艺过程根本就不会取得专利权，而是作为秘方保存着。在这化学工业方面尤为突出。同物理和机械工业相比，化学工业中偶然发现的机会要多得多。有时，保密竟达到了这样的程度，即连研究工作的整个性质都不准提及。比如，很多公司向图书馆借阅科技书籍时感到困难，因为它们不愿让人家记下它们公司的名字和借阅的某一本书。他们生怕别的公司的情报人员据此摸到他们可能要从事的某项科研项目。
Lesson 16
The modern city
现代城市
First listen and then answer the following question.
What is the author's main argument about the modern city?
In the organization of industrial life the influence of the factory upon the physiological and mental state of the workers has been completely neglected. Modern industry is based on the conception of the maximum production at lowest cost, in order that an individual or a group of individuals may earn as much money as possible. It has expanded without any idea of the true nature of the human beings who run the machines, and without giving any consideration to the effects produced on the individuals and on their descendants by the artificial mode of existence imposed by the factory. The great cities have been built with no regard for us. The shape and dimensions of the skyscrapers depend entirely on the necessity of obtaining the maximum income per square foot of ground, and of offering to the tenants offices and apartments that please them. This caused the construction of gigantic buildings where too large masses of human beings are crowded together. Civilized men like such a way of living. While they enjoy the comfort and banal luxury of their dwelling, they do not realize that they are deprived of the necessities of life. The modern city consists of monstrous edifices and of dark, narrow streets full of petrol fumes and toxic gases, torn by the noise of the taxicabs, lorries and buses, and thronged ceaselessly by great crowds. Obviously, it has not been planned for the good of its inhabitants.
ALEXIS CARREL Man, the Unknown
New words and expressions 生词和短语
physiological
maximum
consideration
n. 考虑
descendant
n. 子孙，后代
artificial
n. 人工的
impose
v. 强加
dimension
n. 直径
skyscraper
n. 摩天大楼
tenant
n. 租户
civilized
banal
luxury
n. 豪华
deprive
v. 剥夺
monstrous
edifice
n. 大厦
toxic
ceaselessly
throng
v. 挤满，壅塞
在工业生活的组织中，工厂对工人的生理和精神状态的影响完全被忽视了。现代工业的基本概念是：以最低成本获取最多产品，为的是让某个个人或某一部分人尽可能多地赚钱。现代工业发展起来了，却根本没想到操作机器的人的本质。工厂把一种人为的生存方式强加给工人，却不顾及这种生存方式给工人及其后代带来的影响。大城市的建设毫不关心我们。摩天大楼完全是按这样的需要修建的：每平方英尺地皮取得最大收入和向租房人提供使他满意的办公室和住房。这样就导致了许多摩天大厦拔地而起，大厦内众多的人挤地一起。文明人喜欢这样一种生活方式。在享受自己住宅的舒适和庸俗的豪华时，却没有意识到被剥夺了生活所必需的东西。大得吓人的高楼和阴暗狭窄的街道组成了今日现代化的城市。街道上充斥着汽油味和有毒气体，出租汽车、卡车、公共汽车的噪音刺耳难忍，络绎不绝的人群挤来挤去。显然，现代化的城市不是这居民的利益而规划的。
Lesson 17
人为的疾病
First listen and then answer the following question.
What factor helped to spread the disease of myxomatosis?
In the early days of the settlement of Australia, enterprising settlers unwisely introduced the European rabbit. This rabbit had no natural enemies in the Antipodes, so that it multiplied with that promiscuous abandon characteristic of rabbits. It overran a whole continent. It caused devastation by burrowing and by devouring the herbage which might have maintained millions of sheep and cattle. Scientists discovered that this particular variety of rabbit (and apparently no other animal) was susceptible to a fatal virus disease, myxomatosis. By infecting animals and letting them loose in the burrows, local epidemics of this disease could be created. Later it was found that there was a type of mosquito which acted as the carrier of this disease and passed it on to the rabbits. So while the rest of the world was trying to get rid of mosquitoes, Australia was encouraging this one. It effectively spread the disease all over the continent and drastically reduced the rabbit population. It later became apparent that rabbits were developing a degree of resistance to this disease, so that the rabbit population was unlikely to be completely exterminated. There were hopes, however, that the problem of the rabbit would become manageable.
Ironically, Europe, which had bequeathed the rabbit as a pest to Australia, acquired this man-made disease as a pestilence. A French physician decided to get rid of the wild rabbits on his own estate and introduced myxomatosis. It did not, however, remain within the confines of his estate. It spread through France, Where wild rabbits are not generally regarded as a pest but as sport and a useful food supply, and it spread to Britain where wild rabbits are regarded as a pest but where domesticated rabbits, equally susceptible to the disease, are the basis of a profitable fur industry. The question became one of whether Man could control the disease he had invented.
RITCHIE CALDER Science Makes Sense
New words and expressions 生词和短语
settlement
n. 新拓居地
enterprising
settler
n. 移居者
Antipodes
n. 新西兰和澳大利亚（英）
promiscuous
abandon
n. 放任，纵情
overrun
v. 蔓延，泛滥
devastation
n. 破坏，劫掠
burrow
v. 挖、掘
susceptible
virus
n. 病毒
myxomatosis
n. 多发性粘液瘤
infect
v. 传染
epidemic
n. 流行病
mosquito
n. 蚊虫
carrier
n. 带菌者
exterminate
v. 消灭
ironically
bequeath
v. 把...传给
pest
n. 害虫，有害动物
pestilence
n. 瘟疫
confine
n. 范围
domesticate
v. 驯养
在澳大利亚移民初期，一些有创业精神的移民不明智地把欧洲兔子引进了澳大利亚。这种兔子在澳大利亚及新西兰没有天敌，因此便以兔子所特有的杂乱交配迅猛繁殖起来。整个澳洲兔子成灾。它们在地下打洞，吃掉本可以饲养数百万头牛羊的牧草，给澳洲大陆造成了毁灭性的破坏。科学家们发现，这种特殊品种的兔子（显然不包括别的动物）易患一种叫“多发性粘液瘤”的致命毒性疾病。通过让染上此病的动物在洞内乱跑，就可以使这种疾病在一个地区蔓延起来。后来又发现，有一种蚊子是传播这种疾病的媒介，能把此病传染给兔子。因此，世界上其他地方在设法消灭蚊子的时候，澳大利亚却在促使这种蚊子大量繁殖。蚊子把这种疾病扩散到整个澳洲大陆，效果甚佳，结果兔子的数目在为减少。后来，明显看出，兔子对这种疾病已产生了一定程度的免疫力，所以兔子不可能被完全消灭。但是，已有希望解决兔子所带来的问题。
具有讽刺意味的是，欧洲把这种兔子作为有害动物传给澳洲，而欧洲自己却染上了这种人为的瘟疫般的疾病。一位法国内科医生决定除掉自己庄园内的野兔子，于是引进了这种多发性粘液瘤疾病。然而，这种疾病并未被局限在他的庄园内，结果在整个法国蔓延开来。野兔在法国一般不被当作有害动物，而被视为打猎取乐的玩物和有用的食物来源。这种疾病又蔓延到了英国。在英国，野兔被当作有害的动物，可是家兔是赚钱的毛皮工业的基础，然而家兔同样易感染这种疾病。现在的问题是，人类能否控制住这种人为的疾病。
Lesson 18
Porpoises
海豚
First listen and then answer the following question.
What would you say is the main characteristic of porpoises?
There has long been a superstition among mariners that porpoises will save drowning men by pushing them to the surface, or protect them from sharks by surrounding them in defensive formation. Marine Studio biologists have pointed out that, however intelligent they may be, it is probably a mistake to credit dolphins with any motive of lifesaving. On the occasions when they have pushed to shore an unconscious human being they have much more likely done it out of curiosity or for sport, as in riding the bow waves of a ship. In 1928 some porpoises were photographer working like beavers to push ashore a waterlogged mattress. If, as has been reported, they have protected humans from sharks, it may have been because curiosity attracted them and because the scent of a possible meal attracted the sharks. Porpoises and sharks are natural enemies. It is possible that upon such an occasion a battle ensued, with the sharks being driven away or killed.
Whether it be bird, fish or beast, the porpoise is intrigued with anything that is alive. They are constantly after the turtles, who peacefully submit to all sorts of indignities. One young calf especially enjoyed raising a turtle to the surface with his snout and then shoving him across the tank like an aquaplane. Almost any day a young porpoise may be seen trying to turn a 300-pound sea turtle over by sticking his snout under the edge of his shell and pushing up for dear life. This is not easy, and may require two porpoises working together. In another game, as the turtle swims across the oceanarium, the first porpoise swoops down from above and butts his shell with his belly. This knocks the turtle down several feet. He no sooner recovers his equilibrium than the next porpoise comes along and hits him another crack. Eventually the turtle has been butted all the way down to the floor of the tank. He is now satisfied merely to try to stand up, but as soon as he does so a porpoise knocks him flat. The turtle at last gives up by pulling his feet under his shell and the game is over.
RALPH NADING HILL Window in the Sea
New words and expressions 生词和短语
porpoise
n. 海豚
mariner
n. 水手
shark
n. 鲨鱼
formation
n. 队形
dolphin
n. 海豚科动物
unconscious
beaver
n. 海狸
ashore
waterlogged
scent
n. 香味
ensue
v. 接着发生
intrigue
v. 引起兴趣
indignity
n. 侮辱
snout
n. 口鼻部
shove
v. 硬推
aquaplane
n. 驾浪滑水板
oceanarium
n. 水族馆
swoop
v. 猛扑
belly
n. 腹部
equilibrium
n. 平衡
butt
v. 碰撞
crack
n. 重击
长期以来，海员中流传着一种迷信的说法，认为海豚会把快要淹死的人托到水面，救人性命；或在人们周围列队保护，使他们免遭鲨鱼伤害。海洋摄影室的生物学家指出，无论海豚多么聪明，认为它们有救人的动机可能是错误的。当它们偶尔把一个失去知觉的人推到岸边时，更大的可能是出于好奇或游戏，就像它们追逐被船首犁开的浪花一样。1928年，有人拍摄到了海豚像海狸一样把浸透水的床垫推上岸的情景。正如报道中所说，如果海豚保护人不受鲨鱼侵害，那么它们可能是出于好奇；而鲨鱼可能是闻到了可以美食一顿的香味。海豚和鲨鱼是天然仇敌，双方可能随之发生搏斗，搏斗结果是海豚赶走或咬死鲨鱼。
海豚对凡是活的东西都感兴趣，不管是鸟、是鱼，还是野兽。它们经常追逐海龟，海龟则温顺地忍受着各种侮辱。一只小海豚特别喜欢用鼻子把海龟推到水面，然后像滑水板一样把海龟从水池的这一边推到那一边。几乎每天都可以看到一只小海豚把鼻子顶入一只300磅重的海龟的硬壳下面，拼命地把它翻过来。这并非易事，可能需要两只海豚合伙干才行。在另一场游戏中，当海龟游过水族馆时，第一只海豚从上方猛扑下去，用腹部撞击龟壳。这一下子把海龟撞下去好几英尺。海龟刚恢复平衡，第二只海豚又冲过来猛击一下。这只海龟最终被撞到池底。此时的海龟，只要能站起来就满足了，但它刚站起来，就被一只海豚击倒。海龟终于屈服了，将4条腿缩进壳内。游戏到此结束。
Lesson 19
The stuff of dreams
话说梦的本质
First listen and then answer the following question.
What is going on when a person experiences rapid eye-movements during sleep?
It is fairly clear that sleeping period must have some function, and because there is so much of it the function would seem to e important. Speculations about is nature have been going on for literally thousands of years, and one odd finding that makes the problem puzzling is that it looks very much as if sleeping is not simply a matter of giving the body a rest. 'Rest', in terms of muscle relaxation and so on, can be achieved by a brief period lying, or even sitting down. The body's tissues are self-repairing and self-restoring to a degree, and function best when more or less continuously active. In fact a basic amount of movement occurs during sleep which is specifically concerned with preventing muscle inactivity.
If it is not a question of resting the body, then perhaps it is the brain that needs resting? This might be a plausible hypothesis were it not for two factors. First the electroencephalograph (which is simply a device for recording the electrical activity of the brain by attaching electrodes to the scalp) shows that while there is a change in the pattern of activity during sleep, there is no evidence that the total amount of activity is any less. The second factor is more interesting and more fundamental. Some years ago an American psychiatrist named William Dement published experiments dealing with the recording of eye-movements during sleep. He showed that the average individual's sleep cycle is punctuated with peculiar bursts of eye-movements, some drifting and slow, others jerky and rapid. People woken during these periods of eye-movements generally reported that they had been dreaming. When woken at other times they reported no dreams. If one group of people were disturbed from their eye-movement sleep for several nights on end, and another group were disturbed for an equal period of time but when they were no exhibiting eye-movements, the first group began to show some personality disorders while the others seemed more or less unaffected. The implications of all this were that it was not the disturbance of sleep that mattered, but the disturbance of dreaming.
CHRISTOPHER EVANS The stuff of dreams from The Listener
New words and expressions 生词和短语
speculation
n. 推测
literally
odd
tissue
n. 组织
plausible
hypothesis
n. 假说
electroencephalograph
n. 脑电图仪
electrode
n. 电极
scalp
n. 头皮
psychiatrist
n. 精神病学家
punctuate
v. 不时介入
jerky
disorder
n. 失调
implication
n. 表明
很清楚，睡眠必然具有某种作用。睡眠占去那么多时间，所以其作用似乎还是很重要。人们对睡眠作用的种种猜测，确实有数千年之久。一项使人对这个问题感到困惑的奇怪的发现是，睡眠在很大程度似乎并不仅仅是为了使身体得到休息。“休息”，从使肌肉得到放松等方面来看，只要稍微躺一躺，甚至坐一坐就能达到。人体组织在一定程度上有自我修补和自我恢复的能力，有张有弛地连续活动时，其功能最佳。事实上，睡眠状态下仍有着基本的活动量，以防止肌肉活动停止。
如果睡眠的功能不是在于使身体得到休息，那么也许是让大脑得以休息？若不是下面两点，这种假使似乎是有道理的。第一点，脑电图记录仪（不过是一种把电极接到头皮上记录脑电活动的仪器）显示，人在睡眠时大脑活动的方式有变化，但没有迹象表明，其活动总量有任何减少。第二点更有意思，也更重要。前些年，美国一位精神病学者发表了一篇报告，报告中记录了眼球在睡眠时的活动情况。他指出，平常人的睡眠周期中不时伴有一阵阵奇怪的眼球队活动，这些活动有的飘忽而缓慢，有的急剧而快速。在眼球活动期间被叫醒的人都说自己在做梦；在其他期间叫醒他们，则说没有做梦。如果有两组人，一组人连续几夜在眼球队活动时被叫醒；另一组人也是连续几夜被叫醒，但是在眼球队没活动时被叫醒的。结果，第一组人开始出现性格失常，而第二组人似乎没受什么影响。这一切暗示我们：睡眠受到干忧没关系，而做梦受到干忧是有问题的。
Lesson 20
Snake poison
蛇毒
First listen and then answer the following question.
What are the two different ways in which snake poison acts?
How it came about that snakes manufactured poison is a mystery. Over the periods their saliva, a mild, digestive juice like our own, was converted into a poison that defies analysis even today. It was not forced upon them by the survival competition; they could have caught and lived on prey without using poison, just as the thousands of non-poisonous snakes still do. Poison to a snake is merely a luxury; it enables it to get its food with very little effort, no more effort than one bite. And why only snakes? Cats, for instance, would be greatly helped; no running fights with large, fierce rats or tussles with grown rabbits -- just a bite and no more effort needed. In fact, it would be an assistance to all carnivores though it would be a two-edged weapon when they fought each other. But, of the vertebrates, unpredictable Nature selected only snakes (and one lizard). One wonders saliva into why Nature, with respect from that of others, as other on the blood.
In the conversion of saliva into poison, one might suppose that a fixed process took place. It did not; some snakes manufacture a poison different in every respect from that of others, as different as arsenic is from strychnine, and having different effects. One poison acts on the nerves, the other on the blood.
The makers of the nerve poison include the mambas and the cobras and their venom is called neurotoxic. Vipers (adders) and rattlesnakes manufacture the blood poison, which is known as haemolytic. Both poisons are unpleasant, but by far the more unpleasant is the blood poison. It is said that the nerve poison is the more primitive of the two, that the blood poison is, so to speak, a newer product from an improved formula. Be that as it may, the nerve poison does its business with man far more quickly than the blood poison. This, however, means nothing. Snakes did not acquire their poison for use against man but for use against prey such as rats and mice, and the effects on these of viperine poison is almost immediate.
JOHN CROMPTON The snake
New words and expressions 生词和短语
saliva
n. 唾液
digestive
defy
v. 使不可能
analysis
n. 分析
prey
n. 被捕食的动物
fierce
tussle
n. 扭打
carnivore
n. 食肉动物
vertebrate
n. 脊椎动物
lizard
n. 蜥蜴
concoct
v. 调制
potency
n. 效力
conversion
n. 转变
arsenic
n. 砒霜
strychnine
n. 马钱子碱
mamba
n. 树眼镜蛇
cobra
n. 眼镜蛇
venom
n. 毒液
neurotoxic
viper
n. 蝰蛇
n. 蝮蛇
rattlesnake
n. 响尾蛇
haemolytic
viperine
蛇是怎样产生毒液的，这是一个谜。蛇的唾液本来和我们人的消化液一样柔和，但经过漫长的时间，演变成了今天仍无法分析清楚的毒液。毒液不是生存竞争强加给它们的，它们也可以不用毒液捕捉动物而生存，就像今天成千上万的无毒蛇那样。毒液对毒蛇来说只不过是一种舒适生存的优越手段，它使蛇不用费多大力气就能捕获到食物，轻咬一口即可。为什么只有蛇才有毒液呢？譬如说，如果猫有毒液，那对猫会大有帮助，它就不必再和又大又凶的老鼠边跑边博斗了，也不必再和大兔子扭斗了，只要咬一口，就不必再费大力气。因此，任何食肉动物有了毒液，都能从中获益。不过，当它们相互撕打时，毒液就成了利弊参半的武，可以杀死对方，也可以被对方的毒液杀死。然而，在脊椎动物中，大自然神秘模测地只选择了蛇（还有一种蜥蜴），人们弄不清楚大自然为什么在某些蛇的身上调制出如此高效的毒液来。
人们可能认为，唾液转变成毒液，其中有固定的程序。其实没有。有些蛇产生的毒液也在各方面与另外一些毒蛇产生的毒液不同，就像砒霜不同于马钱子碱一样。不同毒蛇产生的毒液产生的效果不同，一种毒液作用于神经，另一种毒液作用于血液。
产生神经毒液的蛇有一种非洲树眼镜蛇和眼镜蛇，它们的毒液称为神经毒素。蝰蛇（蝮蛇）和响尾蛇产生血液毒素，称为溶血性毒液。这两种毒液都很可怕，但溶血性毒液尤其厉害。据说，神经毒液在两种毒液中是较为原始的一种，而溶血性毒液，打个比方说，是根据改良配方生产的一种较新的产品。不过，神经毒辣液比溶血性毒液在人身上起作用快得多。但是，这没有什么关系，因为蛇有毒液不是用来对付人的，而是对付它的猎物，诸如鼠类，毒液对这些猎物会立刻起作用。
Lesson 21
William S. Hart and
the early 'Western' film
威廉.S. 哈特和早期限的‘西部’影片
First listen and then answer the following question.
How did William Hart's childhood prepare him for his acting role in Western films?
William S. hart was, perhaps, the greatest of all Western stars, fro unlike Gary Cooper and John Wayne he appeared in nothing but Westerns. From 1914 to 1924 he was supreme and unchallenged. It was Hart who created the basic formula of the Western film, and devised the protagonist he played in every film he made, the good-had man, the accidental-noble outlaw, or the honest-but-framed cowboy, or the sheriff made suspect by vicious gossip; in short, the individual in conflict with himself and his frontier environment.
Unlike most of his contemporaries in Hollywood, Hart actually knew something of the old West. He had lived in it as a child when it was already disappearing, and his hero was firmly rooted in his memories and experiences, and in both the history and the mythology of the vanished frontier. And although no period or place in American history has been more absurdly romanticized, myth and reality did join hands in at least one arena, the conflict between the individual and encroaching civilization.
Men accustomed to struggling for survival against the elements and Indians were bewildered by politicians, bankers and businessmen, and unhorsed by fences, laws and alien taboos. Hart's good-bad man was always an outsider, always one of the disinherited, and if he found it necessary to shoot a sheriff or rob a bank along the way, his early audiences found it easy to understand and forgive, especially when it was Hart who, in the end, overcame the attacking Indians.
Audiences in the second decade of the twentieth century found it pleasant to escape to a time when life, though hard, was relatively simple. We still do; living in a world in which undeclared aggression, war, hypocrisy, chicanery, anarchy and impending immolation are part of our daily lives, we all want a code to live by.
CARL FOREMAN Virtue and a Fast Gun from The Observer
New words and expressions 生词和短语
Supreme
protagonist
n. 主角
outlaw
n. 逃犯，亡命之徒
framed
vicious
mythology
n. 神话
vanished
absurdly
arena
n. 竞技场在
encroaching
Indian
n. 印第安人
bewilder
v. 使手足无措
alien
taboo
n. 戒律
disinherit
v. 剥夺...继承权
undeclared
hypocrisy
n. 伪善
chicanery
n. 诈骗
impending
immolation
n. 杀戮
code
n. 准则
威廉.S.哈特大概是美国西部电影明星中的佼佼者。他和加里.古柏、约翰.韦恩不同，他只在西部电影中扮演角色。在1914年至1924年期间，他首屈一指，独霸影坛。正是他创造了西部电影的基调，即在他自己的拍摄的影片中他所塑造的主人公形象：被认为是坏人的好人，出人意料的高尚的逃犯，诚实却遭陷害的牛仔或因流言蜚语蒙受嫌疑的司法官。总之，主人公是一个自相矛盾，又与他的拓荒环境相矛盾的人物。
哈特与大部分同时代在好莱坞的演员不同，他确实了解西部早期拓荒生活的一些情况。作为一个孩子他曾在西部生活过，当时西部拓荒生活正在消失。他塑造的英雄人物深深地扎根于他本人的记忆和经历之中，也扎根于有关已经消失的拓荒生活的历史和神话之中。虽然在美国历史上没有任何时期或地区像西部拓荒时期那样被荒谬地浪漫主义化了，但神话和事实至少在某一个舞台上共存，也就是存在于个人与渐渐闯入的文明这两者的冲突之中。
习惯与大自然和印第安人作斗争以求生存的拓荒者被政客、银行家和商人搞得晕头转向，最后被圈地、尖律我外来的清规戒律所击败。哈特扮演的被误为坏人的好人总是一个局外人，总是一个被剥夺继承权的人。如果他认为在进行过程中有必要枪击一个司法官或抢劫一个银行，他的早期观众很容易接受，觉得应该原谅他，特别是当哈特最后战胜了前来进攻的印第安人时，观众更能原谅他。
生活在20世纪20年代的观众认为，逃到一个即使艰苦但比较简朴的时代中去是件愉快的事，我们今天仍有这种感觉。如今，不宣而战的侵略、战争、虚伪、诈骗、无政府状态以及即将临头的毁灭成了我们日常生活的一部分，我们都希望有一个赖以生存的行为准则。
Lesson 22
Knowledge and progress
知识和进步
First listen and then answer the following question.
In what two areas have people made no 'progress' at all?
Why does the idea of progress loom so large in the modern world? Surely progress of a particular kind is actually taking place around us and is becoming more and more manifest. Although mankind has undergone no general improvement in intelligence or morality, it has made extraordinary progress in the accumulation of knowledge. Knowledge began to increase as soon as the thoughts of one individual could be communicated to another by means of speech. With the invention of writing, a great advance was made, for knowledge could then be not only communicated but also stored. Libraries made education possible, and education in its turn added to libraries: the growth of knowledge followed a kind of compound interest law, which was greatly enhanced by the invention of printing. All this was comparatively slow until, with the coming of science, the tempo was suddenly raised. Then knowledge began to be accumulated according to a systematic plan. The trickle became a stream; the stream has now become a torrent. Moreover, as soon as new knowledge is acquired, it is now turned to practical account. What is called 'modern civilization' is not the result of a balanced development of all man's nature. but of accumulated knowledge applied to practical life. The problem now facing humanity is: What is going to be done with all this knowledge? As is so often pointed out, knowledge is a two-edged weapon which can be used equally for good or evil. It is now being used indifferently for both. Could any spectacle, for instance, be more grimly whimsical than that of gunners ourselves very seriously what will happen if this twofold use of knowledge, with its ever-increasing power, continues.
G.N.M.TYRRELL The Personality of Man
New words and expressions 生词和短语
loom
v. 赫然耸起
manifest
morality
n. 道德
communicate
v. 交流，交际
compound
enhance
v. 增进
tempo
n. 速率
trickle
n. 涓涓细流
torrent
n. 滔滔洪流
humanity
n. 人类
indifferently
grimly
whimsical
shatter
v. 毁坏
twofold
为什么进步这个概念在现代世界显得如此突出？无疑是因为有一种特殊的进步实际上正在我们周围发生，而且变得越来越明显。虽然人类有智力和道德上没有得到普遍提高，但在知识积累方面却取得了巨大的进步。人一旦能用语言同别人交流思想，知识的积累便开始了。随着书写的发明，又迈进了一大步，因为这样一来，知识不仅能交流，而且能储存了。藏书使教育成为可能，而教育反过来又丰富了藏书，因为知识的增长遵循着一种“滚雪球”的规律。印刷术的发明又大大提高了知识增长的速度。所有这些发展都比较缓慢，而随着科学的到来，增长的速度才突然加快。于是，知识便开始有系统有计划地积累起来。涓涓细流汇成小溪，小溪现已变成了奔腾的江河。而且，新知识一旦获得，便得到实际应用。所谓“现代文明”并不是人的天性平衡发展的结果，而是积累起来的知识应用到实际生活中的结果。现在人类面临的问题是：用这些知识去做什么？正像人们常常指出的，知识是一把双刃刀，可以用于造福，也可以用来为害。人们现在正漫不经心地把知识用于这两个方面，例如：炮兵利用科学毁坏人的身体、而外科医生就在附近用科学抢救被炮兵毁坏的人体，还有什么情景比这更可怕、更怪诞的吗？我们不得不严肃地问问我们自己：随着日益增长的知识的力量，如果我们继续利用知识的这种双重性，将会发生什么样的情况呢？
Lesson 23
Bird flight
鸟的飞行方法
First listen and then answer the following question.
What are the two main types of bird flight described by the author?
No two sorts of birds practise quite the same sort of flight; the varieties are infinite; but two classes may be roughly seen. Any shi that crosses the Pacific is accompanied for many days by the smaller albatross, Which may keep company with the vessel for an hour without visible or more than occasional movement of wing. The currents of air that the walls of the ship direct upwards, as well as in the line of its course, are enough to give the great bird with its immense wings sufficient sustenance and progress. The albatross is the king of the gliders, the class of fliers which harness the air to their purpose, but must yield to its opposition. In the contrary school, the duck is supreme. It comes nearer to the engines with which man has 'conquered' the air, as he boasts. Duck, and like them the pigeons, are endowed with such-like muscles, that are a good part of the weight of the bird, and these will ply the short wings with such irresistible power that they can bore for long distances through an opposing gale before exhaustion follows. Their humbler followers, such as partridges, have a like power of strong propulsion, but soon tire. You may pick them up in utter exhaustion, if wind over the sea has driven them to a long journey. The swallow shares the virtues of both schools in highest measure. It tires not, nor does it boast of its power; but belongs to the air, travelling it may be six thousand miles to and from its northern nesting home, feeding its flown young as it flies, and slipping through we no longer take omens from their flight on this side and that; and even the most superstitious villagers no longer take off their hats to the magpie and wish it good-morning.
WILLIAM BEACH THOMAS A Countryman's Creed
New words and expressions 生词和短语
albatross
n. 信天翁
sustenance
n. 支撑力
glider
n. 滑翔者
harness
v. 利用
endow
v. 赋有
ply
v. 不断地供给
gale
n. 大风
partridge
n. 鹧鸪
like
propulsion
n. 推进力
utter
slip
v. 滑行
omen
n. 预兆
没有任何两种鸟的飞行方式是相同的。鸟的飞行方式千差万别，但大体上可分为两类。任何一艘横度太平洋的轮船都会有一种小信天翁伴随飞行许多天。它们随船飞行一小时也难得见其扇动一下翅膀。沿船体的上升的气流和沿航线向前的气流给这种巨翼大鸟以足够的浮力和推力。信天翁是滑翔飞行的鸟类之王，它能自如地驾驭空气，但必须顺气流飞行。与滑翔鸟相对的另一类鸟中，数野鸭本领最高。它更近乎于人类自夸的“征服”了空气的发动机。野鸭及它们相似的鸽子有天赋的钢铁般的肌肉，占了体重的很大一部分。这些肌肉以巨大的力量扇动短小的翅膀，使这类鸟能顶着大风飞行很远的路才会疲劳。次于野鸭和鸽子的鸟，如鹧鸪，有相似的巨大推动力，但很快会疲劳。如果海风驱使它们飞行很长距离，你可以捡到一些因筋疲力尽而摔下来的鹧鸪。燕子充分兼有这两类鸟的长处，它既不疲劳，也不炫耀自己的飞翔力；在空中十分自如，可以飞行6，000英里，可以飞往北方做窝的老家，再从老家飞回；一边飞一边喂养会飞的雏燕，甚至在顶风时也能在气流中滑翔，似乎气流在帮它前进。这些鸟对我们是有益的，虽然我们不再从它们的飞翔姿态来占卜吉凶，连最迷信的村民也不再对喜鹊脱帽行礼，祝它早安了。
Lesson 24
Beatuy
美
First listen and then answer the following question.
What do glimpses of beauty, either in nature or art, often suggest to the human mind?
A young man sees a sunset and, unable to understand or to express the emotion that it rouses in him, concludes that it must be the gateway to world that lies beyond. It is difficult for any of us in moments of intense aesthetic experience to resist the suggestion that we are catching a glimpse of a light that shines down to us from a different realm of existence, different and, because the experience is intensely moving, in some way higher. And, though the gleams blind and dazzle, yet do they convey a hint of beauty and serenity greater than we have known or imagined. Greater too than we can describe; for language, which was invented to convey the meanings of this world, cannot readily be fitted to the uses of another.
That all great has this power of suggesting a world beyond is undeniable. In some moods, Nature shares it. There is no sky in June so blue that it does not point forward to a bluer, no sunset so beautiful that it does not waken the vision of a greater beauty, a vision which passes before it is fully glimpsed, and in passing leaves and indefinable longing and regret. But, if this world is not merely a bad joke, life a vulgar flare amid the cool radiance of the stars, and existence an empty laugh braying across the mysteries; if these intimations of a something behind and beyond are not evil humour born of indigestion, or whimsies sent by the devil to mock and madden us. if, in a word, beauty means something, yet we must not seek to interpret the meaning. If we glimpse the unutterable, it is unwise to try to utter it, nor should we seek to invest with significance that which we cannot grasp. Beauty in terms of our human meanings is meaningless.
C.E.M.JOAD Pieces of Mind
New words and expressions 生词和短语
intense
aesthetic
realm
n. 世界
serenity
n. 静谧
undeniable
indefinable
vulgar
n. 发光
intimation
n. 暗示
unutterable
invest
v. 赋予
一个年轻人看到日落，由于无法理解和表达日落在他心中唤起的激情，便得出结论：日落处想必是通往遥远世界的大门。无论是谁，在强烈感受到美的时刻，心中都不禁油生一种遐想：我们似乎瞥见从另一个世界射向我们的一线光芒，那个世界不仅不同于我们这个世界，而且由于美感的强烈感染，在某些方面比我们这个世界更美好。虽然这光芒令人眼花缭乱，但它确实给予我们一种不曾经历和无法想象的美感和静谧的启示。这种美感和静谧是我们无法描述的，因为我们发明的语言是用来描述这个世界的含义，不能随便拿来去描述另一个世界。
不可否认，一切伟大的艺术都具有使人遐想到进入天外世界的魅力。在某种状态下，大自然也有这种魅力。六月蔚蓝的天空总使人遥想一个更加蔚蓝的苍穹；美丽的落日总会引起一个更加绚丽的景象未及饱览便一闪即逝，并在消逝中给人留下不可名状的渴望和惆怅。如果这个世界不只是一个拙劣的恶作剧，如果人生不只是群星寒光中平凡的一闪，如果存在不只是对神秘事物的一种空虚的笑声，如果某种玄妙事物的暗示不是消化不良引起的邪恶情绪，也不是魔鬼为了捉弄我们，使我们发狂而送给我们的邪念，一句话，如果美有某种意义的话，我闪千万不要去阐明它的意义。如果我瞥见了只可意会不可言传的事物，企图把它说出来，那上不明智的；对于我们不理解的事物，我们也不应该去赋予它某种意义。用对我们人类有意义的词解释美是没有意义的。
Lesson 25
Non-auditory effects of noise
噪音的非听觉效应
First listen and then answer the following question.
What conclusion does the author draw about noise and health in this piece?
May people in industry and the Services, who have practical experience of noise, regard any investigation of this question as a waste of time; they are not prepared even to admit the possibility that noise affects people. On the other hand, those who dislike noise will sometimes use most inadequate evidence to support their pleas for a quieter society. This is a pity, because noise abatement really is a good cause, and it is likely to be discredited if it gets to be associated with had science.
One allegation often made is that noise produces mental illness. A recent article in a weekly newspaper, for instance, was headed with a striking illustration of a lady in a state of considerable distress, with the caption 'She was yet another victim, reduced to a screaming wreck'. On turning eagerly to the text, one learns that the lady was a typist who found the sound of office typewriters worried her more and more until eventually she had to go into a mental hospital. Now the snag in this sort of anecdote is of course that one merely a symptom? Another patient might equally well complain that her neighbours were combining to slander her and persecute her, and yet one might be cautious about believing this statement.
What is needed in case of noise is a study of large numbers of people living under noisy conditions, to discover whether they are mentally ill more often than other people are. Some time ago the United States Navy, for instance, examined a very large number of men working on aircraft carriers: the study was known as Project Anehin. It can be unpleasant to live even several miles from an aerodrome; if you think what it must be like to share the deck of a ship with several squadrons of jet aircraft, you will realize that a modern navy is a good place to study noise. But neither psychiatric interviews nor objective tests were able to show any effects upon these American sailors. This result merely confirms earlier American and British studies: if there is any effect of noise upon mental health, it must be so small that present methods of psychiatric diagnosis cannot find it. That does not prove that it does exist: but it does mean that noise is less dangerous than, say, being brought up in an orphanage -- which really is mental health hazard.
D.E.BROADBENT Non-auditory effects of noise from Science Survey
New words and expressions 生词和短语
auditory
plea
n. 要求
abatement
n. 减少
discredit
v. 怀疑
allegation
n. 断言
caption
n. 插图说明
wreck
n. 残废人
snag
n. 疑难之处，障碍
anecdote
n. 轶闻
slander
v. 诽谤
persecute
v. 迫害
n. 中队
psychiatric
diagnosis
n. 诊所
orphanage
n. 孤儿院
在工业部门工作和在军队中服役的许多人对噪声音有切身的体会，他们认为对这个问题进行调查中浪费时间，甚至不愿承认噪音可能对人有影响。另一方面，那些讨厌噪音的人有时会用不充分的证据来支持他们希望有一个较为安静的社会环境的要求。要求减少噪音是件好事，但是如果与拙劣的科学掺杂在一起的话，就不会被人们所信任，这是很遗憾的。
常见的一种指责是，噪音能引起精神病。例如，最近一家周报刊登了一篇文章，文章上方有一幅引人注目的插图，是一位表情沮丧的女子。图的文字说明：“她是又一个受害者，成了只会尖叫的可怜虫。”当人们急切地看完正文后，便知道这女子是个打字员，办公室打字机的声音使她越来越烦，最终住进了精神病医院。这类奇闻的疑难之处是无法区别因果关系。是噪音引起了（精神）病呢，还是（精神）病的症状之一是对噪音的抱怨？另有一位病人可能同样有理由抱怨说，她的邻居们正在联合起来对她进行诽谤和迫害，不过，人们不会轻信她的抱怨。
对于噪音问题，需要对大量生活在噪音中的人进行研究，看一看他们是否比其他人更易患精神病。例如，美国海军前些时候调查了许多在航空母航上工作的人，这次调查被称之为：“安内英工程”。即使住在离机场几英里以外的地方，机场的噪音也会使人难受。因此，如果你能想像出和几个中队的喷气机同在一个甲板上是什么滋味儿的话，你就会认识到现代海军是研究噪音的好地方。但是，不管进行精神病学的调查访问，还是进行客观的测试，都不能显示噪音对这些美国水兵有任何影响。这个结果只不过证实了美国和英国早些时候的研究结论：如果噪音对精神健康有影响的话，那也一定是微乎其微，以致现代的精神病诊断方法还发现不了。这并不是证实不存在噪音对健康的影响。但它确实说明，噪音的危险性 -- 比如说 -- 比在孤儿院长大所受的危害要小一些，孤儿院才是真正危害精神健康的地方。
Lesson 26
The past life of the earth
地球上的昔日生命
First listen and then answer the following question.
What is the main condition for the preservation of the remains of any living creature?
It is animals and plants which lived in or near water whose remains are most likely to be preserved, for one of the necessary conditions of preservation is quick burial, and it is only in the seas and rivers, and sometimes lakes, where mud and sit have been continuously deposited, that bodies and the can be rapidly covered over and preserved.
But even in the most favourable circumstances only a small fraction of the creatures that die are preserved in this way before decay sets in or, even more likely, before scavengers eat them. After all, all living creatures live by feeding on something else, whether it be plant or animal, dead or alive, and it is only by chance that such a fate is avoided. The remains of plants and animals that lived on land are much more rarely preserved, for there is seldom anything to cover them over. When you think of the innumerable birds that one sees flying bout, not to mention the equally numerous small animals like field mice and voles which you do not see, it is very rarely that one comes across a dead body, except, of course, on the roads. They decompose and are quickly destroyed by the weather or eaten by some other creature.
It is almost always due to some very special circumstances that traces of land animals survive, as by falling into inaccessible caves, or into an ice crevasse, like the Siberian mammoths, when the whole animal is sometimes preserved, as in a refrigerator. This is what happened to the famous Beresovka mammoth which was found preserved and in good condition. In his mouth were the remains of fir trees -- the last meal that he had before he fell into the crevasse and broke his back. The mammoth has now just a suburb of Los Angeles. Apparently what happened was that water collected on these tar pits, and the bigger animals like the elephants ventured out on to the apparently firm surface to drink, and were promptly bogged in the tar. And then, when they were dead, the carnivores, like the sabre-toothed cats and the giant wolves, came out to feed and suffered exactly the same fate. There are also endless numbers of birds in the tar as well.
ERROL WHITE The past life of the earth from Discovery
New words and expressions 生词和短语
preservation
n. 保存
silt
n. 淤泥
scavenger
n. 食腐动物
vole
n. 野鼠，鼹鼠
decompose
v. 腐烂
inaccessible
crevasse
n. 缝隙
Siberian
palaeontological
St. Petersburg
n. 圣彼得堡
sabre-toothed
venture
v. 冒险
bogged
只有生活在水中或水边的动植物尸体最有可能被保存下来，因为保存的必要条件之一是迅速掩埋，所以只有在泥沙不停淤积的海洋和江河里，有时在湖泊里，尸体之类的东西才能被迅速地覆盖而保存下来。
即使是在最有利的环境中，死去的生物中也只有一小部分能在开始腐烂前，或更可能在被食腐动物吃掉之前，被这样保存下来。因为一切生物都是靠吃别的东西来活命的，不管这种东西是植物还是动物，死的还是活的，因此，生物偶尔才能避免被吃掉的命运。曾在陆地上生活过的动植物的遗体被保存下来的更为罕见，因为陆地上几乎没有什么东西覆盖它们。你可以想象出天上有看得见的飞来飞去、数不清的鸟，地上有不显眼的无数的老鼠和田鼠之类的小动物，但是，除非在路上，很少有人遇到这些动物的尸体，因为它们腐败之后很快就被风化掉，或被别的动物吃掉了。
几乎总是由于某些特殊的条件，陆地动物的遗体才被存下来，如掉进难以到达的洞穴，或掉进冰河裂缝里，或者像西伯利亚长毛象那样掉进冰窟中，有时整个动物像被放在冰箱里一样被保存下来，著名的那林索夫卡长毛象就是这样被保存下来的，而且保存得很好。它嘴里还留着冷杉 -- 它掉进冰河裂隙折断脊椎柱之前的最后一顿饭。这头长毛象已被修复，现存于圣彼得堡古生物学博物馆。有的动物掉进天然沥清坑里被保存下来，如在兰桥.拉.布里 -- 现在是洛杉矶的郊区发现的大象、剑齿虎和许多其他动物。显然，事情的经过是这样：沥青坑里积存了水，大象那样的大动物冒险到似乎坚固的水面上去饮水，立即掉进了沥青坑。大象死后，一些食肉动物，如剑齿虎和大灰狼就来吃大象，结果遭到了同样的命运。沥青坑里还有无数只鸟的尸体。
Lesson 27
The 'Vasa'
“瓦萨”号
First listen and then answer the following question.
What happened to the 'Vasa' almost immediately after she was launched?
From the seventeenth-century empire of Sweden, the story of a galleon that sank at the start of her maiden voyage in 1628 must be one of the strangest tales of the sea. For nearly three and a half centuries she lay at the bottom of Stockholm harbour until her discovery in 1956. This was the Vasa, royal flagship of the great imperial fleet.
King Gustavus Adolphus, 'The Northern Hurricane', then at the height of his military success in the Thirty Years' War, had dictated her measurements and armament. Triple gun-decks mounted sixty-four bronze cannon. She was intended to play a leading role in the growing might of Sweden.
As she was prepared of her maiden voyage on August 10, 1628, Stockholm was in a ferment. From the Skeppsbron and surrounding islands the people watched this thing of beauty begin to spread her sails and catch the wind. They had laboured for three years to produce this floating work of art; she was more richly carved and ornamented than any previous ship. The high stern castle was a riot of carved gods, demons, knights, kings, warriors, mermaids, cherubs; and zoomorphic animal shapes ablaze with rea and gold and blue, symbols of courage, power, and cruelty, were portrayed to stir the imaginations of the superstitious sailors of the day.
Then the cannons of the anchored warships thundered a salute to which the Vasa fired in reply. As the emerged from her drifting cloud of gun smoke with the water churned to foam beneath her bow, her flags colour, she presented a more majestic spectacle than Stockholmers had ever seen before. All gun-ports were open and the muzzles peeped wickedly from them.
As the wind freshened there came a sudden squall and the ship made a strange movement, listing to port. The Ordnance Officer ordered all the port cannon to be heaved to starboard to counteract the list, but the steepening angle of the decks increased. Then the sound of rumbling thunder reached the watchers on the shore, as cargo, ballast, ammunition and 400 people went sliding and crashing down to the port side of the steeply listing ship. The lower gun-ports were now below water and the inrush sealed the ship's fate. In that first glorious hour, the mighty Vasa, which was intended to rule the Baltic, sank with all flags flying-in the harbour of her birth.
ROY SAUNGERS The Raising of the 'Vasa' from The Listener
New words and expressions 生词和短语
galleon
n. 大型帆船
Stockholm
n. 斯德哥尔摩
flagship
n. 旗舰
imperial
hurricane
n. 飓风
armament
n. 军械
triple
mount
v. 架有
bronze
n. 青铜
cannon
n. 加农炮
1628年，一艘大帆船在处女航时就沉没了，这个从容不迫7世纪瑞典帝国流传至今的故事无疑是航海史上最离奇的事件之一。这艘大船在斯德哥尔摩港口的海底躺了将近几年来个世纪之后，直到1956年才被发现。这就是“瓦萨”号，帝国大舰的皇家旗舰。
当时号称“北方飓风”的国王古斯夫斯.阿道尔弗正处在“三十年战争”的军事鼎盛阶段，他亲自规定了这艘船的规模和武器配备。3层的火炮甲板上装着眼点4门青铜加农炮，目的就是要在不断增长的瑞典势力中起主导作用。
1628年8月10日，“瓦萨”号准备首航时，斯德哥尔摩一片欢腾。人们从斯开波斯布朗和周围的岛屿前来观着这艘美丽的战船扬帆起航，乘风前进。瑞典人辛辛苦苦干了3年才建成这件水上艺术品，它比以往任何船只雕刻得都更加精美，装饰得都更加华丽。高耸的船楼上雕刻了令人眼花缭乱的神仙、妖魔、骑士、国王、武士、美人鱼和小天使，还有用红色、金黄色、蓝色绘制的光彩夺目的兽形图案，象征着勇敢、力量和残暴，以激起汉时崇尚迷信的水手们的想像。
这时，停泊在港口的其他战船向“瓦萨”号鸣炮致礼，“瓦萨”号也鸣炮回礼。当“瓦萨”号从弥漫的礼炮烟云中出现时，船头下浪花加溅，舰旗迎风招展，三角旗随风飘动，微风鼓起风帆，金碧辉煌的船楼闪耀着灿烂的色彩。“瓦萨”号展现的壮观景象是斯德哥尔摩人从未见过的。船上的炮眼开着，炮口虎视眈眈地向外窥视着。
当风力增强时，突然刮来一阵大风，“瓦萨”号奇怪地摇晃了一下，便向左舷倾斜。炮长命令把左舷上所有大炮搬到右舷上来以抵消船的倾斜，但甲板的倾斜度仍在增加。当物口、压舱物、弹药和400个人轰地一声滑向陡斜的左舷时，岸上的观众听到了雷鸣般的轰响。下层炮眼已淹没在水里，涌进船舱的水给“瓦萨”号带来了难以逃脱的厄运。就这样，想要统治波罗的海的大型战舰“瓦萨”号，在它壮丽的起航时刻，带着全身飘扬的彩旗，沉没在了它诞生的港口。
Lesson 28
Patients and doctors
病人与医生
First listen and then answer the following question.
What are patients looking for when they visit the doctor?
This is a sceptical age, but although our faith in many of the things in which our forefathers fervently believed has weakened, our confidence in the curative properties of the bottle of medicine remains the same a theirs. This modern faith in medicines is proved the fact that the annual drug bill of the Health Services is mounting to astronomical figures and shows no signs at present of ceasing to rise. The majority of the patients attending the medical out-patients departments of our hospitals feel that they have not received adequate treatment unless they are able to carry home with them some tangible remedy in the shape of a bottle of medicine, a box of pills, or a small jar of ointment, and the doctor in charge of the department is only too ready to provide them with these requirements. There is no quicker method of disposing of patients then by giving them what they are asking for, and since most medical men in the Health Services are overworked and have little time for offering time-consuming and little-appreciated advice on such subjects as diet, right living, and the need for abandoning bad habits etc., the bottle, the box, and the jar are almost always granted them.
Nor is it only the ignorant and ill-educated person who was such faith in the bottle of medicine. It is recounted of Thomas Carlyle that when him in his pocket what remained of a bottle of medicine formerly prescribed for an indisposition of Mrs. Carlyle's. Carlyle was entirely ignorant of what the bottle in his pocket contained, of the nature of the illness from which his friend was suffering, and of what had previously been wrong with his wife, but a medicine that had worked so well in one form of illness would surely be of equal benefit in another, and comforted by the thought of the help he was bringing to his friend, he hastened to Henry Taylor's house. History does not relate whether his friend accepted his medical help, but in all probability he did. The great advantage of taking medicine is that it makes no demands on the taker beyond that of putting up for a moment with a disgusting taste, and that is what all patients demand of their doctors -- to be cured at no inconvenience to themselves.
New words and expressions 生词和短语
sceptical
forefathers
n. 祖先
fervently
curative
astronomical
tangible
remedy
n. 药物
ointment
n. 药膏
prescribe
v. 开药方
indisposition
n. 小病
inconvenience
n. 令人讨厌的
inconvenience
n. 不便
这是一个怀疑一切的时代，可是虽然我们对我们祖先笃信的许多事物已不太相信，我们对瓶装药品疗效的信心仍与祖辈一样坚定。卫生部门的处度药费上升到了天文数字，并且目前尚无停止上升的迹象，这个事实证实了现代人对药物的依赖。在医院门诊部看病的大多数人觉得，如果不能带回一些看得见、摸得着的药物，如一瓶药水，一盒药丸、一小瓶药膏回家的话，就没算得到了充分的治疗。负责门诊的医生也非常乐意为前来看病的人提供他们想要得到的药物，病人要什么就给什么，没有比这样处理病人更快的方法了。因为卫生部门的大多数医生超负荷工作，所以没有多少时间提出一些既费时而又不受人欢迎的忠告，如注意饮食、生活有规律，需要克服坏习惯等等，结果就是把瓶药、盒药、罐药开给看病的人而完事大吉。
并不只是那些无知和没受过良好教育的人才迷信药瓶子。据说托马斯.卡莱尔有过这么一件事：他听说朋友亨利.泰勒病了，就立刻跑去看他，衣袋里装上了他妻子不舒服时吃剩下的一瓶药。卡莱尔不知道药瓶子里装的是什么药，不知道他的朋友得的是什么病，也不知道妻子以前得的是什么病，只知道一种药对一种病有好处，肯定对另一种病也会有好处。想到能对朋友有所帮助，他感到很欣慰，于是急急忙忙来到了亨利.泰勒的家里，他的朋友是否接受了他的药物治疗，历史没有记载，但很可能接受了。服药的最大优点是：除了暂时忍受一下令人作呕的味道外，对服药人别无其他要求。这也正是病人对医生的要求 -- 病要治好，但不要太麻烦。
Lesson 29
The hovercraft
气垫船
First listen and then answer the following question.
What is a hovercraft riding on when it is in motion?
Many strange new means of transport have been developed in our century, the strangest of them being perhaps the hovercraft. In 1953, a former electronics engineer in his fifties, Christopher Cockerell, who had turned to boat-building on the Norfolk Broads, suggested an idea on which he had been working for many years to the British Government and industrial circles. It was the idea of supporting a craft on a 'pad', or cushion, of low-pressure air, ringed with a curtain of higher pressure air. Ever since, people have had difficulty in deciding whether the craft should be ranged among ships, planes, or land vehicles -- for it is something in between a boat and an aircraft. As a shipbuilder, Cockerell was trying to find a solution to the problem of the wave resistance which wastes a good deal of a surface ship's power and limits its speed. His answer was to lift the vessel out of the water by a great number of ring-shaped air jets on the bottom of the craft. It 'flies', therefore, but it cannot fly higher -- its action depends on the surface, water or ground, over which it rides.
The first tests on the Solent in 1959 caused a sensation. The hovercraft travelled first over the water, then mounted the beach, climbed up the dunes, and sat down on a road. Later it crossed the Channel, riding smoothly over the waves, which presented no problem.
Since that time, various types of hovercraft have appeared and taken up regular service. The hovercraft is particularly useful in large areas with poor communications such as Africa or Australia; it can become a 'flying fruit-bowl', carrying bananas from the plantations to the ports; giant hovercraft liners could span the Atlantic; and the railway of the future may well be the 'hovertrain', riding on its air cushion over a single rail, which it never touches, at speeds up to 300 m.p.h. -- the possibilities appear unlimited.
EGON LARSEN The Pegasus Book of Inventors
New words and expressions 生词和短语
hovercraft
n. 气垫船
n. 诺福克郡的湖泊地区
cushion
n. 座垫
ring
v. 围
Solent
n. （英国的）苏伦特海峡
sensation
n. 轰动
dune
n. 沙丘
plantation
n. 种植园
hovertrain
n. 气垫火车
本世纪已研制出许多新奇的交通工具，其中最新奇的要数气垫船了。1953年，有一位50多岁名叫克里斯托弗.科克雷的原电子工程师，改行在诺福克郡的湖泊地区从事造船业，他向英国政府和工业界提出了他研究多年的一项计划。他的设想是：用一个低压空气或软垫来支撑船体，软垫周围用高压空气环绕。自那以后，人们很难决定是否应该将这种运载工具列为轮船、飞机，或是陆上交通工具，因为它是介于船和飞机之间。作为一个船舶技师，科克雷尔在寻找解决波浪阻力的方法，因为波浪阻力浪费掉了船在水面行驶的大量动力，从而限制了船的速度。他的解决办法是把船体提离水面，让船在一个气垫上行驶，气垫只有一两英尺厚。船底装上大量环状喷气嘴以实现这一目的。这样，船就能飞了，但飞不高。它的飞行限决于它所悬浮的水面或地面。
1959年，在苏伦特海峡进行的首次试航引起了轰动，气垫船先是在水面上行驶，后又登上海岸，爬上沙丘，最后停在路上。后来气垫船跨越英吉利海峡，平衡地在波浪上方行驶，波浪不再产生阻力。
从那以后，各种各样的气垫船出现了，并开始了定期航行服务。气垫船在非洲、澳大利亚等交通不发达地区特别有用。它能成为“飞行水果盘子”，把香蕉从种植园动到港口。大型的气垫班轮或许能跨越大西洋。未来的火车或许能成为“气垫火车”，靠气垫在单轨上行驶而不接触轨道，时速可达每小时300英里。气垫船的前途是不可限量的。
Lesson 30
Exploring the sea-floor
海底勘探
First listen and then answer the following question.
How did people probably imagine the sea-floor before it was investigated?
Our knowledge of the oceans a hundred years ago was confined to the two-dimensional shape of the sea surface and the hazards of navigation presented by the irregularities in depth of the shallow water close to the land. The open sea was deep and mysterious, and anyone who gave more than a passing thought to the bottom confines of the oceans probably assumed that the sea bad was flat. Sir James Clark Ross had obtained a sounding of over 2,400 fathoms in 1839, but it was not until of deep soundings was obtained in the Atlantic and the first samples were collected by dredging the bottom. Shortly after this the famous H. M. S. Challenger expedition established the study of the sea-floor as a subject worthy of the most qualified physicists and geologists. A burst of activity associated with the laying of submarine cables soon confirmed the challenger's observation that many parts of the ocean were two to there miles deep, and the existence of underwater features of considerable magnitude.
Today, enough soundings are available to enable a relief map of the Atlantic to be drawn and we know something of the great variety of the sea bed's topography. Since the sea covers the greater part of the earth's surface, it is quite reasonable to regard the sea floor as the basic form of the crust of the earth, with, superimposed upon, it the continents, together with the islands and other features of the oceans. The continents form rugged tablelands which stand nearly three miles above the floor of the open ocean. From the shore line, out a distance which may be anywhere from a few miles to a few hundred miles, runs the gentle slope of the continental shelf, geologically part of the continents. The real dividing line between continents and oceans occurs at the foot a steeper slope.
This continental slope usually starts at a place somewhere near the 100-fatheom mark and in the course of a few hundred miles reaches the true ocean floor at 2,500-3,500 fathoms. The slope averages about 1 in 30. but contains steep, probably vertical, cliffs, and gentle sediment-covered terraces, and near its lower reaches there is a long tailing-off which is almost certainly the result of material transported out to deep water after being eroded from the continental masses.
T.F.GASKELL Exploring the Sea-floor from Science Survey
New words and expressions 生词和短语
n. 航海
sounding
n. 水深度
fathom
n. 寻（1寻等于1.8米）
porcupine
n. 箭猪
dredge
v. 挖掘
expedition
n. 远征
physicist
n. 物理学家
magnitude
n. 很多
topography
n. 地形
crust
n. 地壳
rugged
tableland
n. 高地
sediment
n. 沉淀物
terrace
n. 阶地
erode
v. 侵蚀
100年前，我们只知道海洋是二维平面形的，以及靠近陆地浅水区的深浅不一能给航行带来危险。无边无际的海洋深邃而又神秘，凡是稍稍想过大海海底的人大概都会认为海底是平坦的。1839年，詹姆斯.克拉克.罗斯爵士曾测得海水深度超过2，400英寻；但直到1869年，皇家学会用英国“豪猪”号舰艇进行了几次巡航后，才在大西洋测得一个海水深度，同时能过挖掘海底，取得了研究海底的首批样品。此后不久，英国著名的“挑战者”号舰艇对海底的那次考察，把对海床的研究确立为一个值得一流物理学家和地质学家从事的研究课题，铺设海底电缆的热潮很快证实了“挑战者”号的观察结果：海洋中很多地方可深达两三英里，水下特征差异极大。
现在已有足够的水深测量数据来绘制一张大西洋洋底地形图，而且我对海底地形的千变万化也有了一定的了解。既然海洋覆盖着地球的大部分表面，因此完全有理由把海床看作地壳的基本模壳，上面附加着大陆以及岛屿和海洋的其他形态。大陆是崎岖不平的高地，高出辽阔的海洋海底近三英里。从海岸线向大海延伸几英里到几百英里的区域是大陆架慢坡，从地质学上来说，它是大陆的一部分。大陆和海洋的真正分界线是在陡破脚下。
大陆架慢坡一般是从差不多100英寻水深的地方开始的，一直延伸到几百英里远深达2，500至3，500的地方，那里才是真正的海底。坡度平均约为1/30，但其中包括陡峭的、乃至垂直的峭壁和沉积物覆盖的缓和的阶梯地带，在这个地带的低处是很长的一段尾沙地段，基本上可以断定这个地段是大陆块体上侵蚀下来的物质被水冲到深水处形成的。
Lesson 31
The sculptor speaks
雕塑家的语言
First listen and then answer the following question.
What do you have to be able to do to appreciate sculpture?
Appreciation of sculpture depends upon the ability to respond to form in there dimension. That is perhaps why sculpture has been described as the most difficult of all arts; certainly it is more difficult than the arts which involve appreciation of flat forms, shape in only two dimensions. Many more people are 'form-blind' than colour-blind. The child learning to see, first distinguishes only two-dimensional shape; it cannot judge distances, depths. Later, for its personal safety and practical needs, it has to develop (partly by means of touch) the ability to judge roughly three-dimensonal distances. But having satisfied the requirements of practical necessity, most people go no further. Though they may attain considerable accuracy in the perception of flat from, they do no make the further. Though they may attain considerable accuracy in the perception of flat form, they do not make the further intellectual and emotional effort needed to comprehend form in its full spatial existence.
This is what the sculptor must do. He must strive continually to think of, and use, form in its full spatial completeness. He gets the solid shape, as it were, inside his head-he thinks of it, whatever its size, as if he were holding it completely enclosed in the hollow of his hand. He mentally visualizes a complex form from all round itself; he knows while he looks at one side what the other side is like, he identifies himself with its centre of gravity, its mass, its weight; he realizes its volume, as the space that the shape displaces in the air.
And the sensitive observer of sculpture must also learn to feel shape simply as shape, not as description or reminiscence. He must, for example, perceive an egg as a simple single solid shape, quite apart from its significance as food, or from the literary idea that it will become a bird. And so with solids such as a shell, a nut, a plum, a pear, a tadpole, a mushroom, a mountain peak, a kidney, a carrot, a tree-trunk, a bird, a bud, a lark, a ladybird, a bulrush, a bone. From these he can go on to appreciate more complex forms of combinations of several forms.
HENRY MOORE The Sculptor Speaks from The Listener
New words and expressions 生词和短语
colour-blind
perception
n. 知觉
comprehend
v. 理解
spatial
visualize
v. 使具形象，设想
reminiscence
n. 回忆，联想
n. 蝌蚪
mushroom
n. 蘑菇
carrot
n. 胡萝卜
bud
n. 花蕾
lark
n. 云雀
n. 瓢虫
bulrush
n. 芦苇
对雕塑的鉴赏力取决于对立体的反应能力。雕塑被说成是所有艺术中最难的艺术，可能就是这个道理。欣赏雕塑品当然比欣赏平面的艺术品要难。“形盲”的人数比“色盲”的人数要多得多。正在学看东西的儿童起初只会分辨二维形态，不会判断距离和深度。慢慢地，由于自身安全和实际需要，儿童必须发展（部分通过触觉）粗略判断三维空间距离的能力。但是。大部分人在满足了实际需要后，就不再继续发展这种能力了。虽然他们对平面形的感觉能达到相当准确的程度，但他们没有在智力和感情上进一步努力去理解存在于空间的整个形态。
而雕塑家就必须做到这一点。他必须勤于想像并且利用形体在空间中的完整性。可以说，当他想像一个物体时，不管其大小如何，他脑子里得到的是一个立体的概念，就好像完全握在自己手心里一样。他的大脑能从物体周围的各个角度勾画出其复杂的形象，他看物体的一边时，便知道另一边是个什么样子。他把自身和物体重心、质量、重量融为一体。他能意识到物体的体积，那就是它的形状有空气中所占的空间。
因此，敏锐的雕塑观赏者也必须学会把形体作为形体来感觉，不要靠描述和印象去想象。以鸟蛋为例。观赏者必须感觉到它是一个单一的实体形态，而完全不靠它的食用意义或它会变成鸟这样的文字概念来感觉。对于其他实体，如，贝壳、核桃、李子、梨子、蝌蚪、蘑菇、山峰、肾脏、胡萝卜、树干、鸟儿、花蕾、云雀、瓢虫、芦苇以及骨头也应这样来感觉。从这些形体出发，观赏者可进一步观察更为复杂的形体或若干形体的组合。
Lesson 32
Galileo reborn
伽利略的复生
First listen and then answer the following question.
What has modified out traditional view of Galileo in recent times?
In his own lifetime Galileo was the centre of violent controversy; but the scientific dust has long since settled, and today we can see even his famous clash with the Inquisition in something like its proper perspective. But, in contrast, it is only in modern times that Galileo has become a problem child for historians of science.
The old view of Galileo was delightfully uncomplicated. He was, above all, a man who experimented: who despised the prejudices and book learning of the Aristotelians, who put his questions to nature instead of to the ancients, and who drew his conclusions fearlessly. He had been the first to turn a telescope to the sky, and he had seen there evidence enough to overthrow Aristotle and Ptolemy together. He was the man who climbed the Leaning Tower of Pisa and dropped various weights from the top, who rolled balls down inclined planes, and then generalized the results of his many experiments into the famous law of free fall.
But a closer study of the evidence, supported by a deeper sense of the period, and particularly by a new consciousness of the philosophical undercurrents in the scientific revolution, has profoundly modified this view of Galileo. Today, although the old Galileo lives on in many popular writings, among historians of science a new and more sophisticated picture has emerged. At the same time our sympathy fro Galileo's opponents ahs grown somewhat. His telescopic observations are justly immortal; they aroused great interest at the time, they had important theoretical consequences, and they provided a striking demonstration of the potentialities hidden in instruments and apparatus. But can we blame those who looked and failed to see what Galileo saw, if we remember that to use a telescope at the limit of its powers calls for long experience and intimate familiarity with one's instrument? Was the philosopher who refused to look through Galileo's telescope more culpable than those who alleged that the spiral nebulae observed with Lord Rosse's great telescope in the eighteen-forties were scratches left by the grinder? We can perhaps forgive those who said the moons of Jupiter were produced by Galileo's spyglass if we recall that in his day, as for centuries before, curved glass was the popular contrivance for producing not truth but illusion, untruth; and if a single curved glass would distort nature, how much more would a pair of them?
MICHAEL HOSKIN Galileo Reborn from The Listener
New words and expressions 生词和短语
controversy
n. 争议，争论
dust
n. 纠纷，骚动
clash
n. 冲突
Inquisition
n. （罗马天主教的）宗教法庭
perspective
n. 观点，看法
despise
v. 蔑视
generalize
v. 归纳
undercurrent
n. 潜流
theoretical
potentiality
n. 潜能
intimate
familiarity
n. 熟悉的
culpable
Aristotelian
n. 亚里士多德学派的人
Aristotle
n. 亚里士多德（公元前384-322，古希腊哲学家）
Ptolemy
n. 托勒密（公元90-168，古希腊天文学家）
Leaning Tower of Pisa
比萨斜塔
spiral
nebula
n. 星云
scratch
n. 擦痕
contrivance
n. 器械
distort
v. 歪曲
伽利略在世时是激烈论战的中心。但是，自他逝世以来，那场科学上的纷争早已平息了下来，甚至他和宗教法庭的著名冲突，我们今天也能正确如实地看待。但是相比之下，对于科学史家来说，伽利略只是在现代才变成了一个新的难题。
令人高兴的是，过去对伽利略的看法并不复杂。他首先是个实验工作者，他蔑视亚里士多德学派的偏见和空洞的书本知识。他向自然界而不是向古人提出问题，并大胆地得出结论。他是第一个把望远镜对准天空的人，观察到的论据足以把亚里士多德和托勒密一起推翻。他就是那个曾经爬上比萨斜塔，从塔顶向下抛掷积各种重物的人；他是那个使地球体沿斜面向下滚动，然后将多次实验结果概括成著名的自由落体定律的人。
但是，对那个时代的深化了解，尤其是以科学家革命中哲学潜流的新意识为依据，进一步仔细研究，就会极大地改变对伽利略的看法。今天，虽然已故的伽利略继续活在许多通俗读物中，但在科学史家中间，一个新的更加复杂的伽利略形象出现了。与此同时，我们对伽利略的反对派的同情也有所增加。伽利略用望远镜所作的观察确实是不朽的，这些观察当时引起人们极大的兴趣，具有重要的理论意义，并充分显示出了仪表和仪器的潜在力量。但是，如果我们想到，便用一架倍数有限的望远镜需要长期的经验和对自己仪器的熟悉程度，那么我们怎么能去责备观察了天空但没有看到伽利略所看到的东西的那些人呢？某位哲学家曾拒绝使用伽利略的望远镜去观察天空；到了19世纪40年代，有人硬把罗斯勋爵高倍望远镜观测到的螺旋状星云说成是磨镜工留下的磨痕。难道反对伽利略的哲学家比诋毁罗斯勋爵造谣者应受到更大的谴责吗？如果我们回想一下伽利略之前几个世纪期间，曲面镜一直是一种用于产生幻影而不是产生真象的把戏装置，那么我们就会原谅那些当时把伽利略观察到的木星卫生说成是伽利略用他的小望远镜变出来的人们，何况一片曲面镜就可歪曲自然，那么伽利略的两片曲面镜对自然的歪曲又该多大呢？
Lesson 33
Education
教育
First listen and then answer the following question.
Why is education democratic in bookless, tribal societies?
Education is one of the key words of our time. A man without an education, many of us believe, is an unfortunate victim of adverse circumstances, deprived of one of the greatest twentieth-century opportunities. Convinced of the importance of education, modern states 'invest' in institutions of learning to get back 'interest' in the form of a large group of enlightened young men and women who are potential leaders. Education, with its cycles of instruction so carefully worked out, punctuated by textbooks -- those purchasable wells of wisdom-what would civilization be like without its benefits?
So much is certain: that we would have doctors and preachers, lawyers and defendants, marriages and births -- but our spiritual outlook would be different. We would lay less stress on 'facts and figures' and more on a good memory, on applied psychology, and on the capacity of a man to get along with his fellow-citizens. If our educational system were fashioned after its bookless past we would have the most democratic form of 'college' imaginable. Among tribal people all knowledge inherited by tradition is shared by all; it is taught to every member of the tribe so that in this respect everybody is equally equipped for life.
It is the ideal condition of the 'equal start' which only our most progressive forms of modern education try to regain. In primitive cultures the obligation to seek and to receive the traditional instruction is binding to all. There are no 'illiterates' -- if the term can be applied to peoples without a script -- while our own compulsory school attendance became law in Germany in 1642, in France in 1806, and in England in 1876, and is still non-existent in a number of 'civilized' nations. This shows how long it was before we deemed it necessary to make sure that all our children could share in the knowledge accumulated by the 'happy few' during the past centuries.
Education in the wilderness is not a matter of monetary means. All are entitled to an equal start. There is none of the hurry which, in our society, often hampers the full development of a growing personality. There, a child grows up under the ever-present attention of his parent; therefore the jungles and the savannahs know of no 'juvenile delinquency'. No necessity of making a living away from home results in neglect of children, and no father is confronted with his inability to 'buy' an education for his child.
JULIUS E. LIPS The Origin of Things
New words and expressions 生词和短语
purchasable
preacher
n. 传教士
defendant
n. 被告
outlook
n. 视野
capacity
n. 能力
democratic
tribal
n. 部落的
tribe
n. 部落
illiterate
n. 文盲
compulsory
deem
v. 认为
means
n. 方法，手段，财产，资力
hamper
v. 妨碍
savannah
n. 大草原
juvenile
delinquency
n. 犯罪
教育是我们这个时代的关键词之一。我们许多人都相信，一个没有受过教育的人，是逆境的牺牲品，被剥夺了20世纪的最优越的机会之一。现代国家深深懂得教育的重要性，对教育机构投资，收回的‘利息’便是培养出大批有知识的男女青年，这些人可能成为未来的栋梁。教育，以其教学周期如此精心地安排，并以教科书 -- 那些可以买到的智慧源泉 -- 予以强化，如果不受其惠，文明将会是个什么样子呢？
至少，这些是可以肯定的：虽然我们还会有医生和牧师、律师和被告、婚姻和生育，但人们的精神面貌将是另一个样子。人们不会重视‘资料和数据’，而靠好记性、实用心理学与同伴相处的能力。如果我们的教育制度仿效没有书籍的古代教育，我们的学院将具有可以想象得出的最民主的形式了。在部落中，通过传统继承的知识为所有人共享，并传授给部落中的每一个成员。从这个意义上讲，人人受到的有关生活本领的教育是相等的。
这就是我们最进步的现代教育试图恢复的“平等起步”的理想状况。在原始文化中，寻求和接受传统教育的义务对全民都有约束力。因而没有“文盲”（如果这个字眼儿可以用于没有文字的民族的话）。而我们的义务教育成为法律在德国是在1642年，在法国是在1806年，在英国是在1876年。今天，在许多“文明”国家里，义务教育迄今尚未实行。这说明，经过了多么漫长的时间之后，我们才认识到，有必要确保我们的孩子享有多少个世纪以来由‘少数幸运者’所积累起来的知识。
荒凉地区的教育不是钱的问题，所有的人都享有平等起步的权利。那里没有我们今天社会中的匆忙生活，而匆忙的生活常常妨碍个性的全面发展。荒凉地区的孩子无时无刻不在父母关怀下成长。因此，丛林和荒凉地区不知道什么叫“青少年犯罪”。人们没有必要离家谋生，所以不会产生孩子无人管的问题，也不存在父亲无力为孩子支付教育费用而犯难的问题。
Lesson 34
青春期
First listen and then answer the following question.
What do adolescents respect in parents?
Parents are often upset when their children praise the homes of their friends and regard it as a slur on their own cooking, or cleaning, or furniture, and often are foolish enough to let the adolescents see that they are annoyed. They may even accuse them of disloyalty, or make some spiteful remark about the friends' parents. Such loss of dignity and descent into childish behaviour on the part to their parents about the place or people they visit. Before very long the parents will be complaining that the child is so secretive and never tells them anything, but they seldom realize that they have brought this on themselves.
Disillusionment with the parents, however good and adequate they may be both as parents and as individuals, is to some degree inevitable. Most children have such a high ideal of their parents, unless the parents themselves have been unsatisfactory, that it can hardly hope to stand up to a realistic evaluation. Parents would be greatly surprised and deeply touched if they hope to stand up to a realistic evaluation. Parents would be greatly surprised and deeply touched if they realized how much belief their children usually have in their character and infallibility, and how much this faith means to a child. If parents were prepared for this adolescent reaction, and realized that it was a sign that the child was growing up and developing valuable powers of observation and independent judgment, they would not be so hurt, and therefore would not drive the child into opposition by resenting and resisting it.
The adolescent, with his passion for sincerity, always respects a parent who admits that he is wrong, or ignorant, or even that he has been unfair or unjust. What the child cannot forgive is the parent's refusal to admit these charges if the child knows them to be true.
Victorian parents believed that they kept their dignity by retreating behind an unreasoning authoritarian attitude; in fact they did nothing of the kind, but children were then too cowed to let them know how they really felt. Today we tend to go to the other extreme, but on the whole this is a healthier attitude both for the child and the parent. It is always wiser and safer to face up to reality, however painful it may be at the moment.
DOTID OFLUM Journey Through Adolescence
New words and expressions 生词和短语
n.
slur
n. 青春期
n. 底毁
disloyalty
n. 青少年（12-18岁）
spiteful
disillusionment
n. 幻灭感
evaluation
n. 评价
infallibility
n. 一贯正确
resent
v. 怨恨
sincerity
n. 诚挚
victorian
retreat
v. 后退
unreasoning
authoritarian
cow
v. 吓唬
当家长听到孩子赞扬自己朋友的家时，总感到不安，认为孩子在嫌弃自家的饭菜、卫生、或家具，而且愚蠢地让孩子看出自己的烦恼。他们甚至责备孩子不忠，或者讲些小朋友家长的坏话。家长这种有失身份和孩子气的作法使青春期的孩子大为震惊，决心以后不再向父母讲述去过的地方和见过的人。不要很久,家长就会抱怨孩子守口如瓶，什么事也不告诉他们，殊不知这是他们自找的。
不管家长的人品有多么好，作为父母有多么合格，孩子们对家长幻想的破灭在某种程度上是不可避免的。除非父母自身不能令人满意，大多数孩子对父母估价过高，以致这种估价很难指望经受住现实的考验。如果家长意识到孩子们通常是多么相信家长的品行和绝对正确，意识到孩子们的这种信念会对孩子产生多么大的影响，那么家长会大为吃惊和深受感动的。如果家长对青少年的这种反应有思想准备，并且意识到这象征着孩子们正在成熟和正在发展宝贵的观察力、独立判断力，那么他们就不会那样伤心，也就不会由于怨恨和抵触这种反应，而把孩子推到自己的对立面去。
青少年酷爱真诚，对于能够承认错误或无知、甚至承认自己做得不分平或不公正的父母，他们总是尊敬的，孩子们所不能原谅的是：父母错了，孩子们也看出来了，可是做父母的还不肯承认。
维多利亚时代的父母认为，他们可靠无理的权威气派来维护自己的尊严，实际上那是根本不行的。孩子们只不过被吓得不敢让父母知道自己的想法罢了。虽然现在我们倾向于走向另一个极端，但总地来看，孩子和家长双方态度都比较端正。遇事采取面对现实的态度总是比较明智和稳妥的，尽管会有暂时的痛苦。
Lesson 35
Space odyssey
太空探索
First listen and then answer the following question.
When will it be possible for us to think seriously about colonising Mars?
The Moon is likely to become the industrial hub of the Solar System, supplying the rocket fuels fro its ships, easily obtainable from the lunar rocks in the from of liquid oxygen. The reason lies in its gravity. Because the Moon has only an eightieth of the Earth's mass, it requires 97 per cent less energy to travel the quarter of a million miles from the Moon to Earth-orbit than the 200 mile-journey from Earth's surface into orbit!
This may sound fantastic, but it is easily calculated. To escape from the Earth in a rocket, one must travel at seven miles per second. The comparable speed from the Moon is only 1.5 miles per second. Because the gravity on the Moon's surface is only a sixth of Earth's (remember how easily the Apollo astronauts bounded along), it takes much less energy to accelerate to that 1.5 miles per second than it does on Earth. Moon-dwellers will be able to fly in space at only three per cent of the cost of similar journeys by their terrestrial dwellers will be able to fly in space at only three per cent of the cost of similar journeys by their terrestrial cousins.
Arthur C. Clark once suggested a revolutionary idea passes through three phases:
1 'It's impossible -- don't waste my time.'
2 'It's possible, but not worth doing.'
3 'I said it was a good idea all along.'
The idea of colonising Mars -- a world 160 times more distant time the Moon -- will move decisively from the second phase to the third, when a significant number of people are living permanently in space. Mars has an extraordinary fascination for would-be voyagers. America, Russia and Europe are filled with enthusiasts -- many of them serious and senior scientists -- who dream of sending people to it. Their aim is understandable. It is the one world in the Solar System that is most like the Earth. It is a world of red sandy deserts (hence its name -- the Red Planet), cloudless skies, savage sandstorms, chasms wider than the Grand Canyon and at least one mountain more than twice as tall as Everest. It seems ideal for settlement.
7 DAYS, February 19, 1989
New words and expressions 生词和短语
hub
n. （活动的）中心
lunar
oxygen
n. 氧气
Apollo
n. 阿波罗
accelerate
v. 加速
terrestrial
permanently
fascination
n. 魅力
senior
chasm
n. 断层，裂口
canyon
n. 峡谷
月球很可能成为太阳系的工业中心。从月球上的岩石中很容易提炼出液态氧，作为航天飞船的燃料。其原因在于月球的重力。因为月球的重只有地球的1/8，因此，从月球到地球的25万英里所消耗的能量要比从地球表面进入地球轨道的200英里所耗能量少97%。
这点听起来令人难以置信，但却很容易计算出来。要乘坐一枚火箭飞离地球，火箭的速度要达到每秒7英里，而从月球出发的相应速度史是每秒1.5英里。由于月球表面的重力仅是地球表面的1/6 -- 还记得阿波罗飞船中的宇航员累松地跳跃 -- 在月球上加速到每秒1.5英里比在地球上所用能源要少得多。月球居民在太空遨游的费用仅是地球上朋友飞越同样路所需费用的3%。
亚瑟.C.克拉克曾提议，一种创新的想法要经过以下3个阶段：
1 “根本不可能，不要浪费我的时间。”
2 “可能，但不值得做。”
3 “我一直说这是个好想法。”
如果有相当数量的人永久性地住在太空，征服火星的计划 -- 一个比月球远160倍的星球 -- 就可以明确地从第2阶段进入第3阶段。火星对未来的星际旅客说有着特殊的魅力。美国、俄罗斯和欧洲都有许多热心此项事业的人 -- 其中的不少是认真和资深的科学家，他们一直梦想着把人送上火星。他们的目标是可以理解的。火星是太阳系里与地球最接近的一颗行星。这是一个红色沙漠的世界（因而得名：红色行星），无云的天空，凶猛的沙暴，比大峡谷还宽的裂缝，起码有一座山有珠穆朗玛峰的近两倍高。看起来，它很合适居住。
Lesson 36
The cost of government
政府的开支
First listen and then answer the following question.
What is the most important factor, both in government or business, for keeping running costs low?
If a nation is essentially disunited, it is left to the government to hold it together. This increases the expense of government, and reduces correspondingly the amount of economic resources that could be used for developing the country. And it should not be forgotten how small those resources are in a poor and backward country. Where the cost of government is high, resources for development are correspondingly low.
It is precisely the same with a nation. To the extent that the people can be relied upon to behave in a loyal and responsible manner, the government does not require armies of police and civil servants to keep them in order. But if a nation is disunited, the government cannot be sure that the actions of the people will be in the interests of the nation; and it will have to watch, check, and control the people accordingly. A disunited nation therefore has to incur unduly high costs of government.
RAYMOND FROST The Backward Society
New words and expressions 生词和短语
disunited
correspondingly
backward
incur
v. 承担
v. 管理
analogous
n. 一般费用
initiative
n. 主动，积极性
checker
n. 检查人员
foreman
n. 监工
dividend
n. 红利
unduly
如果一个国家实际上处于分裂状态，使之联合起来就是政府的事了。这样的一来就增加了政府的开支，从而相应地减少了可以用来了展国家的那部分经济资源。不应忘记，在一个贫穷落后的国家里，那部分财力是很有限的。凡是政府管理费用高的地方，用于发展国家经济的资金就会相应地减少。
把国家的状况同私人企业的状况加以比较，就可以看清这个问题。一个企业为了继续经营，不得不支出一定的费用和开销。就我们的目的而言，我们只关心一种费用 -- 企业行政管理费。一家企业的行政管理开支类似于一个国家的政府管理所用的开支。如果企业中的每个人都在真诚地为提高企业利润而工作，那么企业的管理费用就会降低到相应的程度。如果企业的每个人都信得过，人人都认真负责，在各自的工作范围内发挥主动性，行政管理费用就会降低。行政管理费用的降低的原因是：每项工作只需要一个人去完成，用不着另外再有一个人检查工作。督促他遵守章程，或向有关人士汇报他的工作。但是，如果企业中谁也不可信赖会对工作尽忠守职，那公企业就会需大批的管理人员、检查人员和带班人员，管理费用就会相应在增加。管理费用增加了，那么在扣除管理费用后，企业的收入就降低了。因此用于分红的金额就用于将来开拓和发展的投资就相应地减少了。
一个国家的情况也完全相同。如果人民忠于职守，举止规矩，能受到政府的信赖，那么政府就不需要大批的警察和文职人员运去促使人民遵纪守法。但是，如果一个国家处于分裂状态，政府不能相信人民的行动有利于国家，那么政府就不得不对人民进行监督、检查和控制。因此，一个处于分裂的国家必须要支付过高的行政管理费用。
Lesson 37
The process of ageing
衰老过程
First listen and then answer the following question.
What is one of the most unpleasant discoveries we make about ourselves as we get older?
At the age of twelve years, the human body is at its most vigorous. It has yet to reach its full size and strength, and its owner his or her full intelligence; but at this age the likelihood of death is least. Earlier, we were infants and young children, and consequently more vulnerable; later, we shall undergo a progressive loss of our vigour and resistance which, though imperceptible at first, will finally become so steep that we can live no longer, however well we look after ourselves, and however well society, and our doctors, look after us. This decline in vigour with the passing of time is called ageing. It is one of the most unpleasant discoveries which we all make that we must decline in this way, that if we escape wars, accidents and disease we shall eventually 'die of old age', and that this happens at a rate which differs little from person to person, so that there are heavy odds in favour of our dying between the ages of sixty-five and eighty. Some of us will die sooner, a few will live longer -- on into a ninth or tenth decade. But the chances are against it, and there is a virtual limit on how long we can hope to remain alive, however lucky and robust we are.
Normal people tend to forget this process unless and until they are reminded of it. We are so familiar with the fact that man ages, that people have for years assumed that the process of losing vigour with time, of becoming more likely to die the older we get, was something self-evident, like the cooling of a hot kettle or the wearing-out of a pair of shoes. They have also assumed that all animals, and probably other organisms such as trees, or even the universe itself, must in the nature of things 'wear out'. Most animals we commonly observe do in fact age as we do, if given the chance to live long enough; and mechanical systems like a wound watch, or the sun, do in fact run out of energy in accordance with the second law of thermodynamics (whether the whole universe does so is a moot point at present). But these are not analogous to what happens when man ages. A run-down watch is still a watch and can be rewound. An old watch, by contrast, becomes so worn and unreliable that it eventually is not worth mending. But a watch could never repair itself -- it does not consist of living parts, only of metal, which wears away by friction. We could, at one time, repair ourselves --well enough, at least, to overcome all but the most instantly fatal illnesses and accidents. Between twelve and eighty years we gradually lose this power; an illness which at twelve would knock us over, at eighty can knock us out, and another 700 for the survivors to be reduced by half again.
ALEX COMFORT The process of ageing
New words and expressions 生词和短语
likelihood
n. 可能性
infant
n. 婴儿
vulnerable
imperceptible
steep
ageing
n. 老化
odds
n. 可能性
virtual
robust
organism
n. 有机体
thermodynamics
n. 热力学
moot
run-down
friction
n. 摩擦
人体在12岁时是生命力最旺盛的时期。虽然这个时期人的身材、体力和智力还有待发展和完善，但在这个年龄死亡的可能性最小。再早一些，我们是幼儿和小孩子，身体较脆弱；再迟一些，我们就要经历生命力和抵抗力逐步衰退的过程。虽然这个过程起初难以觉察，但最终会急转直下，不管我们怎样精心照料我们自己，不管社会和医生怎样对我们进行精心照顾，我们也无法再活下去了。生命力随着时间的流失而衰退叫做衰老。人类发现的最不愉快的一个事实是：人必然会衰老。既使我们能避开战争、意外的事故和各种疾病，我们最终也会“老死”；衰老的速度在人与人之间相差甚微，我们最可能死亡的年龄在65至80岁之间，有些人会死得早一些，少数人寿命会长一些 -- 活到八十几岁或九十几岁，但这种可能性很小。不管我们多么幸运，多么健壮，我们所希望的长寿实际上是有限度的。
衰老的过程，不经提起，正常人容易忘记；一经提醒，才会记起。我们对人总是要衰老的现象并不陌生，多年来就已认识到。生命随着时间流失而丧失活力，人随着年龄的增长而接近死亡，这是不言而喻的，就像一壶热水迟早会凉不来，一双鞋渐渐会磨破一样。人们不但认识到所有的动物，大概也认识到所有的有机物。如树木，甚至宇宙本身，从事物的本质上来说都会“磨损掉”。我们通常看到的大多数动物，即使能让它们活得足够长久的话，也会像我们一样衰老的。像上紧发条的手表那样的机械装置，或太阳，也都会消耗完其能量（整个宇宙否如此，目前沿有争论）。不过，这些衰老的情况同人并不相似。手表停了依然是只手表，还可以重上好发条。然而一只老掉牙的手表，磨损太厉害，老得一点儿不准了，最终不值得修理了。但是，手表决不会自行修理，它不是由有生命的部件组成，而是由金属组成，而金属可以随着磨擦而磨损殆尽。而我们人，在一定时间内是可以自行修复的，除了暴病死或意外事故外，至少足以克服一切疾病和事故。在12岁至80岁之间，我们逐渐丧失这种能力。能使我们在12岁时病倒的疾病，到了80岁可能会使我们一厥不振而进入坟墓。假如我们能保持12岁时的旺盛生命力，那么我们当中的一半人过700年才会死去，剩下的一半人再过700年，才会又减少一半。
Lesson 38
Water and the traveller
水和旅行者
First listen and then answer the following question.
What does this text describe?
Contamination of water supplies is usually due to poor sanitation close to water sources, sewage disposal into the sources themselves, leakage of sewage into distribution systems or contamination with industrial or farm waste. Even if a piped water supply is safe at its source, it is not always safe by the time it reaches the tap. Intermittent tap-water supplies should be regarded as particularly suspect.
Travellers on short trips to areas with water supplies of uncertain quality should avoid drinking tap-water, or untreated water from any other source. It is best to hot drinks, bottled or canned drinks of well-known brand names -- international standards of water treatment are usually followed at bottling plants. Carbonated drinks are acidic, and slightly safer. Make sure that all bottles are opened in your presence, and that their rims are clean and dry.
Boiling is always a good way of treating water. Some hotels supply boiled water on request and this can be used for drinking, or for brushing teeth. Portable boiling elements that can boil small quantities of water are useful when the right voltage of electricity is available. Refuse politely any cold drink from an unknown source.
Ice is only as safe as the water from which it is made, and should not be put in drinks unless it is known to be safe. Drink can be cooled by placing them on ice tather than adding ice to them.
Alcohol may be a medical disinfectant, but should not be relied upon to sterilize water. Ethanol is more effective at a concentration of 50-70 per cent; below 20 per cent, its bactericidal action is negligible. Spirits labelled 95 proof contain only about 47 per cent alcohol. Beware of methylated alcohol, which is very poisonous, and should never be added to drinking water.
If no other safe supply can be obtained, tap water that is too hot to touch can be left to cool and is generally safe to drink. Those planning a trip to remote areas, or intending to live in countries where drinking water is not readily available, should know about the various possible methods for making water safe.
RICHARD DAWOOD Travellers' Health
New words and expressions 生词和短语
contamination
n. 污染
sanitation
n. 卫生，卫生设备
sewage
n. 污水
leakage
n. 泄漏
intermittent
carbonated
acidic
alcohol
n. 酒精
disinfectant
n. 消毒剂
sterilize
v. 消毒
ethanol
n. 乙醇
bactericidal
negligible
methylated
水源的污染通常是由于接近水源的地方卫条件太差而造成的：污水排入水源，污水渗入给水系统或工农业污水造成污染。即使管道供水系统在水源处安全的，等水到达龙头时就不一定总是安全的了。断断续续的水管应该被视为是非常可疑的。
短途旅行到水质不保险的地区时，应避免饮用水龙头的水或未经处理任何其他来源的水。最好仅饮用开水，名牌瓶装或罐装水 -- 装瓶厂通常遵循国际水处理的标准。碳酸饮料是酸性的，就更安全一些。确保瓶子是当你面开启的，瓶口清洁干燥。
烧开一直是水处理的一种好办法。有的酒店根据要求可提供开水，这些开水可用于饮用和刷牙。如果有相配的电压，可以煮少量水的便携式热水装置是有用的。应谢绝任何不明来源的冷饮。
冰块只有当制造冰块的水安全时才是保险的，只有知道冰块安全时才能加入饮料。可以把饮料置于冰块之上来冷却，而不是把冰块加进饮料之中。
酒精可能是医学上的消毒剂，但决不可用来消毒饮用水。乙醇的浓度为50%至70%时比较有效，浓度低于20%时，杀菌能力基本上就不存在了。强度标为95的酒中含有47%的酒精。要提防甲基化酒精，那是剧毒的，永远不能掺入饮用水。
如果没有其他安全的饮用水，水管中流出的烫手的水可以留下来冷却。这种水一般是安全的。那些计划去偏远地区旅行，或在饮用水不现成的国家居住的人，应该知道如何使水适于饮用的各种办法。
Lesson 39
What every writer wants
作家之所需
First listen and then answer the following question.
How do professional writers ignore what they were taught at school about writing?
I have known very few writers, but those I have known, and whom I respect, confess at once that they have little idea where they the are going when they first set pen to paper. They have a character, perhaps two; they are in that condition of eager discomfort which passes for inspiration; all admit radical changes of destination once the journey has begun; one, to my certain knowledge, spent nine months on a novel about Kashmir, then reset the whole thing in the Scottish Highlands. I never heard of anyone making a 'skeleton', as we were taught at school. In the breaking and remaking, in the timing, interweaving, beginning afresh, the writer comes to discern things in his material which were not consciously in his mind when he began. This organic process, often leading to moments of extraordinary self-discovery, is of an indescribable fascination. A blurred image appears; he adds a brushstroke and another, and it is gone; but something was there, and he will not rest till he has captured it. Sometimes the yeast within a writer outlives a book he has written. I have heard of writers who read nothing but their own books; like adolescents they stand before the mirror, and still cannot fathom the exact outline of the vision before them. For the same reason, writers talk interminably about their own books, winkling out hidden meanings, super-imposing new ones, begging response from those around them. Of course a writer doing this is misunderstood: he might as well try to explain a crime or a love affair. He is also, incidentally, an unforgivable bore.
This temptation to cover the distance between himself and the reader, to study his image in the sight of those who do not know him, can be his undoing: he has begun to write to please.
A young English writer made the pertinent observation a year or two back that the talent goes into the first draft, and the art into the drafts that follow. For this reason also the writer, like any other artist, has no resting place, no crowd or movement in which he may take comfort, no judgment from outside which can replace the judgment from within. A writer makes order out of the anarchy of his heart; he submits himself to a more ruthless discipline than any critic dreamed of, and when he flirts with fame, he is taking time off from living with himself, from the search for what his world contains at its inmost point.
JOHN LE CARRE What every writer wants from Harper's
New words and expressions 生词和短语
confess
v. 承认
inspiration
n. 灵感
Kashmir
n. 克什米尔
interweave
v. 交织
afresh
discern
v. 辨明，领悟
indescribable
blur
v. 使...模糊不清
yeast
n. 激动
fathom
v. 领悟，彻底了解
interminably
winkle
v. 挖掘
incidentally
pertinent
flirt
v. 调情
inmost
我的认识的作家寥寥无几，然而凡是我所认识和尊敬的作家，都立即承认在他们动笔时，不清楚要写什么，怎么写。他们心中只在一个或两个角色。他们处于急切不安的状态，而被当作是灵感。他们无不承认，一旦“旅程”开始，“目的地”常有急剧的变化。据我所知，有位作家花了9个月的时间写了一部关克什米尔的小说，后来却把整个故事背景换成了苏格兰高地。我从未听说过任何一位作家像我们在学校那样，动笔前先列什么提纲。作家在剪裁修改、构思时间、穿插情节、以至从头重写的过程中，会领悟到素材中很多东西是他刚动笔时所未意识到的。这种有机的加工过程往往达到不寻常自我发现的境界，具有难以言表的构思魅力。一个朦胧的形象出现在作家的脑海里，他左添一笔，右添一笔，形象反而消逝了；可是，好像还有什么东西存在着，不把它捕捉到，作家是不会罢休的。有时，一个作家一本书写完了，但兴奋仍不消散。我听说一些作家，除了自己的书外，别的书一概不读，犹如希腊神话中那位漂亮的少年，站在镜前，不能辨认自身的真面目。由于这个原因，作家喋喋不休地谈论自己的书，挖掘其隐晦的含义，询问周围人的反应。作家如此行事当然被人误解。他还不如给人讲一个犯罪案件或一个恋爱故事。顺便说一句，他也是个不可饶恕的令人厌烦的人。
这种企图消除自己和读者之间距离的作法，企图用不了解自己的人的观点来研究自己塑造的形象的作法，会导致作家的毁灭，因为他已经开始为取悦他人而写作了。
一两年前，一位年轻的英国作家发表了中肯的看法。他说，初稿是才华，以后各稿是艺术。也是由于这个原因，作家同任何艺术家一样，找不到可休息的场所，找不到伙伴和活动使自己得到安逸。任何局外人的判断也比不上他内心的正确判断。一旦作家从内心的紊乱中理出头绪，就应该按任何评论家想像不到的无情规范约束自己写作；当他沽名钓誉时，他就脱离了自我生活，脱离了对自己灵魂最深处世界的探索。
Lesson 39
Waves
海浪
First listen and then answer the following question.
What false impression does an ocean were convey to the observer?
Waves are the children of the struggle between ocean and atmosphere, the ongoing signatures of infinity. Rays from the sun excite and energize the atmosphere of the earth, awakening it to flow, to movement, to rhythm, to life. The wind then speaks the message of the sun to the sea and the sea transmits it on through waves -- an ancient, exquisite, powerful message.
These ocean waves are among the earth's most complicated natural phenomena. The basic features include a crest (the highest point of the wave), a trough (the lowest point), a height (the vertical distance from the trough to the crest), a wave length (the horizontal distance between two wave crests), and a period (which is the time it takes a wave crest to travel one wave length).
Although an ocean wave gives the impression of a wall of water moving in your direction, in actuality waves move through the water leaving the water about where it was. If the water was moving with the wave, the ocean and everything on it would be racing in to the shore with obviously catastrophic results.
An ocean wave passing through deep water causes a particle on the surface to move in a roughly circular orbit, drawing the particle first towards the advancing wave, then up into the wave, then forward with it and then -- as the wave leaves the particles behind -- back to its starting point again.
From both maturity to death, a wave is subject to the same laws as any other 'living' thing. For a time it assumes a miraculous individuality that, in the end, is reabsorbed into the great ocean of life.
The undulating waves of the open sea are generated by three natural causes: wind, earth movements or tremors, and the gravitational pull of the moon and the sun. Once waves have been generated, gravity is the force that drives them in a continual attempt to restore the ocean surface to a flat plain.
from World Magazine (BBC Enterprises)
New words and expressions 生词和短语
signature
n. 签名，标记
infinity
n. 无穷
ray
n. 光线
energize
v. 给与...能量
rhythm
n. 节奏
transmit
v. 传送
exquisite
phenomena
n. 现象
crest
n. 浪峰
trough
n. 波谷
vertical
horizontal
actuality
n. 现实
catastrophic
particle
n. 微粒
maturity
n. 成熟
undulate
v. 波动，形成波浪
tremor
n. 震颤
gravitational
海浪是大海和空气相斗的产物，无限的一种不间断的标志。太阳光刺激了地球的大气层，并给予它能量；阳光使空气开始流动，产生节奏，获得生命。然后，风把太阳的住处带给了大海，海洋用波浪的形式传递这个信息 -- 一个源过流长、高雅而有力的信息。
这些海浪属于地球上最复杂的自然现象。它们的基本特征包括浪峰（波浪的最高点）、波谷（最低点）、浪高（从波谷到浪峰的垂直距离）、波长（两个浪峰间的水平距离）和周期（海峰走过一个波长所需的时间）。虽然，海浪给人的印象是一堵由水组成的墙向你压过来，而实际上，浪从水中移过，而水则留在原处。如果水和浪一起移动的话，那么大海和海里所有的东西就会向岸边疾涌过来，带来明显的灾难性后果。
穿过深水的海浪使水面上的一个微粒按照一种近乎圆形的轨道移动，先把微粒拉向前移动的海浪，然后推上波浪，随着波浪移动，然后 -- 当波浪把微粒留在身后时 -- 又回到出发点。
从成熟到消亡，波浪和其他任何“活动中”的东西一样，都受制于共同的法则。一度它获得非凡的个性，但最终又被重新融进生命的大洋。
公海上起伏的波浪是由3个自然因素构成的：风、地球的运动或震颤和月亮、太阳的引力。一旦波浪形成，地球引力是持续不断企图使海面复原为平面的力量。
Lesson 41
Training elephants
训练大象
First listen and then answer the following question.
At what point does the training of a captive wild elephant begin?
Two main techniques have been used for training elephants, which we may respectively the tough and the gentle. The former method simply consists of setting an elephant to work and beating him until he does what is expected of him. Apart from moral considerations this is a stupid method of training, for it produces a resentful animal who at a later stage may well turn man-killer. The gentle method requires more patience in the early stages, but produces a cheerful, good-tempered elephant who will give many years of loyal service.
The first essential in elephant training is to assign to the animal a single mahout who will be entirely responsible for the job. Elephants like to have one master just as dogs do, and are capable of a considerable degree of personal affection. There are even stories of half-trained elephant calves who have refused to feed and pined to death when by some unavoidable circumstance they have been deprived of their own trainer. Such extreme cases must probably be taken with a grain of salt, but they do underline the general principle that the relationship between elephant and mahout is the key to successful training.
The most economical age to capture an elephant for training is between fifteen and twenty years, for it is then almost ready to undertake heavy work and can begin to earn its keep straight away. But animals of this age do not easily become subservient to man, and a very time man, and a very firm hand must be employed in the early stages. The captive elephant, still roped to a tree, plunges and screams every time a man approaches, and for several days will probably refuse all food through anger and fear. Sometimes a tame elephant is tethered nearby to give the wild one confidence, and in most cases the captive gradually quietens down and begins to accept its food. The next stage is to get the elephant to the training establishment, a ticklish business which is achieved with the aid of two tame elephants roped to the captive on either side.
When several elephants are being trained at one time, it is customary for the new arrival to be placed between the stalls of two captives whose training is already well advanced. It is then left completely undisturbed with plenty of food and water so that it can absorb the atmosphere of its new home and see that nothing particularly alarming is happening to its companions. When it is eating normally, its own training begins. The trainer stands in front of the elephant holding a long stick with a sharp metal point. Two assistants, mounted on tame elephants, control the captive from either side, while others rub their hands over his skin to the accompaniment of a monotonous and soothing chant. This is supposed to induce pleasurable sensations in the elephant, and its effects are reinforced by the use of endearing epithets. The elephant is not son', or 'ho! my father', or 'my mother', according to the age and sex of the captive. The elephant is not immediately susceptible to such blandishments, however, and usually lashes fiercely with its trunk in all directions. These movements are controlled by the trainer with the metal-pointed stick, and the trunk eventually becomes so sore that the elephant curls it up and seldom afterwards uses it for offensive purposes.
RICHARD CARRINGTON Elephants
New words and expressions 生词和短语
technique
n. 技术
tough
resentful
assign
v. 分配，指派
mahout
n. 驯象人
calf
n. 幼仔
pine
v. 消瘦
underline
v. 着重说明，强调
keep
n. 生计
subservient
plunge
v. 向前冲
tame
tether
v. （用绳）拴
ticklish
alarming
accompaniment
n. 伴奏
soothe
v. 镇定
chant
n. 单调的歌
reinforce
v. 加强
endearing
epithet
n. 称呼
susceptible
blandishment
n. 奉承
lash
v. 猛烈地甩
curl
v. 使卷曲
驯象有两种主要的方法，我们分别称之为强硬法和温柔法。强硬法就是驱象去干活，把它打顺从为止。且不说道义问题，这本身就是一种愚蠢的训练方法，因为这种方法训练会使动物反感，在以后某个时期可能会变成伤人的动物。温柔法要求在最初阶段保持较大的耐心，但这种方法可以训练出性情愉快、脾气温顺，能忠实为人服务多年的大象。
驯象中至关生要的是指派一名专门的驯象员，全面负责这项工作。大象和狗一样，喜欢有一个专一的主人，而且会对主人产生相当深厚的私人感情。甚至有这样的故事：训练了一半的小象，由于不可避免的情况与他们的主人分离后，竟拒绝吃食，消瘦至死。这种极端的事例虽不可全信，但强调了一项基本原则，象和驯象员之间的关系是驯象成功与否的关健。
捕捉15至20岁之间年龄的大象进行驯象最为经济。 这个年龄的象差不多已能干重活，可以很快挣回饲养它的开支。但这个年龄的象不易驯服，因此开始阶段需要有一位强有力的老手。捕来拴在树上的大象，每当有人走近它时，就会向前猛冲并发出尖叫，甚至一连几于都由于愤怒和恐惧而拒绝进食。有时，把一头已驯服的象拴在旁边能给野象以信心。在大多数情况下，刚博来的象会慢慢静下来，接着开始吃食。下一步就是把象带到训练场所，这是一件棘手的事，需要在它两侧拴上两头驯服的大象才能完成。
几只象同时训练时，通常是把新到的安置在两头训练得很好的大象的象厩中间，然后给它以充足的食物和水，一定不要惊扰它，以便让他能适应新居的气氛，并且看到自己的同伴身上没有发生让自己担惊受怕的事。当它进食正常了，训练就开始。驯练员手持一根有锋利金属尖头的长棒，站在象前。两位助手骑在驯服的象的背上，从两侧控制新捕的象，其他人唱着单调的歌声用手抚摸象的皮肤。据说这是为了使象产生愉快的感觉，为了加强这种效果，人闪还按象的年龄性别，给以亲切的外号，如“嗬！我的孩子”、“嗬！我的爸爸”、“嗬！我的妈妈”。然而大象不会立刻被这些讨好的括感动，而往往是用鼻子朝各个方向猛烈地甩动。训练员要用有锋利金属尖的长棒控制它的这种举动，象鼻子最后疼得卷了起来，以后它就很少用鼻子去进攻了。
Lesson 42
Recording an earthquake
记录地震
First listen and then answer the following question.
What does a pen have to do to record on paper the vibrations generated by an earthquake?
An earthquake comes like a thief in the night, without warning. It was necessary, therefore, to invent instruments that neither slumbered nor slept. Some devices were quite simple. One, for instance, consisted of rods of various lengths and thicknesses with would stand up end like ninepins. When a shock came, it shook the rigid table upon which these stood. If it were gentle, only the more unstable rods fell. If it were severe, they all fell. Thus the rods, by falling, and by the direction in which they fell, recorded for the severe, they all fell. Thus the rods, by falling, and by the direction in which they fell, recorded for the slumbering scientist the strength of a shock that was too weak to waken him, and the direction from which it came.
But instruments far more deliecate than that were needed if any really serious advance was to be made. The ideal to be aimed at was to devise an instrument that could record with a pen on paper, the movements of the ground or of the table as the quake passed by. While I write my pen moves, but the paper keeps still. With practice, no doubt, I could in time learn to write by holding the pen still while the paper moved. That sounds a silly suggestion, but that was precisely the idea adopted in some of the early instruments (seismometers) for recording earthquake waves. But when table, penholder and paper are all moving, how is it possible to write legibly? The key to a solution of that problem lay in an everyday observation. Why does a person standing in a bus or train tend to fall when a sudden start is made? It is because his feet move on , but his head stays still. A simple experiment will help us a little further. Tie a heavy weight at the end of a long piece of string. With the hand to and fro and around but not up and string so that the weight nearly touches the ground. Now move the hand to and fro and around but not up and down. It will be found that the weight a piece of string. With the hand held high in the air, hold the string so that the weight nearly touches the ground. Now move the hand to and fro and around but not up and down. It will be found that ten weight moves but slightly or not at all. Imagine an earthquake shock shaking the floor, the paper, you and your hand. In the midst of all this movement, the weight and the pen would be still. But as the paper moved from side to side under the pen point, its movement would be recorded in ink upon its surface. It was upon this principle that the first instruments were made, but while the drum was being shaken, the line that the pen was drawing wriggled from side to side. The apparatus thus described, however, records only the horizontal component of the wave movement, which is, in fact, much more complicated. If we could actually see the path described by a particle, such as a sand grain in the rock, it would be more like that of a bluebottle path described by a particle, such as a sand grain in the rock, it would be more like that of a bluebottle buzzing round the room; it would be up and down, to and fro and from side to side. Instruments have been devised and can be so placed that all three elements can be recorded in different graphs.
When the instrument is situated at more than 700 miles from the earthquake centre, the graphic record shows three waves arriving one after at short intervals. The first records the arrival of longitudinal vibrations. The second marks the arrival of transverse vibrations which travel more slowly and arrive several minutes after the first. These two have travelled through the earth. It was from the study of these that so much was learnt about the interior of the earth. The third, or main. The third, or main wave, is the slowest and has travelled round the earth through the surface rocks.
H.H,SWINNERTON The Earth beneath Us
New words and expressions 生词和短语
earthquake
n. 地震
slumber
v. 睡眠
ninepin
n. 九柱戏中的木柱
rigid
delicate
seismometer
n. 地震仪
penholder
n. 笔杆
legibly
drum
n. 鼓状物
wriggle
v. 扭动
bluebottle
n. 绿头苍蝇
graph
n. 图表
graphic
longitudinal
transverse
地震就像夜间的小偷，不打招呼就来了。因此，有必要发明一种仪器，既不打盹儿，也不睡觉。有些装置非常简单。例如，有一种装置是由一些长短、粗细不同的木棒组成，就像九柱戏的木棒一样坚立着，一旦有地震，就会震动竖立在坚硬的桌上的木棒。如果地震轻微，只有不稳定的木棒倒下；如果地震剧烈，所有的木棒都会例下。由于地震太弱而未惊醒科学家时，木棒倒下的多少和倒下的方向就为科学家记录下了地震的强度和地震方向。
但是，如果要取得真正重大的进展，需要有比这种装置精细得多的仪器。理想的目标是设计出这样一种仪器：当地震发生时，它能用笔在纸上记录下大地和桌子运动情况。我写字时，笔是移动的，纸是静止的。毫无疑问，经过练习，我最终能够学会笔不动而纸动来写字。这听起来似乎是一种愚蠢的想法，但是早期记录地震波的仪器（地震仪）正是采用了这中思路。可是，当桌子、夹笔装置、纸都在移动时，怎么能书写得清楚呢？可以从我们的日常生活观察中找到这个问题的答案。一个站在公共汽车或火车上，当车突然开动时，他为什么会倾倒呢？这是因为他的脚动了，而他的头保持着静止。再做一个简单的实验可以帮助我们进一步理解这个问题。把一个生物拴在一根长绳子的一端，把手高高举在空中握住绳子，让重物几乎接触地面。然后把手前后左右以及旋转摆动，但不要上下摆动。结果会发现，重物是动了，但动得很小，甚至没动。假定把一支笔拴在重物上，笔尖落在地板上的一张纸上，假定地震发生了，地板、纸、你和你的手都会动，重物和笔却不动。由于纸在笔下来回运动，纸的表面就会用墨水记录下地板运动的情况。根据这一原理，制造出了最初的地震仪器，但是纸是卷在慢慢放置的圆筒上的。只要一切都是静止的，笔就会划出一条直线；但是，圆筒受到震动，笔所画出的线就会就会左右摆动。然而，这里所说的仪器记录下来的只是地震波运动中的水平部份，地震波的运动实际比这要复杂得多。假如我们真能看到诸如岩石中一个沙粒子的运动轨迹，那就像一只嗡嗡叫的绿头苍蝇在屋内飞行的轨迹，呈现出上上下下、来来回回、左左右右3种性质的运动。已经设计出了一些仪器，它按照一定的安放方式就可测绘出这三种运动的曲线图。
如果把这种仪器安装在距震源700多英里远的地方，曲线记录就能显示出前后相同的这3种地震波。首先记录下的是纵向波的到达；然后记录下的是横向波的到达，横向波比纵向波传播得慢，在纵向波到过几分钟后能到达。这珍两种波都是穿过地球而来的。正是从这两种波中的研究中，我们可以了解到地球内部的许多情况。第三种波，即主波，是最慢的，是围绕地球通过表面岩石传来的。
Lesson 43
Are there strangers in space?
宇宙中有外星人吗？
First listen and then answer the following question.
What does the 'uniquely rational way' for us to communicate with other intelligent beings in space depend on?
We must conclude from the work of those who have studied the origin of life, that given a planet only approximately like our own, life is almost certain to start. Of all the planets in our solar system, we ware now pretty certain the Earth is the only one on which life can survive. Mars is too dry and poor in oxygen, Venus far too hot, and so is Mercury, and the outer planets have temperatures near absolute zero and hydrogen-dominated atmospheres. But other suns, start as the astronomers call them, are bound to have planets like our own, and as is the number of stars in the universe is so vast, this possibility becomes virtual certainty. There are one hundred thousand million starts in our own Milky Way alone, and then there are exist is now estimated at about 300 million million.
Although perhaps only 1 per cent of the life that has started somewhere will develop into highly complex and intelligent patterns, so vast is the number of planets, that intelligent life is bound to be a natural part of the universe.
If then we are so certain that other intelligent life exists in the universe, why have we had no visitors from outer space yet? First of all, they may have come to this planet of ours thousands or millions of years ago, and found our then prevailing primitive state completely uninteresting to their own advanced knowledge. Professor Ronald Bracewell, a leading American radio astronomer, argued in Nature that such a superior civilization, on a visit to our own solar system, may have left an automatic messenger behind to await the possible awakening of an advanced civilization. Such a messenger, receiving our radio and television signals, might well re-transmit them back to its home-planet, although what impression any other civilization would thus get from us is best left unsaid.
But here we come up against the most difficult of all obstacles to contact with people on other planets -- the astronomical distances which separate us. As a reasonable guess, they might, on an average, be 100 light years away. (A light year is the distance which light travels at 186,000 miles per second in one year, namely 6 million million miles.) Radio waves also travel at the speed of light, and assuming such an automatic messenger picked up our first broadcasts of the 1920's, the message to its home planet is barely halfway there. Similarly, our own present primitive chemical rockets, though good enough to orbit men, have no chance of transporting us to the nearest other star, four light years away, let alone distances of tens or hundreds of light years.
Fortunately, there is a 'uniquely rational way' for us to communicate with other intelligent beings, as Walter Sullivan has put it in his excellent book, We Are not Alone. This depends on the precise radio frequency of the 21-cm wavelength, or 1420 megacycles per second. It is the natural frequency of emission of the hydrogen atoms in space and was discovered by us in 1951; it must be known to any kind of radio astronomer in the universe.
Once the existence of this wave-length had been discovered, it was not long before its use as the uniquely recognizable broadcasting frequency for interstellar communication was suggested. Without something of this kind, searching for intelligences on other planets would be like trying to meet a friend in London without a pre-arranged rendezvous and absurdly wandering the streets in the hope of a chance encounter.
ANTHONY MICHAELIS Are There Strangers in Space? from The Weekend Telegraph
New words and expressions 生词和短语
Mercury
n. 水星
hydrogen
n. 氢气
prevailing
射电天方学家
uniquely
rational
无线电频率
cm
n. 厘米
megacycle
n. 兆周
emission
n. 散发
intersteller
rendezvous
n. 约会地点
根据研究生命起源的人们所作的工作，我们必然会得出这样的结论：如果设想有一颗行星和我们地球的情况基本相似，那几乎肯定会产生生命。我们目前可以肯定的是，在我们太阳系的所有行星中，地球是生命能存在的唯一行星。火星太干燥又缺氧，金星太热，水星也一样。除此之外，太阳系的其他行星的温度都接近绝对零度，并围绕着以氢气为主的大气层。但是，其他的太阳，既天文学家所说的恒星，肯定会有像我们地球一样的行星。因为宇宙中恒星的数目极其庞大，所以存在着产生生命星球的这种可能性是肯定无疑的。仅我们的银河系就有1000亿颗星，况且在宇宙中还有30亿个天河，即银河系。因此，我们所知道的现有恒星数目估计约有30亿X1000亿颗。
虽然在已经产生生命的某个地方，可能只有1%会发展成高度复杂有智力的生命形态，但是行星的数目是那么庞大，有智力的生命必然是宇宙的自然组成道听部分。
既然我们如此坚信宇宙中存在着其他有智力的生命，那么我们为什么还未见到外层空间来访的客人呢？首先，他们可能在几千年前或几百年前已来过我们地球，并且发现我们地球汉时普遍存在着的原始状态同他们的先进的知识相比是索然无味的。美国一位重要的射电天文学家罗纳德.布雷斯韦尔教授在《自然》杂志上提出了这样的观点：假如有如此高级文明生命访问了我们的太阳系，很可能会在离开太阳系时留下自动化信号装置，等待先进文明的觉醒。这种自动化信息装置，在接收到我们的无线电和电视信号后，完全有可能把这些信号发回到原来的行星。至于其他文明行星对我们地球会有什么印象，还是不说为好。
然而，在和外星人联系中我们遇到的最大困难是分隔我们的天文距离。据合理推算，外星人离我们平均距离也有100光年之远（1光年是光以每秒186，000英里的速度在一年内走的距离即6万亿英里）。无线电波也是以光速传播的。假定外星人的这种自动化信息装置接收了我们二十世纪二十年代的第一次广播信号，那么这个信号在发回到原来的行星途中刚刚走了一半路程。同样，我们目前使用的原始化学火箭，虽然把人送入轨道，但尚不能把我们送到离我们最近、相距4光年的其他星球上去，更不用说几十光年或几百光年远的地方了。
幸运的是，有一种我们可以和其他智力生命通迅联系的“唯一合理的方法”，正如活尔特.沙利方在其杰作《我们并不孤独》中阐述的。这种通迅联系要靠21厘料波段，即每秒1420兆周的精确无线电频率。这个频率是空间氢原子释放的自然频率，是在1951年被人类发现的。这个频率是宇宙中任何射电天文学家都应该熟悉的。
一旦这种波长的实际存在被发现，提出把它作为星际间唯一可辨认的广播频率就为期不远了。没有这手段，要想寻觅其他星球上的智力生命，就如同去伦敦见一位朋友，事先未约定地点，而荒唐地在街上游逛，以期待碰巧遇上一样。
Lesson 44
Patterns of culture
文化的模式
First listen and then answer the following question.
What influences us from the moment of birth?
Custom has not commonly been regarded as a subject of great moment. The inner workings of our won brains we feel to be uniquely worthy of investigation, but custom, we have a way of thinking, is behaviour at its most commonplace. As a matter of fact, it is the other way around. Traditional custom, taken the world over, is a mass of detailed behaviour more astonishing than what any one person can ever evolve in individual actions, no matter how aberrant. Yet that is a rather trivial aspect of the matter. The fact of first-rate importance is the predominant role that custom plays in experience and in belief, and the very great varieties it may manifest.
No man ever looks at the world with pristine eyes. He sees it edited by a definite set of customs and institutions and ways of thinking. Even in his philosophical probing he cannot go behind these stereotypes; his very concepts of the true and the false will still have reference to his particular traditional customs. John Dewey has said in all seriousness that the part played by custom in shaping the behaviour of the individual, as against any way in which he can affect traditional custom, is as the proportion of the total vocabulary of his mother tongue against those words of his own baby talk that are taken up into the vernacular of his family. When one seriously studies the social orders that have had the opportunity to develop autonomously, the figure becomes no more than an exact and matter-of-fact observation. The life history handed down in his community. From the moment of his birth, the customs into which he is born shape his experience and behaviour. By the time he can talk, he is the little creature of his culture, and by the time he is grown and able to take part in its activities, its habits are his habits, its beliefs his beliefs, its impossibilities his impossibilities. Every child that is born into his group will share them with him, and no child born into one on the opposite side of the globe can ever achieve the thousandth part. There is no social problem it is more incumbent upon us to understand than this of the role of custom. Until we are intelligent as to its laws and varieties, the main complicating facts of human life must remain unintelligible.
The study of custom can be profitable only after certain preliminary propositions have been accepted, and some of these propositions have been violently opposed. In the first place, any scientific study requires that there be no preferential weighting of one or another of the items in the series it selects for its consideration. In all the less controversial fields, like the study of cacti or termites or the mature of nebulae, the necessary method of study is to group the relevant material and to take note of all possible variant forms and conditions. In this way, we have learned all that we know of the laws of astronomy, or of the habits of the social insects, let us say. It is only in the relevant material and to take note of all possible variant forms and conditions. In this way, we have learned all that we know of the laws of astronomy, or of the habits of the social insects, let us say. It is only in the study of man himself that the major social sciences have substituted the study of one local variation, that of Western civilization.
Anthropology was by definition impossible, as long as these distinctions between ourselves and the primitive, ourselves and the barbarian, ourselves and the pagan, held sway over people's minds. It was necessary first to arrive at that degree of sophistication where we no longer set our own belief against our neighbour's superstition. It was necessary to recognize that these institutions which are based on the same premises, let us say the supernatural, must be considered together, our own among the rest.
RUTH BENEDICT Patterns of Culture
New words and expressions 生词和短语
commonplace
aberrant
trivial
predominant
manifest
v. 表明
pristine
stereotype
n. 陈规
vernacular
n. 方言
accommodation
n. 适应
incumbent
preliminary
proposition
n. 主张
preferrential
controversial
cactus
n. 仙人掌
termite
n. 白蚁
nebula
variant
n. 不同的
barbarian
n. 野蛮人
pagan
n. 异教徒
sophistication
n. 老练
premise
n. 前提
supernatural
风俗一般未被认为是什么重要的课题。我们觉得，只有我们大脑内部的活动情况才值得研究，至于风俗呢，只是些司空见惯的行为而已。事实小，情况正好相反。从世界范围来看，传统风俗是由许多细节性的习惯行为组成，它比任何一个养成的行为都更加引人注目，不管个人行为多么异常。这只是问题的一个次要的侧面。最重要的是，风俗在实践中和信仰上所起的举足轻重的作用，以及它所表现出来的极其丰富多采的形式。
没有一个人是用纯洁而无偏见的眼光看待世界。人们所看到的是一个受特定风俗习惯、制度和思想方式剪辑过的世界。甚至在哲学领域的探索中，人们也无法超越这此定型的框框。人们关于真与伪的概念依然和特定的传统风俗有关。约翰.杜威曾经非常严肃地指出：风俗在形成个人行为方面所起的作用和一个对风俗的任何影响相比，就好像他本国语言的总词汇量和自己咿呀学语时他家庭所接纳的他的词汇量之比。当一个人认真地研究自发形成的社会秩序时，杜威的比喻就是他实事求是观察得来的形象化的说法。个人的生活史首先是适应他的社团世代相传形成的生活方式和准则。从他呱呱坠地的时刻起，他所生于其中的风俗就开始塑造他的经历和行为规范。到会说话时，他就是传统文化塑造的一个小孩子；等他长大了，能做各种事了，他的社团的习惯就是他的习惯，他的社团的信仰就是他的信仰，他的社团不能做的事就是他不能做的事。每一个和他诞生在同一个社团中的孩子和他一样具有相同的风俗；而在地球的另一边。诞生在另一个社团的孩子与他就是少有相同的风俗。没有任何一个社会问题比得上风俗的作用问题更要求我们对它理解。直到我们理解了风俗的规律性和多样性，我们才能明白人为生活中主要的复杂现象。
只有在某些基本的主张被接受下来、同时有些主张被激烈反对时，对风俗的研究才是全面的，才会有收获。首先，任何科学研究都要求人们对可供考虑的诸多因素不能厚此薄彼，偏向某一方面。在一切争议较小的领域里，如对仙人掌、白议或星云性质的研究，应采取的研究方法是。把有关各方面的材料汇集起来，同时注意任何可能出现的异常情况和条件。例如，用这种方法，我们完全掌握了天文学的规律和昆虫群居的习性。只是在对人类自身的研究。只要我们同原始人，我们同野蛮人，我们同异教徒之间存有的区别在人的思想中占主工导地位，那么人类学按其定义来说就无法存在。我们首先需要达到这样一种成熟的程度：不用自己的信仰去反对我们邻居的迷信。必须认识到，这些建立在相同前提基础上的风俗，暂且可以说是超自然的东西，必须放在一起加以考虑，我们自己的风俗和其他民族的风俗都在其中。
Lesson 45
Of men and galaxies
人和星系
First listen and then answer the following question.
What is the most influential factor in any human society?
In man's early days. competition with other creatures must have been critical. But this phase of our development is now finished. Indeed, we lack practice and experience nowadays in dealing with primitive conditions. I am sure that, without modern weapons, I would make a very poor show of disputing the ownership of a cave with a bear, and in this I do not think that I stand alone. The last creature to compete with man was the mosquito. But even the mosquito has been subdued by attention to drainage and by chemical sprays.
Competition between our selves, person against person, community against community, still persists, however; and it is as fierce as it ever was.
But the competition of man against man is not the simple process envisioned in biology. It is not a simple competition for a fixed amount of food determined by the physical environment, because the environment that determines our evolution is no longer essentially physical. Our environment is chiefly conditoned by the things we believe. Morocco and California are bits of the Earth in very similar latitudes, both on the west coasts of continents with similar climates, and probably with rather similar natural resources. Yet their present development is wholly different, not so much because of different people wish to emphasize. The most important factor in our environment is the state of our own minds.
It is well known that where the white man has invaded a primitive culture, the most destructive effects have come not from physical weapons but from ideas. Ideas are dangerous. The Holy Office knew this full well when it caused heretics to be burned in days gone by. Indeed, the concept of free speech only exists in our modern society because when you are inside a community, you are conditioned by the conventions of the community to such a degree that it is very difficult to conceive of anything really destructive. It is only someone looking on from outside that can inject the dangerous thoughts. I do not doubt that it would be possible to inject ideas into the modern world that would utterly destroy us. I would like to give you an example, but fortunately I cannot do so. Perhaps it will suffice to mention the unclear bomb. Of making the effect on a reasonably advanced technological society, one that still does not possess the bomb, of making it aware of the possibility, of supplying sufficient details to enable the thing to be constructed. Twenty or thirty pages of information handed to any of the major world powers around the year 1925 would have been sufficient to change the course of world history. It is a strange thought, but I believe a correct one, that twenty or thirty pages of ideas and information would be capable of turning the present-day world upside down, or even destroying it. I have often tried to conceive of what those pages might contain, but of course outside the particular patterns that our brains are conditioned to, or, to be more accurate, we can think only a very little way outside, and then only if we are very original.
FRED HOYLE Of Men and Galaxies
New words and expressions 生词和短语
dispute
v. 争夺
mosquito
n. 蚊子
subdue
v. 征服
drainage
n. 下水系统
envision
n. 预想
Morocco
n. 摩洛哥
latitude
n. 纬度
heretic
n. 异教徒，异端邪说
conceive
v. 想像
suffice
v. 足够
nuclear
original
在人类早期，人类与其他生物的竞争一定是必不可少的。但这个发展阶段已经结束。确实，我们今天缺乏对付原始环境的实践和经验。我断定，如果没有现代化的武器，要我和一只熊去争洞穴，我会出洋相的；我也相信，出洋相者并非我一人。能与竞争的生物最后只有蚊子，然而即使蚊子，也由于我们注意清理污水和喷洒化学药品就被制服了。
然而人类之间的战争，人与人，团体与团体，依然在进行着，而且和以前一样激烈。
但是，人与人的竞争并不像生物生物学中想像的那样是一个简单过程。它已不是为争得物质环境所决定的东西所决定。摩洛哥和加利福尼亚是地球上纬度极其相似的两个地方，都在各自大陆的西海岸，气候相似，自然资源也可能相似。但是，这两个地方目前的发展程度完全不一样。这倒不是因为人民不同，而是由于居民头脑中的思想不同。 这是我要强调的论点。我们环境中最重要的因素就是我们的思想状况。
众所周知，凡是白人侵入原始文化的地方，破坏作用最大的不是杀人的武器，而是思想。思想是危险的。宗教法庭对此是非常清楚的，因此从前它总是把异教徒烧死。的确，言论自由的概念只存在于我们现代社会中，因为当你生活在一个社团中时，社团的风俗习惯会严格地制约你，使你很难有破坏性的想法。只有外部的旁观者才能灌输危险的思想。向现代世界灌输一种思想以便摧毁我们人类是可能的事，对此我并不怀疑。我愿为你举个例子，但幸亏我举不出。也许提一下核弹就足以证明了。对一个沿未拥有核弹、但科技相当发达的社会，如果告诉它制造核弹的可能性，而且向它提供制造核弹的细节，那么可以设想，这将对这个社会产生何等的影响。如果把二三十页的情报交给1952年前后的任何一个世界强国，就足以改变世界历史的进程。二三十页材料中的思想和情报会便当今的世界翻天覆地，甚至毁灭这个世界。这是个离奇的想法。不过我认为这个想法是正确的。我常常试图想像这些纸上所写的东西，不过我是做不到的，因为我和你们大家一样，是当今世界上的凡人。我闪不能脱离我们大脑所限定的模式去问题，我们只能稍微离开一点儿，就这也需要我们独创的思想。
Lesson 46
Hobbies
业余爱好
First listen and then answer the following question.
Who, according to the author, are 'Fortune's favoured children'?
a gifted American psychologist has said, 'Worry is a spasm of the emotion; the mind catches hold of something and will not let it go.' It is useless to argue with the mind in this condition. The stronger the will, the more futile the task. One can only gently insinuate something else into its convulsive grasp. And if this something else is rightly chosen, if it really attended by the illumination of another field of interest, gradually, and often quite swiftly, the old undue grip relaxes and the process of recuperation and repair begins.
The cultivation of a hobby and new forms of interest is therefore a policy of the first importance to a public man. But this is not a business that can be undertaken in a day or swiftly improvised by a mere command of the will. The growth of alternative mental interests is a long process. The seeds must by carefully chosen; they must fall on good ground; they must be sedulously tended, if the vivifying fruits are to be at hand when needed.
To be really happy and really safe, one ought to have at least two or three hobbies, and they must all be real. It is no use starting late in life to say: 'I will take an interest in this or that.' Such an attempt only aggravates the strain of mental effort. A man may acquire great knowledge of topics unconnected with his daily work, and yet get hardly any benefit or relief. It is no use doing what you like; you have got to like what you do. Broadly speaking, human beings may be divided into three classes: those who are toiled to death, those who are worried to hard week's sweat and effort, the chance of playing a game of football or baseball or Saturday afternoon. It is no use inviting the politician or the professional or business man, who has beer working or worrying about serious things for six days, to work or worry about trifling things at the weekend.
As for the unfortunate people who can command everything they want, who can gratify every caprice and lay their hands on almost every object of desire -- for them a new pleasure, a new excitement if only an additional satiation. In vain they rush frantically round from place to place, trying to escape from avenging boredom by mere clatter and motion. For them discipline in one form or another is the most hopeful path.
It may also be said that rational, industrious, useful human being are divided into two classes: first, one. Of these the former are the majority. They have their compensations. The long hours in the office or the factory bring with them as their reward, not only the means of sustenance, but a keen appetite for pleasure even in its simplest and most modest forms. But Fortune's of sustenance, but a keen appetite for pleasure even in its simplest and modest forms. But Fortune's favoured children belong to the second class. Their life is a natural harmony. For them the working hours are never long enough. Each day is a holiday, and ordinary holidays, when they come, are grudged as enforced as enforced interruptions in an absorbing vocation. Yet to both classes, the need of an alternative outlook, of a change of atmosphere, of a diversion of effort, is essential. Indeed, it may well be that those work is their pleasure are those who and most need the means of banishing it at intervals from their minds.
WINSTON CHURCHLL Painting as a Pastime
New words and expressions 生词和短语
psychologist
n. 心理学家
spasm
n. 一阵（感情）发作
futile
insinuate
v. 便潜入，暗示
convulsive
illumination
n. 启发，照明
undue
grip
n. 紧张
recuperation
n. 休息
improvise
v. 临时作成
sedulously
vivify
v. 使生气勃勃
aggravate
v. 加剧
trifling
gratify
v. 便满意
caprice
n. 任性
satiation
n. 满足
frantically
avenge
v. 替…报复
boredom
n. 厌烦
clatter
n. 喧闹的谈话
sustenance
n. 生计
appetite
n. 欲望
grudge
v. 怨恨
absorbing
banish
v. 排除，放弃
一位天才的美国心理学家曾经说过：“烦恼是感情的发作，此时脑子纠缠住了某种东西又不肯松手。”在这种情况下，你又和头脑争吵让它松手是无济于事的。这种意志越是强烈，这种尝试越是徒劳。你只能缓和而巧纱地让另一种东西进入痉挛僵持的头脑中。如果选得合适，而且的确受到别的领域的情趣的启迪，那么渐渐地，往往也是很顺利地，原先不适当的紧张就会松弛下来，恢复和修整的过程就会开始。
因此，对一个从事社会活动的人来说，培养一种业余爱好和各种新的兴趣是关等重要的作法。但这并非一日之功，也不是单凭一蹴而就的事。精神上多种情趣的培养是一个长期的过程。要想在需要的时候可随手摘取充满生机的果实，那就必然从选良种做起，然后将其植入肥沃的土地，还需要勤勉地护理。
一个人要想真正感到幸福和平安，至少应有两三种爱好，而且都比较实际。到了晚年才开始说：“我会对这些人或那个人发生兴趣”，已没有用了。这种愿望只能加剧精神紧张。一个人可能会获得与其日常工作无关的某些课题的渊博知识，而没有从中得到什么实益或宽慰。干你所喜欢的事是没有用的，你喜欢你所干的事。泛泛地说，人可以分为3类：劳累至死的人、忧虑至死的人、无聊至死的人。对于流汗出力干了一周苦活的体力劳动者来说，让他们在星期六下午再踢足球或打垒球是不合适的；同样，对于为严肃的公务操劳或烦恼了6天的政界人士、专业人员、商人来说，在周未再让他们为琐事而动脑子和忧虑也是无益的。
至于那些能任意支配一切的“可怜的人”，他们能够恣意妄为，能染指一切追求的目标。对这种人来说，多一种新的乐趣、多一种新的刺激只是增加一分厌腻而已。他们到处奔乱跑，企图以闲聊和乱窜来摆脱无聊对他们的报复，但这是徒劳的。对他们来说，用某种形式的纪律约束他们一下才能有希望使他们走上正道。
也可以这样说，理智的，勤劳的、有用的人可以分为两类：第一类是他分清工作是工作，娱乐是娱乐的人；第二类人的工作和娱乐是一回事。这两类人当中，第一类人是大多数，他们能够得到补偿。在办公室或工厂里长时间工作给他们带来了酬劳，这不仅是谋生的手段，而且还带来了寻找乐趣的强烈欲望，那怕是最简单的、最低等的乐趣。但是，命运之神的宠儿是第二类人，他们的生活是一种自然的和谐，对他们来说，工作时间总不会太长，每天都是假日，而通常的假期来到，他们却惋惜这假期强制打断了他们埋头从事的工作。然而对这两种人来说，都需要换一换脑子，改变一下气氛，转移一下注意力，这是不可缺少的。说实在的，把工作当作享受的那些人最需要每隔一段时间把工作从头脑中撇开。
Lesson 47
The great escape
大逃亡
First listen and then answer the following quesion.
What is one of the features of modern camping where nationality is concerned?
Economy is one powerful motive for camping, since after the initial outlay upon equipment, or through hiring it, the total expense can be far less than the cost of hotels. But, contrary to a popular assumption, it is far from being the only one, or even the greatest. The man who manoeuvres carelessly into his twenty pounds' worth of space at one of Europe's myriad permanent sites may find himself bumping a Bentley. More likely, Ford Escort will be hub to hub with Renault or Mercedes, but rarely with bicycles made for two.
That the equipment of modern camping becomes yearly more sophisticated is an entertaining paradox for the cynic, a brighter promise for the hopeful traveler who has sworn to get away from it all. It also provides-and some student sociologist might care to base his thesis upon the phenomenon -- an escape of another kind. The modern traveller is often a man who dislikes the Splendide and the Bellavista, not because he cannot afford, or shuns their material comforts. but because he is afford of them. Affluent he may be, but he is by no means sure what to tip the doorman or the chambermaid. Master in his own house, he has little idea of when to say boo to a maitre d'hotel.
From all such fears camping releases him. Granted, a snobbery of camping itself, based upon equipment and techniques, already exists; but it is of a kind that, if he meets it, he can readily understand and deal with. There is no superior 'they' in the shape of managements and hotel hierarchies to darken his holiday days.
To such motives, yet another must be added. The contemporary phenomenon of car worship is to be explained not least by the sense of independence and freedom that ownership entails. To this pleasure camping gives an exquisite refinement.
From one's own front door to home or foreign hills or sands and back again, everything is to hand. Not only are the means of arriving at the holiday paradise entirely within one's own command and keeping, but the means of escape from holiday hel (if the beach proves too crowded, the local weather too inclement) are there, outside -- or, as likely, part of -- the tent.
Idealists have objected to the package tour, that the traveller abroad thereby denies himself the opportunity of getting to know the people of the country visited. Insularity and self-containment, it is argued, go hand in hand. The opinion does not survive experience of a popular Continental camping place. Holiday hotels tend to cater for one nationality of visitors especially, sometimes exclusively. Camping sites, by contrast, are highly cosmopolitan. Granted, a preponderance of Germans is a characteristic that seems common to most Mediterranean sites; but as yet there is no overwhelmingly specialized patronage. Notices forbidding the open-air drying of clothes, or the use of water points for car washing, or those inviting 'our camping friends' to a dance or a boat trip are printed not only in French or Italian or Spanish, but also in English, German and Dutch. At meal times the odour of sauerkraut vies with that of garlic. The Frenchman's breakfast coffee competes with the Englishman's bacon and eggs.
Whether the remarkable growth of organized camping means the eventual death of the more independent kind is hard to say. Municipalities naturally want to secure the campers' site fees and other custom. Police are wary of itinerants who cannot be traced to a recognized camp boundary or to four walls. But most probably it will all depend upon campers themselves: how many heath fires they cause; how much litter they leave; in short, whether or not they wholly alienate landowners and those who live in the countryside. Only good scouting is likely to preserve the freedoms so dear to the heart of the eternal Boy Scout.
NIGEL BUXTON The Great Escape from The Weekend Telegraph
New words and expressions 生词和短语
assumption
n. 假定
manoeuvre
v. （驱车）移动
n. 自相矛盾的呈
cynic
n. 愤世嫉俗者
sociologist
n. 社会学家
shun
v. 避开
affluent
chambermaid
n. 女招待员
boo
b. 呸的一声
maitre d'hotel
n. [法语]总管
snobbery
n. 势利
hierarchy
n. 等级制度
entail
v. 便成为必要
inclement
package tour
由旅行社安排一切的一揽子诱游
insularity
n. 偏狭
cater
v. 迎合
exclusively
cosmopolitan
preponderance
n. 优势
overwhelmingly
patronage
n. 恩惠，惠顾
sauerkraut
n. 泡菜
vie
v. 竞争
municipality
n. 市政当局
itinerant
n. 巡回者
heath
v. 荒地
alienate
v. 便疏远
eternal
图省钱是露营的一个主要动机，因为除了开始时购置或是租借一套露营装备外，总费用算起来要比住旅馆开支少得多。但是，和一般的看法相反，这决非是仅有的，甚至不是最主要的动机。如果一位游客漫不经心地驾车驶入欧洲无数常年营地之一，花20镑租用一个空位，那么他可能会碰见一辆本特利汽车，更可能会望见一辆福特.康索尔或一辆雷诺或一辆梅塞迪斯并排停放着，不过双人自行车则不容易看到。
现代露营装备一年比一年讲究，这对那些厌世嫉俗者来说是一件有趣的自相矛盾的事情。而对于发誓用露营来摆脱烦恼的人来说，却带来了更光明的前景。学社会学的大学生来露营是另一种形式的摆脱现实，他们的目的很可能是根据观察到的露营现象去写论文。现代露营旅游的人往往讨厌在“斯普兰迪德”和“贝拉维斯塔”这样的大酒店，这并不是因为他们付不起钱，也不是为了躲避物质享受，而是因为他们害怕酒店。他们可能很富有，但给看门人和房间女服务叫多少小费，心中却根本没有数；他们在家可能是主人，但不知道什么时候才能对酒店的经理表示不满。
露营便人们免除了这些忧虑。诚然，露营地本身也存在以露营装备和方式取人的势利现象，但如果有这种情况，露营者也容易理解，知道如何对付，但在露营地里根本不会有管人的“人上人”和酒店里的等级制度来种露营者的假日过得阴郁低沉。
除上以动机外，还应加上一个。当前崇拜汽车现象可以用与所有权相伴的独立和自由意识来解释。因此开车去露营会给这种快乐意识增加一种优雅意境。
从自己的家门出发到国内国外的山区或沙滩上露营然后返回，一切都很便利。完全在自己掌握之中的私人汽车不仅是到达假日天堂的工具，而且也是逃离假日地狱（如海滩太挤，当地天气恶劣）方便工具，因为汽车就停在帐篷外面，或者汽车本身可能就是露营帐篷的一个组成部分。
理想主义者像反对旅行社安排一切的一揽子旅游一样反对露营的作法，说这种封闭的作法使到国外旅游者失去了了解所去国家人民的机会。他们争论说，心胸狭窄和自我封闭是并存的。但这种说法在受人欢迎的欧洲露营地是站不住脚的。假日旅馆有只接待来自一个国家的旅游者的倾向，有时会达到排他的程度。而露营驻地则相反，是高度世界性的。在大多数地中海露营地里，德国人占优势似乎是个普遍现象，确实如此，但并没有特别的优待。禁止露天晒衣服、禁止用水龙头冲洗汽车的布告和邀请露营朋友参加舞会、乘船观光的招贴不仅印志法语、意大利语、西班牙语，而且也印成英语、德语、荷兰语。用饭的时候，德国泡菜味和大蒜味争相散发，法国人的早点咖啡和英国人的咸肉煎蛋竞相比美。
有组织的露营活动的明显发展是否意味着较独立的自我封闭式露营的最终消失，还很难说。市政当局当然希望获得露营者的场地费和其他光临的好处，警察则对那些查不出有固定营地或住处的游荡者保持警惕。但最重要的或许是露营者自己，即他们引起了多少场野火，留下了多少垃圾。总之，他们是否弄得土地的主人和乡间的居民同他们反目。只有优良的童子军活动才能保持不朽的童子军所衷心热爱的各项自由。
Lesson 48
Planning a share portfolio
规划股份投资
First listen and then answer the following question.
How does the older investor differ in his approach to investment from the younger investor?
There is no shortage of tipsters around offering 'get-rich-quick' opportunities. But if you are a serious private investor, leave the Las Vegas mentality to those with money to fritter. The serious investor needs a proper 'portfolio' -- a well-planned selection of investments, with a definite structure and a clear aim. But exactly how does a newcomer to the stock market go about achieving that?
Well, if you go to five reputable stock brokers and ask them what you should do with your money, you're likely to get five different answers, -- even if you give all the relevant information about your age age, family, finances and what you want from your investments. Moral? There is no one 'right' way to structure a portfolio. However, there are undoubtedly some wrong ways, and you can be sure that none of our five advisers would have suggested sinking all (or perhaps any) of your money into Periwigs*.
So what should you do? We'll assume that you have sorted out the basics -- like mortgages, pensions, insurance and access to sufficient cash reserves. You should then establish your own individual aims. These are partly a matter of personal circumstances, partly a matter of psychology.
For instance, if you are older you have less time to recover from any major losses, and you may well wish to boost your pension income. So preserving your capital and generating extra income are your main priorities. In this case, you'd probably construct a portfolio with some shares (but not high risk ones), along with gilts, cash deposits, and perhaps convertibles or the income shares of split capital investment trusts.
If you are younger, and in a solid financial position, you may decide to take an aggressive approach -- but only if you're blessed with a sanguine disposition and won't suffer sleepless nights over share prices. If portfolio, alongside your more pedestrian in vestments. Once you have decided on your investment aims, you can then decide where to put your money. The golden rule here is spread your risk -- if you put all of your money into Periwigs International, you're setting yourself up as a hostage to fortune.
*'Periwigs' is the name of a fictitious company.
INVESTOR'S CHRONICLE, March 23 1990
New words and expressions 生词和短语
portfolio
n. 投资组合
tipster
n. （以提供证券投机等内部消息为主的）情报贩子
Las Vegas
n. 拉斯韦加斯
fritter
v. 挥霍，浪费
reputable
n. 享有声望的
broker
n. 经纪人
finance
n. 资金，财源
mortgage
n. 抵押贷款
pension
n. 养老金
priority
n. 优先权
gilt
n. 金边证券（高度可靠的证券）
convertible
n. 可换证券
sanguine
alongside
prep. 在……旁边，和……一起
pedestrian
我们周围不乏情报贩子，向人们提供迅速发财致富的机遇。但是，如果你是一个认真的私人投资者，就把拉斯韦加斯的心态留给那些有钱可供挥霍的人。认真的投资者需要一份正规的投资组合表 -- 一种计划很周密的投资选择，包括你的投资结构和明确的目标。但是, 一个股票市场的新手又如何能做到这一点呢？
如果你去向5位有威望的股票经纪人咨询，询问你应该如何使用你的资金，你可能得到5种不同的答复，即便你提供了有关于你的年龄、家庭、财源和你想从投资中获得好处的信息。这是个道德问题吗？没有一种完全“正确”的方法来排列这种投资组合，然而，却毫无疑问地有几种错误的方法。可以相信5位经纪人中不会有人建议你把全部（或一部份）资金投入佩里威格斯公司。
那么你该怎么做呢？我们假定你已把基本情况弄清楚了，如抵押贷款、养老金、保险金和动用现金储备的机会。然后，你一定要建立起自己的目标。这里一方面是个所处的环境，另一方面是个心理学的问题。
比如说，如果你年纪较大，你从重大投资损失中恢复过来的时间就较少，你就很希望能够提高你的养老金收入。因此，你的首要任务就是保护你的资金和引发额外的收入。在这种情况下，你大概想制定一份包括某些股份（但不是风险很大的股份）的投资组合，同时还有高度可靠的证券、现金储蓄，可能还有可换证券，或分割资本投资信托公司的所得股。
如果你年轻一些，并且经济状况可靠，你可能会采取一种积极进取的方式 -- 你必须性格开朗，不会因股票价格的浮动而夜不能眠。如果你觉得你的情况是这样的话，你可在投资组合中包括几项有令人陶醉的增值前景的增长股，和其他比较平淡的投资项目放在一起。一旦你的投资组合中包括几项有令人陶醉的增值前景的增长股，和其他比较平淡的投资项目放在一起。一旦你的投资目标确立以后，你就可以决定你的钱投向何处。这里的指导原则是：分散你的投资风险。如果你把所有资金投入佩里威格斯国际公司，你就把自己当成了命运的人质。
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2018-09-26 10:39:04
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https://www.codecogs.com/library/engineering/fluid_mechanics/pipes/mouthpiece/convergent-mouthpiece.php
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• https://me.yahoo.com
# Convergent Mouthpiece
Discharge and Pressure in a Convergent Mouthpiece
## Discharge Through A Convergent Mouthpiece
Generally a jet of liquid gets contracted at the entrance of a mouthpiece. There is always some loss of head due to this contraction of the jet. To counteract the loss of head, due to contraction of the jet up to vena contract, the mouthpiece is given the same slope as that of the jet of liquid as shown in fig-1.
In such a mouthpiece, there will be no loss of head due to expansions. If such a mouthpiece terminates at the vena contracta of the jet, then the mouthpiece is called convergent mouthpiece.
Let,
• $\inline&space;H$ = Height of the liquid above the mouthpiece
• $\inline&space;a$ = Area of the orifice at point B, and
• $\inline&space;v$ = Velocity of the jet
Applying Bernoulli's equation to points A and B,
$H&space;=&space;\frac{v^2}{2g}$
$\Rightarrow&space;v&space;=&space;\sqrt&space;{2gH}$
$\therefore&space;Actual\;Discharge,\;Q&space;=&space;Area\;of\;the\;orifice&space;\times&space;Actual\;velocity$
$\Rightarrow&space;Q&space;=&space;a\sqrt{2gH}$
We know that the actual discharge,
$Q&space;=&space;Coefficient\;of\;discharge&space;\times&space;Area\;of\;orifice&space;\times&space;Theoretical\;velocity$
$\Rightarrow&space;Q&space;=&space;C_d.a\sqrt&space;{2gH}$
Equating equation (1) and (2)
$a\sqrt&space;{2gH}&space;=&space;C_d.a\sqrt&space;{2gH}$
$\inline&space;\therefore$ Coefficient of discharge,$\inline&space;C_d$ = 1
and discharge, $\inline&space;Q&space;=&space;a\sqrt&space;{2gH}$
Example:
[metric]
##### Example - Discharge through a Convergent Mouthpiece
Problem
A convergent mouthpiece is discharging water under a constant head of 5m. Find the discharge, if diameter of the mouthpiece is 75 mm.
Workings
Given,
• $\inline&space;H$ = 5m
• $\inline&space;d$ = 75mm = 0.075m
The area of the mouthpiece,
$a&space;=&space;\frac{\pi}{4}&space;\times&space;(d)^2&space;=&space;\frac{\pi}{4}&space;\times&space;(0.075)^2&space;=&space;4.418\times&space;10^{-3}\;m^2$
and discharge through the mouthpiece,
$Q&space;=&space;1\times&space;a\sqrt&space;{2gH}$
$\Rightarrow&space;1\times&space;(4.418\times&space;10^{-3})\times&space;\sqrt&space;{2\times&space;9.81\times&space;5}&space;m^3/s$
$\Rightarrow&space;Q&space;=&space;0.0438\;m^3/s&space;=&space;43.8\;liters/s$
Solution
Discharge through the mouthpiece = 43.8 liters/s
## Pressure In A Convergent Mouthpiece
Consider a vessel, open to atmosphere at its top, having an orifice fitted with a convergent mouthpiece as shown in fig-2. We know that the slope of the mouthpiece is the same as that of the jet up to vena contracta.
Let,
• $\inline&space;H_a$ = Atmospheric pressure head
• $\inline&space;H$ = Height of liquid above the the mouthpiece
• $\inline&space;H_c$ = Absolute pressure head at vena contracta, and
• $\inline&space;v$ = Velocity of the jet
Applying Bernoulli's Equation to points A and C,
$H_a&space;+&space;H&space;=&space;H_c&space;+&space;\frac{v^2}{2g}$
$\Rightarrow&space;H_c&space;=&space;H_a&space;+&space;H&space;-&space;\frac{v^2}{2g}$
If there is no loss of head, then
$H&space;=&space;\frac{v^2}{2g}$
Now substituting this value of H in equation (3)
$H_c&space;=&space;H_a&space;+&space;H&space;-&space;H&space;=&space;H_a$
This shows that the absolute pressure head at the vena contracta is the same as that of the atmosphere. But in actual practice, the flow is no longer a steady one.
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2022-11-29 15:26:43
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http://www.passionforpuzzles.com/puzzles/rubiks-magic-rings-extended-version
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# Rubik’s magic rings (extended version)
/Rubik’s magic rings (extended version)
## Rubik’s magic rings (extended version)
By | 2012-08-03T12:56:20+00:00 July 27th, 2012|0 Comments
Name: Rubik's magic rings (extended version)
Manufacturer: Matchbox
Where to buy: Rubik’s magic rings (extended version) at Puzzle Master Inc.
Object: This is an extended version of Rubik's magic with 12 tiles. There are two separate puzzles for this folding puzzle. Fold all tiles until you have got five separate magic with as I call it rainbow colors. The other puzzle is to create five magic with rainbow colors but than overlapping each other like the Olympic Games Symbol.
### About the Author: Passion for Puzzles
A Person with Love and Passion for Puzzles.
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2018-06-24 13:13:17
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http://www.goodmath.org/blog/2014/03/13/squishy-equivalence-with-homotopy/
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# Squishy Equivalence with Homotopy
In topology, we always talk about the idea of continuous deformation. For example, we say that two spaces are equivalent if you can squish one into the other – if your space was made of clay, you could reshape it into the other just by squishing and molding, without ever tearing or gluing edges.
That’s a really nice intuition. But it’s a very informal intuition. And it suffers from the usual problem with informal intuition: it’s imprecise. There’s a reason why math is formal: because it needs to be! Intuition is great, as far as it goes, but if you really want to be able to understand what a concept means, you need to go beyond just intuition. That’s what math is all about!
We did already talk about what topological equivalence really is, using homeomorphism. But homeomorphism is not the easiest idea, and it’s really hard to see just how it connects back to the idea of continuous deformation.
What we’re going to do in this post is look at a related concept, called homotopy. Homotopy captures the idea of continuous deformation in a formal way, and using it, we can define a form of homotopic equivalence. It’s not quite equivalent to homeomorphism: if two spaces are homeomorphic, they’re always homotopy equivalent; but there are homotopy equivalent spaces that aren’t homeomorphic.
How can we capture the idea of continuous transformation? We’ll start by looking at it in functions: suppose I’ve got two functions, $f$ and $g$. Both $f$ and $g$ map from points in a topological space $A$ to a topological space $B$. What does it mean to say that the function $f$ can be continuously transformed to $g$?
We can do it using a really neat trick. We’ll take the unit interval space – the topological space using the difference metric over the interval from 0 to 1. Call it $U = [0, 1]$.
$f$ can be continuously deformed into $g$ if, and only if, there is a continuous function $t: A \times U \rightarrow B$, where $\forall a \in A: t(a, 0) = f(a) \land t(a, 1) = g(a)$.
If that’s true, then we say $t$ is a homotopy between $f$ and $g$, and that $f$ and $g$ are homotopic.
That’s just the first step. Homotopy, the way we just defined it, doesn’t say anything about topological spaces. We’ve got two spaces, but we’re not looking at how to transform one space into the other; we’re just looking at functions that map between the spaces. Homotopy says when two functions between two spaces are loosely equivalent, because one can be continuously deformed into the other.
To get from there to the idea of transformability of spaces, we need to think about what we’re trying to say. We want to say that a space $A$ can be transformed into a space $B$B. What does that really mean?
One way to say it would be that if I’ve got $A$, I can mush it into a shape $B$, and then much it back to $A$, without ever tearing or gluing anything. Putting that in terms of functions instead of squishies, that means that there’s a continous function $f$ from $A$ to $B$, and then a continous function $g$ back from $B$ to $A$. It’s not enough just to have that pair of functions: if you apply $f$ to map $A$ to $B$, and then apply $g$ to map back, you need to get back something that’s indistinguishable from what you started with.
Formally, if $A$ and $B$ are topological spaces, and $f: A \rightarrow B$ and $g: B \rightarrow A$ are continuous functions, then the spaces $A$ and $B$ are homotopically equivalent – equivalent over squishing and remolding, but not tearing or gluing – if $f \circ g$ is homotopic with the id function on $A$, and $g \circ f$ is homotopic with the id function on $B$.
That captures exactly the notion of continuous transformation that we tried to get with the intuition at the start. Only now it’s complete and precise – we’ve gotten rid of the fuzziness of intuition.
## 7 thoughts on “Squishy Equivalence with Homotopy”
1. Filip Nikšić
The notion of homotopy is connected to one of the hottest topics these days—homotopy type theory (HoTT)—where types are interpreted as spaces, and equality is interpreted as homotopy. How about touching upon HoTT in one of your future posts?
1. markcc Post author
To be honest, I don’t know anything about it. I’ll try to find some time to read up – any particularly good refs you can point me at?
2. John Armstrong
This is a little misleading. The notion of “homotopy” they really care about in HoTT is a categorical generalization of topological homotopy. Specifically, it’s working in weak 2- (or n-)categories, where a homotopy-equivalence between objects A and B is a pair of 1-morphisms f: A -> B and g: B -> A and 2-isomorphisms between the two compositions and the identity 1-morphisms.
This is specifically applied to a category in which objects are types, 1-morphisms are functions, and 2-morphisms are.. well.. to be honest I’m not sure offhand what with holding down a real job and another full-time hobby already.
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2023-03-21 13:51:47
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http://math.stackexchange.com/questions/260391/central-limit-theorem-confusion
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# Central limit theorem confusion
If a bunch of random variables $X_i$ are independently and identically distributed with an exponential distribution, their sum apparently follows a Gamma distribution.
But doesn't the central limit theorem imply that (for $X_i$ of any distribution with mean zero and variance $\sigma^2$), the sum $\sum_{i=1}^n X_i$ will become approximately normally distributed $~N(0,n\sigma^2)$ for large enough $n$ ?
Obviously I am missing something basic, but what's going on? How can the sum of i.i.d. exponential random variables have a Gamma distribution, but also be converging to normality?
-
There are several confusions here (I was also very confused when I started learning about that topic :-).)
• Exponential random variables have a non zero mean (and are positive). The quantity you should be looking at, which asymptotically converges in distribution to a normal variable is $$\sqrt{n} \left( \frac{\sum_{i = 1}^n X_i}{n} - \mu \right)$$ The $\sqrt{n}$ was essential here, otherwise the distribution of the average will converge to a point mass at $\mu$. That quantity will converge to $N(0,\sigma^2)$. Both $\mu$ and $\sigma$ will be determined by the parameter of the exponential distribution.
• The central limit theorem is asymptotic. The quantity $\sqrt{n} \left( \frac{\sum_{i = 1}^n X_i}{n} - \mu \right)$ will have a distribution. Let's call it $F_n$. (it is essential to remember that it depends on $n$). $F_n$ in general is not a normal distribution $N(0,\sigma^2)$. The central limit theorem tells us that that distribution gets in a certain sense closer and closer to $N(0,\sigma^2)$ as $n \to \infty$.
-
Yes I was mistaken in talking about a mean of zero, which is impossible for exponentials (actually I was originally motivated to ask this question because I wanted to sum Laplaces, but thinking about exponentials was the first step). But I'm confused by the $\sqrt(n)$ being essential there. That expression is giving a distribution for the sample average. Doesn't the CLT also give you an approximate distribution for the sample sum? Is it wrong to say that the sum of random variables with variance $\sigma^2$ will converge to a normal distribution with variance $n \sigma^2$? – s4027340 Dec 17 '12 at 2:03
@s4027340 The problem with saying that the sum of random variables will converge to a Normal distribution with variance $n\sigma^2$ as $n \rightarrow \infty$ is that $n\sigma^2 \rightarrow \infty$ too, and it doesn't help much to talk about a Normal distribution with infinite variance! It is absolutely correct to say that for any (large-ish) finite $n$, the distribution of the sum is approximately Normal with variance $n\sigma^2$, like you said--it just doesn't make much sense in the limit. – Jonathan Christensen Dec 17 '12 at 2:08
Ah, of course! That makes sense. – s4027340 Dec 17 '12 at 2:09
Good question! The Gamma distribution itself converges to a Normal distribution--exactly the Normal distribution that the Central Limit Theorem says the sum of the Exponential random variables converges to.
Of course, for any finite $n$ the distribution of the sum of Exponentials (the Gamma distribution) is not a normal distribution, since it's bounded below by zero, but as $n$ gets larger it gets closer and closer to a Normal distribution.
Here's a page that discusses the approximation, with some graphs that show how the Gamma distribution looks like a Normal when the first parameter (= the number of Exponential random variables you are summing up) gets large.
-
Is the difference between gamma and normal basically due to the negative part on the normal's left tail? – s4027340 Dec 17 '12 at 1:59
The shape of the Gamma will never be exactly a Normal distribution, even if you ignore the left-tail problem. But the CDF will get closer and closer to a Normal CDF. – Jonathan Christensen Dec 17 '12 at 2:06
Thanks for the link! – s4027340 Dec 17 '12 at 2:06
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2015-08-28 00:22:57
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https://tex.stackexchange.com/questions/474553/wrong-page-numbers-listed-in-toc-latex
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Wrong page numbers listed in ToC (LaTeX) [closed]
I am struggling with a problem with ToC page numbering visible in a document. I've tried several possible solution, including \phantomsection, \clearcoublepage, and other similar. Nothing helps. What I see is the ToC page numbers are lagging behind real page numbers and increasingly (1 page in first 40 pages of the document, over 10 pages in 360+ pages of the document). I'm helpless. Below I post the working code from my file. It is messy, but it used to work with a similar document a few year ago. I most probably have messed up something -_-
What I tried:
1. Compiling multiple times (3 times in each run). Does not help.
2. Removing all figures and tables from the text. Does not help.
3. Removing all packages that are not necessary. Does not help.
4. Trying all the hints from the responses below. Did not help.
Problem solved. Required 4 compilations for an unknown reason.
\documentclass{book}
\usepackage{polski}
\usepackage[cp1250]{inputenc}
\usepackage[dvipsnames,usenames]{color}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage[round,comma,sort]{natbib}
\usepackage{pdflscape}
\usepackage{rotating}
\usepackage{afterpage}
\usepackage{multirow}
\usepackage{tablefootnote}
\usepackage{threeparttable}
\usepackage{array}
\usepackage{flafter}
\begin{document}
\frontmatter
\title{
\Large{\textbf{Comprehensive Title}\\
\vspace{20mm}}
}
\author{Probably myself}
\date{Sometimes around today}
\maketitle
\frontmatter
\tableofcontents
\input{skroty.tex}
\mainmatter
\input{wstep.tex}
\begin{appendices}
\input{dodatek_A.tex}
\end{appendices}
\cleardoublepage
\listoffigures
\cleardoublepage
\listoftables
\cleardoublepage
\bibliography{aaa}
\bibliographystyle{plainnat}
\end{document}
closed as off-topic by Mensch, Raaja, dexteritas, schtandard, Stefan PinnowAug 5 at 9:31
• This question does not fall within the scope of TeX, LaTeX or related typesetting systems as defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.
• I didn't know. Thanks for editing :) – pjantos Feb 12 at 17:33
• I have conversed the input file into book.cls. It should compile (at least it does for me). Doesn't look nice, but works. The problem with page numbering remains. I've checked after 50, 100 and 150 pages. ToC lags behind and the number of pages it stays behind increases. (edit) To answer your second question - I have compiled the document three times in each run. Does not affect the page numbering, alas. – pjantos Feb 12 at 18:06
• t clear the page, then add the contentsline command, then insert the list of tables (or whatever). – Johannes_B Feb 12 at 19:02
• \usepackage{tocbibind} should solve your problems instead of manually adding those entries with \addcontentsline etc.... – user31729 Feb 12 at 19:26
• Hi, I have tried both changing the order of the commands and using tocbibind. The former has brought no changes, the latter, whilst more elegant, has not changed a thing, either. I tried to remove all packages that are not used or not really needed. Unfortunately the problem remains. Turning the code into something more workable, e.g. using package ipsum brought no convincing result. I get an impression that the TeX does not count the "space used" properly, thus, making the page counter lag behind. Not sure if it happens due to the figures inserted? – pjantos Feb 13 at 10:50
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2019-08-24 09:36:57
|
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http://mathinsight.org/applet/double_integral_riemann_sum
|
# Math Insight
### Applet: Double integral Riemann sum
The volume of the small boxes illustrates a Riemann sum approximating the volume under the graph of $z=f(x,y)$, shown as a transparent surface. The surface is the graph of the function $f(x,y)=\cos^2 x + \sin^2 y$. The volume is computed over the region $D$ defined by $0 \le x \le 2$ and $0 \le y \le 1$. Therefore, the actual volume is the double integral $\iint_D f\,dA$. The volume of the boxes is $$\sum_{i,j} f(x_{i},y_{j})\Delta x \Delta y$$ where $x_i$ is the midpoint of the $i$th interval along the $x$-axis and $y_j$ is the midpoint of the $j$th interval along the $y$-axis. Drag the points on the sliders to change $\Delta x$ and $\Delta y$ as well as the number of intervals along each axis. As $\Delta x$ and $\Delta y$ approach zero, the volume of the boxes (labeled as “estimate”) approaches the actual volume of the integral $\iint_D f\,dA$.
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2017-06-28 08:59:19
|
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https://www.answers.com/Q/What_is_the_area_of_a_square_that_has_5_meters_width_and_12_meters_length
|
Math and Arithmetic
Algebra
Geometry
# What is the area of a square that has 5 meters width and 12 meters length?
###### Wiki User
5 x 12 is not a square, but its area is 60 square meters.
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## Related Questions
### What is the formula of square meters?
Multiply the length in meters by the widthin meters to get the area in square meters.
### How do you find the floor area of a room?
If the room is rectangular - the usual case - multiply the length times the width. If length and width are in meters, the area will be in square meters; if length and width are in feet, the area will be in square feet, etc.
### If the length of a rectangle is six times the width and area is 37 square meters what is the length and width.?
Length = 6* widthArea = 37Area = length * widthArea = 6* width * width37 = 6w^2w = square root of 37/6W = square root(37 / 6) = 2.4832774 meters
### What is the area of 60 meters?
60 meters have an area of 0 square meters.Meters are a unit of length and have zero (0) width;area = length x width= 60 meters x 0 meters= 0 square meters.
### What is the area of a rectangle that is 9 meters long and 8 meters wide?
The area of a rectangle is simply the length times the width. If the length and width are in meters, the area, of course, will be in square meters.
### The area of a rectangle is 117 square meters. The width is 9 meters.What is the length of the rectangle?
If the area is 117 square meters and the width is 9 meters we can find the length by dividing: 117 / 9 = 13 The length is 13 meters
### How do you measure a room in sq meters?
Measure the length and width of the room in meters. Multiply the length x width to get the area in square meters.
### How big is 10000 square meters?
As a square area it is 100 meters in width and 100 meters in length. Is that big?
### How do you work out the square meter of a swimming pool?
Its length in meters times its width in meters is its square area in meters.
### How do you convert length and width to square meter?
Make sure both length and width are measured in meters and multiply. The unit with be the area in square meters. The length and width alone can't be square measurements because they are one dimentional
### A rectangle has an area of 31.2 square meters what is the width of the rectangle if the length is 6 meters?
area of a rectangle = length * width. Rearranging, we have width = area / length. Therefore, the width of the rectangle = 31.2 [m2] / 6 [m] = 5.2 [m] ========================
### How big is 1100 square meter?
As a square the area of 1100 square meters is 33.166 meters in length and 33.166 meters in width.
### What is the area of a rectangle with a length 21m and width 17m?
The area of a rectangle is simply length times width. The area in this case will have units of square meters.
### What is the length and width of 30 acres?
One acre equals:0.0015625 square miles,4,840 square yards,43,560 square feet orabout 4,047 square metres (0.405 hectares)So, an acre is a unit of area. To know the length and width, the heometry sholud be known.For example it could be:a rectangle of length 1000 meters and width 4.047 meters, ora rectangle of length 500 meters and width 8.094 metersa square of length = width = 63.616 meters
### What is 488.33 square meters into meters?
There is no direct conversion between square meters and meters as they measure different things:square meters are a measure of area and have two dimensionsmeters are a measure of length and has only one dimensionTo convert requires losing a dimension, which requires a division by a length. For example, if the area is rectangular, then dividing its area (in square meters) by its width (in meters) will give its length (in meters).If the shape is regular, for example a square then the length and width are the same, then so finding a square root will suffice.Square metere
### What is the length of a rectangle with an area of 28.08 square meters if the width is 3.6 meters?
area=28.08 breadth[width]=3.6 length= a divided by b =28.08 divided by 3.6 = ................
### How big is 5 million square meters?
A very big area. That is a square of 2236 meters length and 2236 meters width.
### What is the length of a rectangle whose area is 72 square meters and whose width is 6 meters?
The length of a rectangle whose area is 72 square meters and whose width is 6 meters, would be 12. Note that 12 x 6 = 72.
### How do you find the length of rectangle or square if the area and width are known?
For a rectangle or square, Area = Length * Width So Length = Area / Width.
### How do you convert a rectangular space into square meters?
Using a metric tapemeasure,multiply the length of your rectangle by the width.
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2021-02-25 22:57:15
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https://math.stackexchange.com/questions/1980231/what-is-relationship-between-distributional-and-fourier-series-frameworks-for-pr
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# What is Relationship Between Distributional and Fourier Series Frameworks for Prime Counting Functions?
I've defined three general methods for derivation of formulas for prime counting functions where each prime counting function is represented by an infinite series of Fourier series, and illustrated application of the first method to six different prime counting functions on the following website.
Illustration of Fourier Series for Prime Counting Functions
In the distributional framework for prime counting functions the first-order derivatives are represented by Dirac delta distributions. In the case of $\psi'(x)$, there is a Dirac delta distribution at each prime-power value of $x$ with weight $Log(p)$ where $x$ is of the form $x=p^n$. Note the real portion of the Fourier transform of a Dirac delta function is a Cosine term.
(1) $\quad \operatorname{FourierTransform}(\delta(x-a),x,y)=e^{-2\,i\,\pi\,a\,y}=\cos(2\,\pi\,a\,y)-i\,\sin(2\,\pi\,a\,y)\,,\quad a\in\mathbb{R}$
In the Fourier series framework for prime counting functions, the first-order derivatives are represented by infinite series of Fourier series which converge to the Dirac delta distributions in the distributional framework. These Fourier series consist of Cosine terms, and note the Fourier transform of a Cosine function is a pair of Dirac delta distributions.
(2) $\quad \operatorname{FourierTransform}(\cos(2\,\pi\,b\,x),x,y)=\dfrac{\delta(b-y)}{2}+\dfrac{\delta(b+y)}{2}$
The Fourier transforms in (1) and (2) above both assume the Fourier parameters $\{0,\,-2\,\pi\}$.
Question 1: What is the relationship between the Cosine terms in the distributional framework and the Dirac delta distributions in the Fourier series framework? For example, do the Cosine terms in the distributional framework converge to the Dirac delta distributions in the Fourier series framework, analogous to the way the Cosine terms in the Fourier series framework converge to the Dirac delta distributions in the distributional framework?
Question 2: If the analogous relationship in question 2 is valid, is this convergence in any way sensitive to the Fourier parameters used for the two Fourier transforms? For example, will the convergence only apply when using the same set or a specific set of Fourier parameters for both Fourier transforms? Or will the convergence perhaps be faster if the same Fourier parameters are used for both Fourier transforms versus using different Fourier parameters for the two Fourier transforms?
1/1/2018 Update: I believe the discrepancies between the Fourier transforms of the distributional and Fourier series representations of prime-counting functions result from the idealization of the Fourier transform of $sin$ and $cos$ functions as Dirac delta ($\delta$) functions. Please see the answer I posted below which I believe provides a fair amount of insight into the theory and value of Fourier series representations of non-periodic functions. Happy New Year!
3/26/2018 Update:
The following link defines and illustrates a general method for derivation of a Fourier series representation for $f(x)=\sum\limits_{n=1}^x a(n)$ related to the Dirichlet series $F(s)=\sum\limits_{n=1}^\infty\frac{a(n)}{n^s}$.
Derivation of Fourier Series Representation for $f(x)=\sum\limits_{n=1}^x a(n)$
• Please don't vandalize your question, Steve. – Gerry Myerson Oct 30 '16 at 5:44
• You cannot delete your question because it has received two (upvoted) answers. Other people have spent effort on the question, and their effort has been deemed useful by users. It would not be fair to them to let the question poser delete the question single-handedly. As for the chat, chat messages can - except by moderators - only be deleted for a short time (a few minutes, I don't remember the exact limit). I've deleted the link to the chat room, that's about as good as deleting the whole conversation. – Daniel Fischer Oct 30 '16 at 12:30
• @DanielFischer I didn't create my comments in chat, they were moved to chat, but thanks for at least deleting the link to chat. The answers below were both in response to my original pair of questions, and don't make sense in the context of the additional questions which I've since added, so I'll edit my question back to my original pair of questions. – Steven Clark Oct 30 '16 at 15:59
Your question means nothing. Work on $$\text{I}\Pi(x) = \sum_{k=-\infty}^\infty \delta(x-k) = 1+2 \sum_{n=1}^\infty \cos(2\pi n x)$$ where the Fourier series on the right converges only is in the sense of distributions, that is, for every $\varphi \in C_c^\infty$ with (*) compact support $[a,b]$ : $$\langle \text{I}\Pi, \varphi \rangle = \int_{-\infty}^\infty \text{I}\Pi(x) \varphi(x) \, dx = \sum_{k \in \mathbb{Z} \cap [a,b]} \varphi(k)$$ $$=\lim_{N \to \infty} \langle 1+2 \sum_{n=1}^N \cos(2\pi n x), \varphi \rangle = \lim_{N \to \infty} \int_{-\infty}^\infty (1+2 \sum_{n=1}^N \cos(2\pi n x)) \varphi(x) \, dx$$
So what I mean is : there is no Fourier series for the Dirac delta, there is only a Fourier series for the Dirac comb $\text{I}\Pi(x)$.
And read a course on : the Fourier series and the Fourier transform, on the distributions, on some complex analysis and the Laplace/Mellin transform.
(*) Since $\text{I}\Pi(x)$ is tempered distribution of order $1$, you can extend $\langle \text{I}\Pi,\varphi \rangle$ to any $\varphi(x)$ continuous (at $x \in\mathbb{Z}$) and with compact support, or decreasing fast enough at $x \to \infty$.
For example, it is perfectly true that $\langle \text{I}\Pi(x) ,x^{-s}\Lambda(\lfloor x+1/2 \rfloor) \rangle = \sum_{n=1}^\infty n^{-s}\Lambda(n) = \frac{-\zeta'(s)}{\zeta(s)}$ for $Re(s) > 1$, but it doesn't mean that $$\frac{-\zeta'(s)}{\zeta(s)} = \lim_{N\to \infty} \int_{1/2}^\infty x^{-s} \Lambda(\lfloor x+1/2 \rfloor)(1+2\sum_{n=1}^N \cos(2\pi n x)) \, dx$$ and this is all the point of the theory of distributions (and the theory of the Riemann zeta function) to study those kind of things.
• Arguing that my formulas for $\psi[x]$, $\psi'[x]$, $UnitStep[x-1]$, and $UnitStep'[x-1]=\delta[x-1]$ can not converge because a single Fourier series does not converge is like arguing that von Mangoldt's formula can not converge because a single zeta zero contribution does not converge. – Steven Clark Jan 31 '17 at 4:12
• Would you also argue that von Mangoldt's formula for $\psi[x]$ does not converge to a set of distributions at prime powers, and it's first-order derivative does not converge (up to a very simple term) to a set of Dirac delta functions at prime powers? The corresponding convergences of my formulas for $\psi[x]$ and it's first-order derivative are just as valid, and likewise the convergence of my formula for $UnitStep[x-1]$ to a single distribution at $x=1$ and the convergence of it's first-order derivative to the single Dirac delta function $\delta(x-1)$ are just as valid. – Steven Clark Jan 31 '17 at 15:46
• @SteveC. When I say "read some courses" I mean proving many theorems. You can't understand what is in the books about $\zeta(s)$ without proving first some theorems : about the Fourier series, the Fourier/Laplace/Mellin transform, the holomorphic functions. Did you try reading a course on the (convergence of) Fourier series ? There are many difficult problems in this field, and it teaches you a fundamental fact in analysis : many obvious formulas are completely false, because it doesn't converge as we expected. – reuns Feb 1 '17 at 0:05
• If you accept that the Fourier series for the Dirac comb converges to the Dirac comb, then it is but a small additional step to accept that my formulas for the prime counting functions converge to the prime counting functions. – Steven Clark Feb 12 '17 at 19:35
• Riemann's formula for $J[x]$ and von Mangoldt's formula for $\psi[x]$ are conditionally convergent, and likewise my formulas for prime counting functions are conditionally convergent. The conditional convergence of my formulas seems fairly elementary to me, and it seems very unlikely to me that I'm the first one ever to investigate the conditional convergence requirements for sums of Fourier series. Was this topic not covered in any of the books you've read or courses you've taken in Fourier analysis? – Steven Clark Feb 12 '17 at 19:35
Indeed, this is not an answer, except to some degree to the meta-question aspects: apart from the literal difficulties in terminology, etc, as others have raised, the apparent question implicitly assumes a number of things that are not entirely wrong, but really are partly wrong. Of course, this degrades the sense of the sequel.
In particular, it is unwise to apparently distinguish "conventional" X from the supposedly novel version of X, when, in fact, the "conventional" one is factually misrepresented, and at the same time the "novel" thing is standard, too. It'd be a bit analogous to saying that, although the sun has not shone in the past, new technology has made the sun shine ... and will clean your carpets, too. I realize this is parody, but it is not entirely different from the unfortunate dislocated sense of the "question". Perhaps understandable in some ways, but not good to be so aggressive on a basis of minimal information.
• Continuing some of @user1952009's indications... your questions can perhaps be given mathematical sense in various possible ways, but a fundamental obstacle is determining exactly what you mean by what you say. E.g., in your comment here, what does "evaluation parameters can be chosen..." mean? I can't guess it. Also, probably you didn't mean that $\delta_{1}$ is a "sum of cosine terms", if the latter create an even (generalized) function, since $\delta_1$ is not even. But, sure, it is possible to take Fourier transforms of tempered distributions... [cont'd] – paul garrett Oct 28 '16 at 22:02
• [cont'd] ... But, indeed, non-periodic functions simply do not have "Fourier series", since they in no way descend to the circle. But maybe that's not what you really intend... By the way, a certain version of what you may be getting after would be Guinand's version of (von Mangoldt's version of) Riemann's so-called explicit formula. (Also considered by A. Weil a few years after Guinand.) I think that is the number-theoretic content of this situation. Still, yes, it is true that there is some motivation to look at "modern analysis" here... and elsewhere... which is not well documented. – paul garrett Oct 28 '16 at 22:05
• @SteveC., a problem that I have is the "derived form a sieve which recovers..." An infinite sum of Fourier series is not necessarily a problem. Sawtooth functions are fine. But this is just delaying "paying the piper", to my mind. E.g., convergence in some topology? – paul garrett Oct 28 '16 at 23:44
I realize this answer is rather lengthy and contains a considerable number of formulas, but I think a significant amount of background information is necessary to understand my answer below as the topic of Fourier series representations of prime-counting functions and functions such as $\theta(x-1)$, $\delta(x-1)$, and $\delta'(x-1)$ seems to be unfamiliar territory for most everyone but myself. Also, I think the Fourier series representations of $\theta(x-1)$, $\delta(x-1)$, and $\delta'(x-1)$ deserve some elaboration for several reasons. First, these Fourier series representations can be used with various convolution integrals to derive new formulas for a variety of functions providing new insights into functions and their relationships. Second, these Fourier series representations are closely related to the Riemann zeta function $\zeta(s)$ which is illustrated by their Mellin transforms and various other derived formulas. Finally, the Fourier series representations of $\theta(x-1)$, $\delta(x-1)$, and $\delta'(x-1)$ can be generalized to representations of $\theta(x-a)$, $\delta(x-a)$, and $\delta'(x-a)$ which can in turn be used to derive Fourier series representations of prime-counting functions and their first and second order-derivatives.
Quite some time ago I noticed what appeared to be discrepancies between the Fourier transforms of the distributional and Fourier series representations of prime-counting functions which was the motivation for this question. I was initially trying to analyze these discrepancies in the context of the Fourier series representations of the second Chebyshev function $\psi(x)$ and it's first and second-order derivatives, but I decided to shift my focus to the considerably simpler context of the Fourier series representations of $U(x)$ and it's first and second-order derivatives defined below where $\theta(x)$ is the Heaviside step function (also referred to as the Unit step function) and $\delta(x)$ is the Dirac delta function.
(1) $\quad U(x)=-1+\theta(x+1)+\theta(x-1)$
(2) $\quad U'(x)=\delta(x+1)+\delta(x-1)$
(3) $\quad U''(x)=\delta'(x+1)+\delta'(x-1)$
The Fourier series representation of $U(x)$ is derived as follows.
(4) $\quad U(x)=\sum\limits_{n=1}^\infty\mu(n)\,Floor[\frac{x}{n}]$
(5) $\quad U(x)=\sum\limits_{n=1}^\infty\mu(n)\left(\frac{x}{n}-SawtoothWave(\frac{x}{n})\right)$
(6) $\quad U(x)=\sum\limits_{n=1}^\infty\mu(n)\,\left(\frac{x}{n}-\left(\frac{1}{2}-\frac{1}{\pi}\sum\limits_{k=1}^\infty\frac{\sin\left(\frac{2\,\pi\,k\,x}{n}\right)}{k}\right)\right)$
When evaluated at finite limits, the Fourier series representation defined in formula (6) above is conditionally convergent and must be evaluated as illustrated in formula (7) below. In formula (7) and all formulas derived from it below, all $SawtoothWave$ functions under evaluation must be evaluated to the same frequency versus the same harmonic which is one of several conditional convergence requirements. The parameter $f$ controls the evaluation frequency and is assumed to be a positive integer.
(7) $\quad U(x)=\sum\limits_{n=1}^N\mu(n)\,\left(\frac{x}{n}-\left(\frac{1}{2}-\frac{1}{\pi}\sum\limits_{k=1}^{f\,n}\frac{\sin\left(\frac{2\,\pi\,k\,x}{n}\right)}{k}\right)\right)$
Formula (7) above and all functions derived from it below converge under the conditions specified in (8) below where $\mathcal{M}(N)$ is the Mertens function. When $\mathcal{M}(N)$ evaluates to zero, $U(0)$ evaluates to zero since $U(0)=-\frac{1}{2}\sum\limits_{n=1}^N\mu(n)=-\frac{1}{2}\mathcal{M}(N)$ which is the net offset of all $SawtoothWave$ functions under evaluation.
(8) $\quad\mathcal{M}(N)=0\,\land\,N\to\infty\,\land\,f\to\infty$
Assuming the conditions stated in (8) above the $\frac{1}{2}$ term in formula (7) above can be ignored and formula (7) above can be simplified to (9) below.
(9) $\quad U(x)=\sum\limits_{n=1}^N\mu(n)\,\left(\frac{x}{n}+\frac{1}{\pi}\sum\limits_{k=1}^{f\,n}\frac{\sin\left(\frac{2\,\pi\,k\,x}{n}\right)}{k}\right)$
The Fourier series representation of $U'(x)$ is defined in (10) below.
(10) $\quad U'(x)=\sum\limits_{n=1}^N\frac{\mu(n)}{n}\,\left(1+2\sum\limits_{k=1}^{f\,n}\cos\left(\frac{2\,\pi\,k\,x}{n}\right)\right)$
Assuming the conditions stated in (8) above, since $\sum\limits_{n=1}^\infty\frac{\mu(n)}{n}=\frac{1}{\zeta(1)}=0$ formulas (9) and (10) above can be simplified to (11) and (12) below.
(11) $\quad U(x)=\frac{1}{\pi}\sum\limits_{n=1}^N\mu(n)\sum\limits_{k=1}^{f\,n}\frac{\sin\left(\frac{2\,\pi\,k\,x}{n}\right)}{k}$
(12) $\quad U'(x)=2\sum\limits_{n=1}^N\frac{\mu(n)}{n}\,\sum\limits_{k=1}^{f\,n}\cos\left(\frac{2\,\pi\,k\,x}{n}\right)$
The Fourier series representation of $U''(x)$ is defined in (13) below.
(13) $\quad U''(x)=-4\,\pi\sum\limits_{n=1}^N\frac{\mu(n)}{n^2}\sum\limits_{k=1}^{f\,n}k\,\sin\left(\frac{2\,\pi\,k\,x}{n}\right)$
The following three plots illustrate the Fourier series representations of $U(x)$, $U'(x)$, and $U''(x)$ defined in (9), (12), and (13) above where all three functions are evaluated at $N=101$ and $f=4$. Note $\mathcal{M}(101)=0$ consistent with (8) above. The red discrete portions of the three plots below illustrate the evaluation of the Fourier series representations of $U(x)$, $U'(x)$, and $U''(x)$ at integer values of $x$. Formula (9) is illustrated for $U(x)$ instead of formula (11) because formula (9) converges much better at modest evaluation limits than formula (11).
The following plot illustrates the Fourier series representation of $U(x)$ defined in (9) above in blue and the distributional representation of $U(x)$ defined in (1) above in orange. Under the conditions specified in (8) above, the Fourier series representation of $U(x)$ converges to the distributional representation of $U(x)$ consistent with the Heaviside step function half-maximum convention (i.e. converges to $-\frac{1}{2}$ at $x=-1$ and to $\frac{1}{2}$ at $x=1$).
Figure (1): Illustration of Formula (9) for $U(x)$
The following plot illustrates the Fourier series representation of $U'(x)$ defined in (12) above. The first-order derivative $U'(x)$ exhibits a strict convergence at integer values of $x$. $U'(x)$ defined in (12) above always evaluates exactly to $2\,f$ at $|x|=1$ and exactly to zero at $|x|\ne 1$ for $x\in \mathbb{Z}$ and $0<|x|\le N$. The convergence of $U'(x)$ to $0$ at $x=0$ requires $\mathcal{M}(N)=0$.
Figure (2): Illustration of Formula (12) for $U'(x)$
The following plot illustrates the Fourier series representation of $U''(x)$ defined in (13) above.
Figure (3): Illustration of Formula (13) for $U''(x)$
Formulas (9) and (11) above can be integrated in the right-half plane resulting in formulas (14) and (15) below. Note that under the conditions specified in (8) above $f(x+1)$ represents the linear function $x$ for $x\ge 0$. I believe one can continue to integrate in this manner to derive a formula for $x^m$ for $x\ge 0$ and $m\in\mathbb{Z}^+$.
(14) $\quad f(x)=\int_0^x U(t)\,dt=\frac{1}{2}\sum\limits_{n=1}^N\mu(n)\left(\frac{x^2}{n}+\frac{n}{\pi^2}\sum\limits_{k=1}^{f\,n}\frac{1-\cos\left(\frac{2\,\pi\,k\,x}{n}\right)}{k^2}\right)$
(15) $\quad f(x)=\int_0^x U(t)\,dt=\frac{1}{2\,\pi^2}\sum\limits_{n=1}^N\mu(n)\, n\sum\limits_{k=1}^{f\,n}\frac{1-\cos\left(\frac{2\,\pi\,k\,x}{n}\right)}{k^2}$
The Laplace transforms of the distributional representations of $U(x)$, $U'(x)$, and $U''(x)$ defined in (1), (2), and (3) above are as follows.
(16) $\quad\mathcal{L}_x[U(x)](y)=\frac{e^{-y}}{y}\,,\quad\Re(y)>0$
(17) $\quad\mathcal{L}_x[U'(x)](y)=e^{-y}$
(18) $\quad\mathcal{L}_x[U''(x)](y)=y\,e^{-y}$
The Laplace transforms of the Fourier series representations of $U(x)$, $U'(x)$, and $U''(x)$ defined in (11), (12), and (13) above are as follows. Under the conditions stated in (8) above, the Laplace transforms of the Fourier series representations defined below converge to the Laplace transforms of the distributional representations for $Re(y)>0$.
(19) $\quad\mathcal{L}_x[U(x)](y)=\frac{e^{-y}}{y}=2\sum\limits_{n=1}^N\mu(n)\,n\sum\limits_{k=1}^{f\,n}\frac{1}{4\pi^2\,k^2+n^2\,y^2}\,,\quad\Re(y)>0$
(20) $\quad\mathcal{L}_x[U'(x)](y)=e^{-y}=2\,y\sum\limits_{n=1}^N\mu(n)\,n\sum\limits_{k=1}^{f\,n}\frac{1}{4\pi^2\,k^2+n^2\,y^2}\,,\quad\Re(y)>0$
(21) $\quad\mathcal{L}_x[U''(x)](y)=y\,e^{-y}=-8\,\pi ^2\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\frac{k^2}{4\pi^2\,k^2+n^2\,y^2}\,,\quad\Re(y)>0$
The Laplace transforms defined in (19), (20), and (21) above are illustrated at the following link.
Laplace Transforms of $U[x]$, $U'[x]$, and $U''[x]$
The Laplace transforms of the Fourier series representations of $U(x)$, $U'(x)$, and $U''(x)$ defined in (11), (12), and (13) above can also be written as (22), (23), and (24) below which, under the conditions stated in (8) above, also converge to the Laplace transforms of the distributional representations for $Re(y)>0$.
(22) $\quad\mathcal{L}_x[U(x)](y)=\frac{e^{-y}}{y}=-\frac{8\,\pi ^2}{y^2}\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\frac{k^2}{4\pi^2\,k^2+n^2\,y^2}\,,\quad\Re(y)>0$
(23) $\quad\mathcal{L}_x[U'(x)](y)=e^{-y}=-\frac{8\,\pi ^2}{y}\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\frac{k^2}{4\pi^2\,k^2+n^2\,y^2}\,,\quad\Re(y)>0$
(24) $\quad\mathcal{L}_x[U''(x)](y)=y\,e^{-y}=2\,y^2\sum\limits_{n=1}^N\mu(n)\,n\sum\limits_{k=1}^{f\,n}\frac{1}{4\pi^2\,k^2+n^2\,y^2}\,,\quad\Re(y)>0$
The distributional representations of $U(x)$, $U'(x)$, and $U''(x)$ defined in (1), (2), and (3) above all have special relationships between their Fourier transforms and inverse Fourier transforms which are illustrated below where I believe the sign is related to whether each is an odd or even function. The Fourier transforms below and all subsequent Fourier transforms assume the Fourier parameters $\{0,\,-2\pi\}$.
(25) $\quad\mathcal{FT}_x[U(x)](z)=-\mathcal{FT}_x^{-1}[U(x)](z)=-\frac{i\,\cos(2\,\pi\,z)}{\pi\,z}$
(26) $\quad\mathcal{FT}_x[U'(x)](z)=\mathcal{FT}_x^{-1}[U'(x)](z)=2\,\cos(2\,\pi\,z)$
(27) $\quad\mathcal{FT}_x[U''(x)](z)=-\mathcal{FT}_x^{-1}[U''(x)](z)=4\,i\,\pi\,z\,\cos(2\,\pi\,z)$
The $sin$ and $cos$ terms associated with the Fourier series representations of $U(x)$, $U'(x)$, and $U''(x)$ also have special relationships between their Fourier transforms and inverse Fourier transforms which are illustrated below.
(28) $\quad\mathcal{FT}_x\left[\sin\left(\frac{2\,\pi\,k\,x)}{n}\right)\right](z)=-\mathcal{FT}_x^{-1}\left[\sin\left(\frac{2\,\pi\,k\,x)}{n}\right)\right](z)=\frac{1}{2}i\,\delta\left(\frac{k}{n}+z\right)-\frac{1}{2}i\,\delta\left(\frac{k}{n}-z\right)$
(29) $\quad\mathcal{FT}_x\left[\cos\left(\frac{2\,\pi\,k\,x)}{n}\right)\right](z)=\mathcal{FT}_x^{-1}\left[\cos\left(\frac{2\,\pi\,k\,x)}{n}\right)\right](z)=\frac{\delta \left(\frac{k}{n}+z\right)}{2}+\frac{\delta \left(\frac{k}{n}-z\right)}{2}$
Term-wise integration of the Fourier series representation of $U(x)$, $U'(x)$, and $U''(x)$ defined in (11), (12), and (13) above implies the following Fourier transforms for the Fourier series representation of each of these functions which are obviously inconsistent with the corresponding Fourier transforms of the distributional representation defined in (25), (26), and (27) above.
(30) $\quad\mathcal{FT}_x[U(x)](z)=\frac{i}{2\,\pi}\sum\limits_{n=1}^N\mu(n)\sum\limits_{k=1}^{f\,n}\frac{\delta\left(\frac{k}{n}+z\right)-\delta\left(\frac{k}{n}-z\right)}{k}$
(31) $\quad\mathcal{FT}_x[U'(x)](z)=\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\left(\delta\left(\frac{k}{n}+z\right)+\delta\left(\frac{k}{n}-z\right)\right)$
(32) $\quad\mathcal{FT}_x[U''(x)](z)=-2\,i\,\pi\sum\limits_{n=1}^N\frac{\mu (n)}{n^2}\sum\limits_{k=1}^{f\,n}k\left(\delta\left(\frac{k}{n}+z\right)-\delta\left(\frac{k}{n}-z\right)\right)$
I believe the reason for the seeming discrepancies between the Fourier transforms of the distributional and Fourier series representations for $U(x)$, $U'(x)$, and $U''(x)$ is the idealization of the Fourier transforms of $sin$ and $cos$ functions as Dirac delta ($\delta$) functions. Note this discrepancy exists even for the Fourier transforms of the distributional and Fourier series representations of the Dirac comb. In the case of the distributional and Fourier series representations of the Dirac comb each representation transforms into the other representation which I suppose makes the discrepancy a bit easier to accept, but the case being explored here is considerably different.
The bilateral Laplace transforms of the Fourier series representations of $U(x)$, $U'(x)$, and $U''(x)$ don't converge for $Re(y)=0$, and consequently they cannot be evaluated at $y=2\,\pi\,i\, z$ to obtain their corresponding Fourier transforms. However, the contribution of the right and left-half planes can be evaluated at $y=2\,\pi\,i\,z+\epsilon$ and $y=2\,i\,\pi\,z-\epsilon$ respectively and summed together to approximate their corresponding Fourier transforms for $z\in\mathbb{R}$ as defined in the formulas below.
(33) $\quad\mathcal{FT}_x[U(x)](z)\approx 2\sum\limits_{n=1}^N\mu(n)\,n\sum\limits_{k=1}^{f\,n}\left(\frac{1}{(2\,\pi\,k)^2+n^2(2\,\pi\,i\,z+\epsilon)^2}-\frac{1}{(2\,\pi\,k)^2+n^2(2\,i\,\pi\,z-\epsilon)^2}\right)\,,\,z\in\mathbb{R}_{\ne 0}$
(34) $\quad\mathcal{FT}_x[U'(x)](z)\approx 2\sum\limits_{n=1}^N\mu(n)\,n\sum\limits_{k=1}^{f\,n}\left(\frac{2\,i\,\pi\,z+\epsilon}{(2\,\pi\,k)^2+n^2(2\,i\,\pi\,z+\epsilon)^2}-\frac{2\,\pi\,i\,z-\epsilon}{(2\,\pi\,k)^2+n^2(2\,\pi\,i\,z-\epsilon)^2}\right)\,,\,z\in\mathbb{R}$
(35) $\quad\mathcal{FT}_x[U''(x)](z)\approx -8\,\pi^2\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\left(\frac{k^2}{(2\,\pi\,k)^2+n^2(2\,i\,\pi\,z+\epsilon)^2}-\frac{k^2}{(2\,\pi\,k)^2+n^2(2\,\pi\,i\,z-\epsilon)^2}\right)\,,\,z\in\mathbb{R}$
The following three plots illustrate the Fourier transforms of the distributional representations of $U(x)$, $U'(x)$, and $U''(x)$ defined in (25), (26), and (27) above in blue and the approximations to the Fourier transforms of the Fourier series representations of $U(x)$, $U'(x)$, and $U''(x)$ defined in (33), (34), and (35) above in orange. All three plots use the same evaluation limits $N=101$, $f=4$, and $\epsilon=0.1$. The second plot below corresponds to the evaluation of the real part of the Fourier transform of $U'(x)$, and the first and third plots below correspond to the evaluations of the imaginary parts of the Fourier transforms of $U(x)$ and $U''(x)$ respectively.
Figure (4): Illustration of $\Im$ Part of Formula (33) for $\mathcal{FT}_x[U(x)](z)=-\frac{i\,\cos(2\,\pi\,z)}{\pi\,z}$
Figure (5): Illustration of $\Re$ Part of Formula (34) for $\mathcal{FT}_x[U'(x)](z)=2\,\cos(2\,\pi\,z)$
Figure (6): Illustration of $\Im$ Part of Formula (35) for $\mathcal{FT}_x[U''(x)](z)=4\,i\,\pi\,z\,\cos(2\,\pi\,z)$
The Mellin transforms of the distributional representations of $U(x)$, $U'(x)$, and $U''(x)$ defined in (1), (2), and (3) above are as follows.
(36) $\quad\mathcal{M}_x[U(x)](s)=-\frac{1}{s},\quad\Re(s)<0$
(37) $\quad\mathcal{M}_x[U'(x)](s)=1$
(38) $\quad\mathcal{M}_x[U''(x)](s)=1-s$
The Mellin transforms of the $sin$ and $cos$ terms associated with the Fourier series representations of $U(x)$, $U'(x)$, and $U''(x)$ are as follows.
(39) $\quad\mathcal{MT}_x\left[\sin\left(\frac{2\,\pi\,k\,x)}{n}\right)\right](s)=(2\pi )^{-s}\,\sin\left(\frac{\pi\,s}{2}\right)\,\Gamma(s)\,\left(\frac{k}{n}\right)^{-s}$
(40) $\quad\mathcal{MT}_x\left[\cos\left(\frac{2\,\pi\,k\,x)}{n}\right)\right](s)=(2\,\pi)^{-s}\,\cos\left(\frac{\pi\,s}{2}\right)\,\Gamma(s)\,\left(\frac{k}{n}\right)^{-s}$
Term-wise integration of the Fourier series representation of $U(x)$, $U'(x)$, and $U''(x)$ defined in (11), (12), and (13) above implies the following Mellin transforms for the Fourier series representation of each of these functions. These transforms can be shown to be equivalent to the Mellin transforms of the distributional representations defined in (36), (37), and (38) above via analytic continuation and the definition of the Riemann zeta functional equation.
(41) $\quad\mathcal{M}_x[U(x)](s)=\frac{1}{\pi}\,(2\,\pi)^{-s}\,\sin\left(\frac{\pi\,s}{2}\right)\,\Gamma(s)\sum\limits_{n=1}^\infty\mu(n)\,\left(\frac{1}{n}\right)^{-s}\sum\limits_{k=1}^\infty k^{-1-s}$
(42) $\quad\mathcal{M}_x[U'(x)](s)=2\,(2\,\pi)^{-s}\,\cos\left(\frac{\pi\,s}{2}\right)\,\Gamma(s)\sum\limits_{n=1}^\infty\mu(n)\,\left(\frac{1}{n}\right)^{1-s}\sum\limits_{k=1}^\infty k^{-s}$
(43) $\quad\mathcal{M}_x[U''(x)](s)=-4\,\pi\,(2\,\pi)^{-s}\,\sin\left(\frac{\pi\,s}{2}\right)\,\Gamma(s)\sum\limits_{n=1}^\infty\mu(n)\,\left(\frac{1}{n}\right)^{2-s}\sum\limits_{k=1}^\infty k^{1-s}$
Formulas (44), (45), and (46) below illustrate the analytic continuations of formulas (41), (42), and (43) above are equivalent to the Mellin transforms of the distributional representations defined in (36), (37), and (38) above per the definition of the Riemann zeta functional equation. These results are achieved by replacing the sums over $n$ and $k$ in formulas (41), (42), and (43) above with their corresponding zeta functions and then simplifying using the definition of the Riemann zeta functional equation.
(44) $\quad\mathcal{M}_x[U(x)](s)=\frac{1}{\pi}\,(2\,\pi)^{-s}\,\sin\left(\frac{\pi\,s}{2}\right)\,\Gamma(s)\,\frac{\zeta(1+s)}{\zeta(-s)}=-\frac{1}{s}$
(45) $\quad\mathcal{M}_x[U'(x)](s)=2\,(2\,\pi)^{-s}\,\cos\left(\frac{\pi\,s}{2}\right)\,\Gamma(s)\,\frac{\zeta(s)}{\zeta(1-s)}=1$
(46) $\quad\mathcal{M}_x[U''(x)](s)=-2\,(2\,\pi)^{1-s}\,\sin\left(\frac{\pi\,s}{2}\right)\,\Gamma(s)\,\frac{\zeta(s-1)}{\zeta(2-s)}=1-s$
Note the Fourier series representation of $U'(x)$ represents $\delta(x-1)$ in the right-half plane and the Mellin transform $\mathcal{M}_x[\delta(x-1)](s)=1$. I'm currently investigating convergence of formulas derived from convolutions such as (47) to (49) below where the Fourier series representation of $U'(x)$ is substituted for $\delta(x-1)$ in the convolutions.
(47) $\quad g(y)=\delta(x-1)\,*_\mathcal{M_1}\,g(x)=\int_0^\infty\delta(x-1)\,g\left(\frac{y}{x}\right)\,\frac{dx}{x}$
(48) $\quad g(y)=\delta(x-1)\,*_\mathcal{M_2}\,g(x)=\int_0^\infty\delta(x-1)\,g(y\,x)\,\,dx$
(49) $\quad g(y)=\delta(x-1)\,*_\mathcal{M_3}\,g(x)=\int_0^\infty\delta(x-1)\,g(y+1-x)\,\,dx$
It's also possible to derive formulas for derivatives of functions using the Fourier series representations of the derivatives of $\delta(x-1)$ via relationships such as the following.
(50) $\quad g^{(n)}(y)=(-y)^{-n}\left(\delta^{(n)}(x-1)\,*_{\mathcal{M}_2}\,g(x)\right)=(-y)^{-n}\int_0^\infty\delta^{(n)}(x-1)\,g(y\,x)\,dx$
(51) $\quad g^{(n)}(y)=\delta^{(n)}(x-1)\,*_{\mathcal{M}_3}\,g(x)=\int_0^\infty\delta^{(n)}(x-1)\,g(y+1-x)\,dx$
An initial formula derived via a convolution such as those described above may be used to derive additional formulas for related functions via differentiation, integration, Laplace normal/inverse transforms, Mellin normal/inverse transforms, Hankel transforms, and in rare cases Fourier normal/inverse transforms.
I've derived a considerable number of formulas for a variety of functions using the techniques described above, but these formulas vary widely in complexity and a few of them don't seem to converge. The following formulas are mostly toward the simpler end of the spectrum and all seem to exhibit observational evidence of convergence under the general conditions specified in (8) above and the specific conditions specified for each formula below. The $E_m(y)$ function below (typically referred to as $E_n(y)$) is one of the more difficult functions with respect to determining convergence conditions as it's a function of two complex variables ($m$ and $y$).
(52) $\quad e^{-y}=2\,y\sum\limits_{n=1}^N\mu(n)\,n\sum\limits_{k=1}^{f\,n}\frac{1}{4\,\pi^2\,k^2+n^2\,y^2}\,,\quad\Re[y]>0$
(53) $\quad e^{-y}=-\frac{8\,\pi^2}{y}\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\frac{k^2}{4\,\pi\,^2\,k^2+n^2\,y^2}\,,\quad\Re[y]>0$
(54) $\quad e^{-y}=-\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\log\left(\left(\frac{2\,\pi\,k}{n\,y}\right)^2+1\right),\quad\Re[y]>0$
(55) $\quad\log(y)=\frac{1}{\pi }\sum\limits_{n=1}^N\mu(n)\sum\limits_{k=1}^{f\, n}\frac{\pi\,\sin^2\left(\frac{k\,\pi\,(y-1)}{n}\right)-\sin\left(\frac{2\,k\,\pi\,(y-1)}{n}\right)\,Ci\left(\frac{2\,k\,\pi\,(y-1)}{n}\right)+\cos\left(\frac{2\,k\,\pi\,(y-1)}{n}\right)\,Si\left(\frac{2\,k\,\pi\,(y-1)}{n}\right)}{k},\\ \qquad\qquad\qquad\qquad\qquad\qquad\qquad\qquad y>1$
(56) $\quad\cos(y)=2\,e\sum\limits_{n=1}^N\mu(n)\,n\sum\limits_{k=1}^{f\,n}\frac{n^2\,\left(y^2+1\right)+4\,\pi^2\,k^2}{\left(n^2\,\left(y^2-1\right)-4\,\pi^2\,k^2\right)^2+4\, n^4\,y^2},\quad y\in\mathbb{R}$
(57) $\quad\sin(y)=4\sum\limits_{n=1}^N\mu(n)\sum\limits_{k=1}^{f\,n}\frac{\pi\,k\,\sin (y+1)\,\sin \left(\frac{2\,\pi^2\,k}{n}\right)-n \cos (y+1) \cos ^2\left(\frac{\pi^2\,k}{n}\right)}{n^2-4\,\pi ^2\,k^2},\quad Re(y)\ne 0\lor y=0$
(58) $\quad sinc(y)=\frac{\sin (y)}{y}=2\,e\sum\limits_{n=1}^N\mu (n)\,n\sum\limits_{k=1}^{f n}\frac{n^2\,\left(y^2+1\right)-4\,\pi^2\,k^2}{\left(n^2\,\left(y^2-1\right)-4\,\pi^2\,k^2\right)^2+4\,n^4\, y^2},\quad y\in\mathbb{R}$
(59) $\quad sech(y)=\frac{\pi}{y}\sum\limits_{n=1}^{N}\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n} sech\left(\frac{k\,\pi^2}{n\,y}\right),\quad\Re(y)>0$
(60) $\quad erf(y)=\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\Gamma\left(0,\frac{k^2\,\pi^2}{n^2\,y^2}\right)\,,\quad\Re(y)>0$
(61) $\quad erfc(y)=1-erf(y)=2\,\pi^{-3/2}\sum\limits_{n=1}^N\mu(n)\sum\limits_{k=1}^{f\,n}\frac{F\left(\frac{k\,\pi}{n\,y}\right)}{k}\,,\quad\Re(y)>0$
(62) $\quad F(y)=\frac{1}{2}\pi^{3/2}\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n} erfc\left(\frac{\pi\, k}{n\,y}\right)\,,\quad y\in\mathbb{R}\quad\text{(Dawson function)}$
(63) $\quad K_0(y)=\pi\sum\limits_{n=1}^N\mu(n)\sum\limits_{k=1}^{f\,n}\frac{1}{\sqrt{4\,\pi^2\,k^2+n^2\,y^2}}\,,\quad\Re(y)>0$
(64) $\quad Si(y)=-\pi\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\left( \begin{array}{cc} \{ & \begin{array}{cc} \log\left(\frac{2\,k\,\pi}{n\,y}\right) & 2\,k\,\pi<n\,y \\ 0 & \text{True} \\ \end{array} \\ \end{array} \right),\quad y>0$
(65) $\quad Ei(y)=-\frac{1}{2\,\pi}\sum\limits_{n=1}^N\mu(n)\sum\limits_{k=1}^{f\,n} \frac{\pi+2\,\cot^{-1}\left(\frac{2\,\pi\,k}{n\,y}\right)}{k},\quad y<0$
(66) $\quad E_1(y)=\frac{1}{\pi}\sum\limits_{n=1}^N\mu(n)\sum\limits_{k=1}^{f\,n}\frac{\tan ^{-1}\left(\frac{2\,\pi\,k}{n\,y}\right)}{k},\quad Re[y]>0$
(67) $\quad E_m(y)=\frac{2}{m\,y}\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\,_2F_1\left(1,\frac{m}{2};\frac{m+2}{2};-\left(\frac{2\,\pi\,k}{n\,y}\right)^2\right),\\$ $\qquad\qquad\qquad\qquad\Re(y)>0\,\land\,\Re(m)\geq 0\,\land\,m\neq 0$
(68) $\quad\frac{1}{\Gamma[s]}=e\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\left(\left(1+\frac{2\,i\,\pi\,k}{n}\right)^{-s}+\left(1-\frac{2\,i\,\pi\,k}{n}\right)^{-s}\right),\quad\Re[s]>0$
(69) $\quad\Gamma(0,\,s)=e\sum\limits _{n=1}^N\mu(n)\sum\limits_{k=1}^{f\,n}\left(\frac{\log\left(1+\frac{n+2\,i\,\pi\,k}{n\,s}\right)}{n+2\,i\,\pi\,k}+\frac{\log \left(1+\frac{n-2\,i\,\pi\,k}{n\,s}\right)}{n-2\,i\,\pi\,k}\right),\quad s>0$
(70) $\quad\Gamma[s]=e\,\pi\,\csc\,(\pi\,s)\sum\limits_{n=1}^N\frac{\mu(n)}{n}\sum\limits_{k=1}^{f\,n}\left(\left(\frac{n}{n+2\,i\,\pi\,k}\right)^{1-s}+\left(\frac{n}{n-2\,i\,\pi\,k}\right)^{1-s}\right),\quad-1<\Re(s)<1$
Most of the formulas above are illustrated at the following link. I typically use $f=4$ for evaluation plots as most of the formulas are much more sensitive to the magnitude of $N$ than they are to the magnitude of $f$. I'd appreciate feedback anyone might have with respect to convergence of these formulas.
Illustration of Formulas Derived From Fourier Series Representation of $U'(x)$ and $U''(x)$
The Fourier series representation of $U(x)$ is an example of what I refer to as a method 1 Fourier series. Similar Fourier series can be derived for the log-step staircase function $T(x)$ and prime-counting functions such as the base prime-counting function $\pi(x)$, Riemann's prime-power counting function $\Pi(x)$, the first Chebyshev function $\vartheta(x)$, and the second Chebyshev function $\psi(x)$.
Assuming $a\in\mathbb{R}$, the $U(x)$ function can be shifted by subtraction of parameters as illustrated in (71) below. Formula (71) below evaluates to $\theta(x-a)$ for $x\ge a-1$. This representations of $\theta(x-a)$ is the basis for what I refer to as the method 2 Fourier series representation of prime-counting functions. Since both $\theta$ functions move in the same direction when shifting $U(x)$ via subtraction of parameters, the lower evaluation bound must be restricted to $x\ge a-1$ when evaluating $U(x-(a-1))$ to avoid contribution of the $\theta$ function originally in the left-half plane.
(71) $\quad U(x-(a-1))=-1+\theta(x-(a-1)+1)+\theta(x-(a-1)-1)\\$ $\qquad\qquad\qquad\qquad\qquad=-1+\theta(x-(a-2))+\theta(x-a)$
Assuming $a\in\mathbb{R}$ and $a>1$, the $U(x)$ function can also be shifted by division of parameters as illustrated in (72) below. Formula (72) below evaluates to $\theta(x-a)$ for $x\ge 0$. This representation of $\theta(x-a)$ is the basis for what I refer to as the method 3 Fourier series representation of prime-counting functions. Note that in this case the two $\theta$ functions move in opposite directions (since $a>1$), and the $\theta$ function in the left-half plane can be ignored when evaluating formulas for $x\ge 0$ which is the primary interest with respect to evaluation of formulas related to prime-counting functions.
(72) $\quad U\left(\frac{x}{a}\right)=-1+\theta\left(\frac{x}{a}+1\right)+\theta\left(\frac{x}{a}-1\right)=-1+\theta(x+a)+\theta(x-a)$
Method 3 has the advantage over method 2 that it's not necessary to restrict the lower evaluation bound when evaluating $\theta(x-a)$, but has the disadvantage that conditional convergence becomes a bit more complicated. Additional terms must be evaluated in order to obtain convergence, and this leads to longer evaluation times.
The following three plots illustrate method 1, method 2, and method 3 Fourier series representations related to the first-order derivative $\psi'(x)$ of the second Chebyshev function. The method 1 representation in the first plot is for $\psi'(x)-1$, whereas the method 2 and method 3 representations illustrated in the second and third plots are both for $\psi'(x)$. All three plots are evaluated at $f=4$. The orange curve illustrated in the plots is the reference function $2\,f\log(x)$ and the horizontal dashed grid-lines are at $2\,f\log(2)$ and $2\,f\log(3)$. The red discrete portions of the plots illustrate all three Fourier series representations exhibit the same strict convergence to exactly to $2\,f$ times the step size of $\psi(x)$ at positive integer values of $x$.
Figure (7): Illustration of Method 1 Fourier Series Representation of $\psi(x)-1$
Figure (8): Illustration of Method 2 Fourier Series Representation of $\psi(x)$
Figure (9): Illustration of Method 3 Fourier Series Representation of $\psi(x)$
Personally I find the method 2 and method 3 Fourier series representations of prime-counting functions somewhat artificial compared with the method 1 Fourier series representation. The method 2 Fourier series representation seems particularly artificial to me since it requires a different lower evaluation bound be used to evaluate each different instance of $\theta(x-a)$.
3/26/2018 Update:
The following link defines and illustrates a general method for derivation of a Fourier series representation for $f(x)=\sum\limits_{n=1}^x a(n)$ related to the Dirichlet series $F(s)=\sum\limits_{n=1}^\infty\frac{a(n)}{n^s}$.
Derivation of Fourier Series Representation for $f(x)=\sum\limits_{n=1}^x a(n)$
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2020-01-21 23:18:26
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https://www.physicsforums.com/threads/tension-in-a-rope-at-an-angle-with-a-hanging-mass.780200/
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# Tension in a rope at an angle with a hanging mass
## Homework Statement
A rope is connected between two fixed points that are separated horizontally from one another by 10 m. The point on the left at a height of 5 m [coordinates (0,5m)], and point on the right is at a height of 10 m [coordinates
(10m,10m)]. A 100 lbs weight hangs from the rope, attached at the location (5m,6m), separating the rope into two segments. What is the tension in each segment? Neglect the weight of the rope. See attached image
## Homework Equations
T1 = mg sin ϴ1
T2 = mg sin ϴ2[/B]
## The Attempt at a Solution
I fist converted the 100 lb weight to 444.8N. I was thinking that the problem would be similar to one with a horizontal rope with the ends at equal heights, and solved for both ϴ1 and ϴ2 then used these values to calculate the tension in each segment. I got T1 = 87.2 N and T2 = 278.1 N.
Does this seem correct?
#### Attachments
• 12 - 1.png
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Last edited:
collinsmark
Homework Helper
Gold Member
Hello Wolfmannm,
Welcome to PF! :)
## Homework Statement
A rope is connected between two fixed points that are separated horizontally from one another by 10 m. The point on the left at a height of 5 m [coordinates (0,5m)], and point on the right is at a height of 10 m [coordinates
(10m,10m)]. A 100 lbs weight hangs from the rope, attached at the location (5m,6m), separating the rope into two segments. What is the tension in each segment? Neglect the weight of the rope. See attached image
## Homework Equations
T1 = mg sin ϴ1
T2 = mg sin ϴ2[/B]
## The Attempt at a Solution
I fist converted the 100 lb weight to 444.8N. I was thinking that the problem would be similar to one with a horizontal rope with the ends at equal heights, and solved for both ϴ1 and ϴ2 then used these values to calculate the tension in each segment. I got T1 = 87.2 N and T2 = 278.1 N.
Does this seem correct?
Those answers (87.2 N and 278.1 N) are not correct. There must be a mistake in there somewhere.
Post your steps on how you obtained your answers, and maybe we can help pinpoint what went wrong.
[Edit: And also, the equations that you listed in your relevant equations section are incorrect for this problem.]
Last edited:
CWatters
Homework Helper
Gold Member
Can you show your working? T2 sounds a too low, it must be > 444.8N.
I haven't worked right through to the answer (it's 11pm here) but I have four equations and four unknowns. One of my equations sums the vertical components to zero....
T2Sinϴ2 - 444.8 - T1Sinϴ1 = 0
so
T2 = (444.8 + T1Sinϴ1) / Sinϴ2
or
T2 = 444.8/Sinϴ2 + T1Sinϴ1/Sinϴ2
Sinϴ2 is < 1 so that implies T2 > 444.8N
I calculated ϴ1 to be approx -11.3° and ϴ2 to be approx 38.7°. Do these seem reasonable?
I see where those equations are incorrect. I didn't account for forces acting in more than on direction. Is the last equation
T2Cosϴ2 - 444.8 - T1Cosϴ1 = 0 ?
collinsmark
Homework Helper
Gold Member
I calculated ϴ1 to be approx -11.3° and ϴ2 to be approx 38.7°. Do these seem reasonable?
Those numbers seem reasonable, yes, with the possible exception of the negative sign on the "-11.3o". That depends on how you interpret the angle. Given your diagram, both angles should be positive numbers, given the way you have defined them in the diagram, I would think.
I see where those equations are incorrect. I didn't account for forces acting in more than on direction. Is the last equation
T2Cosϴ2 - 444.8 - T1Cosϴ1 = 0 ?
Something is not quite right here. The tension times the cosine of the angle is the horizontal component of the particular tension, given how you have defined the angles in your diagram. The mass' weight acts in the vertical direction, not the horizontal.
Eventually you will need two simultaneous equations to combine. One for the sum of vertical forces, and the other for the horizontal forces.
collinsmark
Homework Helper
Gold Member
By the way, if you're ever in doubt about which trigonometric function to use, recall,
$$\sin \theta = \mathrm{\frac{opposite}{hypotenuse}}$$
$$\cos \theta = \mathrm{\frac{adjacent}{hypotenuse}}$$
$$\tan \theta = \mathrm{\frac{opposite}{adjacent}}$$
I'm sure that you probably already know that. But my advice here is to commit those to memory in such a way that they become second nature.
CWatters
Homework Helper
Gold Member
I calculated ϴ1 to be approx -11.3° and ϴ2 to be approx 38.7°. Do these seem reasonable?
They are reasonable but don't quite satisfy two of my equations. If I have understood correctly the "attached at the location (5m,6m)" means that horizontally the dimensions give you...
5Cosϴ1 + 6Cosϴ2 = 10
If I substitute your values for the angles I get = 9.6
I see where those equations are incorrect. I didn't account for forces acting in more than on direction. Is the last equation
T2Cosϴ2 - 444.8 - T1Cosϴ1 = 0 ?
As colinsmark said.. That's not correct. Are you trying to sum the horizontal or vertical components? It would help if you show us all 4(?) of your initial simultaneous equations with a one line explanation of each.
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2021-05-09 20:54:57
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https://math.stackexchange.com/questions/3211780/components-of-a-vector-in-polar-coordinates
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# Components of a vector in polar coordinates
The problem is the following:
A vector in the $$xy$$ plane starts at the point $$(0,-2)$$ and ends (where the tip is) at position $$(0,1)$$. Write its components in polar coordinates.
The problem suggests to start writing the relation between the basis vectors
$$\partial_x = \cos\theta \ \partial_r -\dfrac{\sin\theta}{r} \ \partial_\theta$$ and $$\partial_y=\sin\theta \ \partial_r + \dfrac{\cos\theta}{r} \ \partial_\theta$$
I got to the point above, but doesn't know how to proceed from here.
Note: I am starting to learn differential geometry so any clues on how to proceed will be helpful.
The vector starts at $$(0,-2)$$ and ends at $$(0,1)$$, therefore $$\vec{v}=[0,3]$$.
Notice that the horizontal component is $$0$$ and the vertical component is $$3$$, so the magnitude is simply $$3$$.
The angle (argument) is $$\displaystyle \frac{π}{2}$$ because the vector points upward.
Written in polar coordinates, it could be written as $$\displaystyle (r, \theta)=\left(3,\frac{π}{2}\right)$$, or $$\large \displaystyle 3e^{\frac{π}{2}}$$, or $$3i\sin \left(\frac{π}{2}\right)$$.
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2021-12-01 08:39:01
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https://stats.stackexchange.com/questions/200891/sample-variance-degrees-of-freedom-two-stage-least-squares
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# Sample variance degrees of freedom (two-stage least squares)
Let's say I have one endogenous variable $X_1$ in the linear model
$$Y=X_1\beta$$
and two instrumental variables $Z_1$ and $Z_2$ (strongly correlated with $X_1$ but not $Y$).
I compute the two-stage least squares in the following way:
$$\widehat{\beta}_{2SLS} = [X'Z(Z'Z)^{-1}Z'X]^{-1}[X'Z(Z'Z)^{-1}Z'y]$$
I'm trying to understand the number of degrees of freedom in this situation in order to correct the calculation of the sample variance of my final regression model. I have two options:
1. According to Multiple linear regression degrees of freedom, I would have $N-2$ degrees of freedom.
2. However, because during the first stage of 2SLS I regress $X_1$ on the $Zs$, i.e., I run OLS on the linear model
$$X_1=\delta_1Z_1 + \delta_2Z_2$$
and in this case we have two predictor variables ($Z_1$ and $Z_2$), so perhaps I have $N-3$ degrees of freedom.
Any hints about which one works here?
Either is fine, asymptotically. Recall that the main goal in the degrees of freedom corrections of the error variance estimate in OLS is to render the estimate $s^2$ an unbiased estimator of $\sigma^2$, and also a required ingredient to $t$- and $F$-finite-sample distribution theory in normal regression models.
$$\frac{1}{n}\sum_i(y_i-x_i\hat\beta_{2SLS})^2$$
is consistent for $\sigma^2$. Now, rescaling this expression by $\frac{n}{n-K}$ for any finite $K$ such as 2 or 3 will not matter asymptotically, as $\frac{n}{n-K}\to1$.
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2019-11-19 11:14:15
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https://wilcoxen.maxwell.insightworks.com/pages/4681.html
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# Fall 2018 Final Exam Solution
Here are the final numerical results for each section of the exam. You can use them to check your work if you do the exam for practice. If you have trouble with the problems, or don't get the answers shown here, stop by during office hours or make and appointment and we can go over them.
### Question 4
(a) EV of federal policy = -$2B; EV of state policy = -$200 M. Neither adopts.
(b) EV to state with the federal policy in place = +$100 M (-$200 M + $300 M); state adopts. EV to federal government of offering the grant and then deciding whether or not to implement its own policy based on the outcome at the state level:$1.5 B; the federal government would offer the grant.
### Question 5
Q = 28; P = $700; profit =$920.
### Question 6
Q = 40; P = $5,000; profit =$160,000.
(a) EV = -$201 k; firm does not undertake it. (b) PV of CS =$3.409 M; EV of CS = $681 k. ### Question 8 EV to the firm =$200 k; the firm would undertake the project. EV to the government = $280 k; the government would want to offer the policy. Not required but worth noting: the net gains to the firm and the government are$480 k, which is exactly the sum of the expected CS ($681 k) and the firm's EV without the policy (-$201 k).
URL: https://wilcoxen.maxwell.insightworks.com/pages/4681.html
Peter J Wilcoxen, The Maxwell School, Syracuse University
Revised 01/04/2019
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2020-04-07 04:13:55
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https://www.techwhiff.com/learn/a-start-up-firm-is-making-an-initial-investment/38792
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# A start-up firm is making an initial investment in new plant and equipment. Assume that currently...
###### Question:
A start-up firm is making an initial investment in new plant and equipment. Assume that currently its equipment must be depreciated on a straight-line basis over 10 years, but Congress is considering legislation that would require the firm to depreciate the equipment over 7 years. If the legislation becomes law, which of the following would occur in the year following the change?
Select one:
a. The firm’s operating income (EBIT) would increase.
b. The firm’s tax payments would increase.
c. The firm’s net cash flow would decrease.
d. The company’s depreciation would increase.
e. The firm’s taxable income would increase.
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2022-11-28 08:33:59
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https://math.stackexchange.com/questions/867449/possible-to-determine-if-a-more-compact-solution-to-a-linear-recurrence-exists
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# Possible to determine if a more 'compact' solution to a linear recurrence exists?
Given a linear a recurrence relation. It is possible to express a solution in terms of summations, products, and the coefficients which appear in the recurrence. For example, in the case of a single index, assuming $x_0$ constant:
$x_n = \sum_{j=0}^{n-1}[a_{n,j}x_j] \\ \quad = (a_{n,0} + \sum_{j=1}^{n-1}[a_{n,j}a_{j,0}] + \sum_{j_1=2}^{n-1} \sum_{j_2=1}^{j_1-1}[a_{n,j_1}a_{j_1,j_2}a_{j_2,0}] + . . . \\ \qquad + \sum_{j_1=n-1}^{n-1}\sum_{j_2=n-2}^{j_1-1}...\sum_{j_{n-1}=1}^{j_{n-2}-1}[a_{n,j_1}a_{j_1,j_2}...a_{j_{n-2},j_{n-1}}a_{j_{n-1},0}])x_0$
What I'm interested in, is whether or not it's possible to determine if a more 'compact' solution exists in terms of addition, subtraction, multiplication, and division, and the original coefficient functions in the recurrence, or, more generally, in terms of some specified set of functions and/or constants (e.g. elementary functions). By 'compact' I mean 'compact' with respect to a specified set of functions and/or constants, call it the 'representation set'. To clarify further, a form which requires less function calls than the summation form given above (or more generally some specified form which is also in terms of the supplied set of functions).
If it is possible to determine if a more compact form exists, is there an algorithm to find such a form?
I'll give two examples to motivate the gist of what I'm getting at.
For each natural number or zero, m, let $e_m$ represent the $m^{th}$ elementary symmetric polynomial where we allow multiset inputs of arbitrary length. i.e. $m>0$ then $e_m$[$\emptyset$]$= 0$, $\forall x (e_0[x] = 1)$, $\forall x = (x_j)_{j=1}^{n} (e_m[x] = \sum_{1 \leq j_1<j_2<...<j_m \leq n}[x_{j_1}x_{j_2}...x_{j_m}])$
Example 1:
Consider the binomial coefficient recurrence (with its typical boundary conditions) $${n \choose m} = {n-1 \choose m} + {n-1 \choose m-1}$$ The typical representation of the solution is in terms of factorials: $${n \choose m} = \frac{n!}{m!(n-m)!}$$ Which is easily converted into the product form: $${n \choose m} = \prod_{j=1}^{m}[\frac{n-(j-1)}{j}]$$ On the other hand if we didn't know this and naively expanded the summation in the recurrence we would end up with $${n \choose m} = \sum_{1 \leq j_1<j_2<...<j_m \leq n}[1]$$ Furthermore if we allow elementary symmetric polynomials in our representation set then we can write $${n \choose m} = e_m[(1)_{j=1}^{n}]$$
Example 2:
Consider the recurrence: $$e_{m,n} = e_{m,n-1}+ne_{m-1,n-1} \land e_{0,n} = 1 \land (m>n \lor m<0) \rightarrow (e_{m,n} = 0)$$ If we expand the sum and refer to some properties of the elementary symmetric polynomials we get $$e_{m,n} = \sum_{1 \leq j_1<j_2<...<j_m \leq n}[j_1 j_2...j_m] = e_m[(j)_{j=1}^{n}]$$ but this summation can also be more compactly represented by noticing the relation to the stirling numbers of the first kind. If $s_{m,n}$ represents the stirling number of the first kind, then we can use the relation $e_{m,n} = (-1)^{m}s_{n+1,n+1-m}$ and the explicit formula for s: $$s_{n,m}=\frac{(2n-m)!}{(m-1)!}\sum_{k=0}^{n-m}\frac{1}{(n+k)(n-m-k)!(n-m+k)!}\sum_{j=0}^{k}\frac{(-1)^{j} j^{n-m+k} }{j!(k-j)!}.$$ to obtain a formula for $e_{m,n}$
• Are you familiar with the theory in the case of linear recurrence relations in one variable? In this case one can write down an answer involving no summation symbols. – Qiaochu Yuan Jul 14 '14 at 23:39
• You're referring to the case of constant coefficients where one considers the the auxiliary polynomial and proceeds to write the solution as a linear combination of its roots? – DAS Jul 15 '14 at 4:17
• Yep. In more than one variable it's sometimes possible to do nice things involving finding the generating function. – Qiaochu Yuan Jul 15 '14 at 4:22
• I do know a little bit about generating functions although I have not extensively studied them. I'm aware that it is sometimes possible to use a generating function to obtain a 'nice' solution via algebraic manipulations. However, I do not think a generating function will always help you out. Even if it could help you out, unless you have an extensive amount of experience with them or get lucky it seems like there is a good chance you'd miss out on this fact, perhaps after some extensive (frustrating) algebraic manipulation. – DAS Jul 16 '14 at 7:01
• So, I'd be interested in knowing if there is a way to determine if a solution more efficient than expanding out the recurrence summation is obtainable via manipulation of some generating function(s), instead of a 'maybe'. Then manipulating some generating function(s) for a long time, ending up with nothing, and then not even knowing if the generating function approach won't help or if you just missed something. – DAS Jul 16 '14 at 7:04
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2019-05-23 14:57:07
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https://projecteuclid.org/euclid.aaa/1395858397
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## Abstract and Applied Analysis
### An Averaging Principle for Stochastic Differential Delay Equations with Fractional Brownian Motion
Yong Xu, Bin Pei, and Yongge Li
#### Abstract
An averaging principle for a class of stochastic differential delay equations (SDDEs) driven by fractional Brownian motion (fBm) with Hurst parameter in $(\mathrm{1}/\mathrm{2},\mathrm{1})$ is considered, where stochastic integration is convolved as the path integrals. The solutions to the original SDDEs can be approximated by solutions to the corresponding averaged SDDEs in the sense of both convergence in mean square and in probability, respectively. Two examples are carried out to illustrate the proposed averaging principle.
#### Article information
Source
Abstr. Appl. Anal., Volume 2014, Special Issue (2013), Article ID 479195, 10 pages.
Dates
First available in Project Euclid: 26 March 2014
Permanent link to this document
https://projecteuclid.org/euclid.aaa/1395858397
Digital Object Identifier
doi:10.1155/2014/479195
Mathematical Reviews number (MathSciNet)
MR3166618
Zentralblatt MATH identifier
07022457
#### Citation
Xu, Yong; Pei, Bin; Li, Yongge. An Averaging Principle for Stochastic Differential Delay Equations with Fractional Brownian Motion. Abstr. Appl. Anal. 2014, Special Issue (2013), Article ID 479195, 10 pages. doi:10.1155/2014/479195. https://projecteuclid.org/euclid.aaa/1395858397
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2019-10-23 15:53:12
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|
https://www.physicsforums.com/threads/calculus-i-problem-i-cant-solve.226770/
|
# Calculus I problem I can't solve
Here's the problem:
$$d/dx(f(3x^5)) = 8x^2$$
Find $$f'(x)$$
After applying the chain rule:
$$f'(3x^5)(15x^4) = 8x^2$$
$$f'(3x^5) = 8/(15x^2)$$
It's not apparent to me how I proceed from here to find $$f'(x)$$. I tried dividing the expression on the right by three and taking the fifth root but that does not seem to be right. Any help would be appreciated!
Related Calculus and Beyond Homework Help News on Phys.org
HallsofIvy
I see what you're saying, but isn't du/dx equal to $$15x^4$$, not $$15x$$? That would make df/du equal to $$(8/15x^2)$$. Therefore, substituting x= (u/3)1/5 gives a result of (8/15)(3^(2/5)/u^(2/5)).
Substituting u by x to get f'(x) would get a final solution of $$8/15x^2$$, which is what I started with above for $$f'(3x^5)$$, which I don't think is the correct answer.
|
2019-12-08 03:37:31
|
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8916115164756775, "perplexity": 328.65590123560145}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575540504338.31/warc/CC-MAIN-20191208021121-20191208045121-00198.warc.gz"}
|
https://zbmath.org/?q=an:0891.53044
|
## Stability of hypersurfaces with constant $$r$$-mean curvature.(English)Zbl 0891.53044
The authors show that in the standard spaces $$\overline M^{n+1} (c)$$ of constant curvature $$c$$, the compact (closed) hypersurfaces of constant $$r$$-mean curvature, $$r\in \{1, \dots, n\}$$, are critical points for some variational problem. In this class, the geodesic spheres are characterized as the stable ones, i.e., at these “points” the second derivative of the functional under consideration is $$\geq 0$$ with respect to variations “keeping the balance of volume zero”. The special situations $$r=1$$ resp. $$c=0$$ resp. $$(r,c) =(2,1)$$ were already investigated by J. L. Barbosa, M. P. do Carmo and J.-H. Eschenburg [Math. Z. 197, 123-138 (1988; Zbl 0653.53045)] resp. H. Alencar, M. P. do Carmo and H. Rosenberg [Ann. Global Anal. Geom. 11, 387-395 (1993; Zbl 0816.53031)] resp. H. Alencar, M. P. do Carmo and A. G. Colares [Math. Z. 213, 117-131 (1993; Zbl 0792.53057)]. They use variational properties of functions of the mean curvatures derived by R. C. Reilly [J. Differ. Geom. 8, 465-477 (1973; Zbl 0277.53030)].
### MSC:
53C42 Differential geometry of immersions (minimal, prescribed curvature, tight, etc.) 49K10 Optimality conditions for free problems in two or more independent variables 53A10 Minimal surfaces in differential geometry, surfaces with prescribed mean curvature
### Citations:
Zbl 0653.53045; Zbl 0816.53031; Zbl 0792.53057; Zbl 0277.53030
Full Text:
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2022-07-05 01:01:31
|
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|
https://tex.stackexchange.com/questions/581394/opacity-does-not-work-on-first-page
|
# Opacity does not work on first page
Look at this example:
%! TEX program = xelatex
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\usepackage{blindtext}
\begin{document}
{%
\begin{tikzpicture}[remember picture,overlay]
\draw[opacity=0.2] ($(current page.north east)+(-1cm,-1cm)$) -- ($(current page.south east)+(-1cm,1cm)$);
\end{tikzpicture}%
}
\blindtext[20]
\end{document}
It draws a vertical line with opacity 0.2 on the right side. However the opacity setting does not work on first page. It's similar to the example in this answer but the solution there does not work here.
If you add after your \AddToHook a \ShowHook{shipout/background} you will get
-> The hook 'shipout/background':
> Code chunks:
> pgfrcs -> \put (\hoffset -1in,\voffset -1in){\pgfutil@abe \unhbox \pgfutil@abb \pgfutil@abc \global \let \pgfutil@abc \pgfutil@empty }
> Document-level (top-level) code (executed last):
> -> \begin {tikzpicture}[remember picture,overlay] \draw [opacity=0.2] ($(current page.north east)+(-1cm,-1cm)$) -- ($(current page.south east)+(-1cm,1cm)$); \end {tikzpicture}
The pgfrcs chunk is from tikz/pgf and responsable for the opacity. But your code is later and so pgf doesn't catch it.
The problem will be resolved in future LaTeX versions, but for now you have to change the execution order yourself by giving your code a label and using a rule to change the order:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\usepackage{blindtext}
\DeclareHookRule{shipout/background}{jinwen/opac}{before}{pgfrcs}
\begin{document}
{%
\begin{tikzpicture}[remember picture,overlay]
\draw[opacity=0.2] ($(current page.north east)+(-1cm,-1cm)$) -- ($(current page.south east)+(-1cm,1cm)$);
\end{tikzpicture}%
}
%\ShowHook{shipout/background}
\blindtext[20]
\end{document}
• Thanks for this! By the way, I also noticed that \shade ... is not being drawn on the first page. How could one fix this? Feb 1 '21 at 10:42
• show an example, at best in a new question. Feb 1 '21 at 11:00
• I just proposed a new question. Feb 1 '21 at 11:05
You can also use a savebox, but you can't use [remember picture] as every \usebox will add the same pgfid to the aux file. OTOH, \put(0pt,0pt) corresponds to (current page.north west) and \put(\paperwidth,-\paperheight) to (current page.south east), etc. so you don't really need it. Nor do you get the aux file delay.
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\newsavebox{\mybackground}
\savebox{\mybackground}{\begin{tikzpicture}[baseline=(origin)]
\coordinate (origin) at (0,0);
\draw[opacity=0.2] (\paperwidth-1cm, -1cm) -- (1cm, 1cm-\paperheight);
\end{tikzpicture}}
\usepackage{blindtext}
\begin{document}
|
2022-01-18 15:37:47
|
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|
http://crypto.stackexchange.com/questions?page=4&sort=votes&pagesize=30
|
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2015-07-28 15:29:52
|
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|
http://tex.stackexchange.com/questions/151927/reverse-citation-order-of-two-library-entries
|
# Reverse citation order of two library entries
I have the following problem illustrated by a simple example: If I cite the paper of an author T. Coven in my document, the outcome is 'Coven (2004b)'. If I cite the appendix to this paper, the outcome is 'Coven (2004a)'. Now the appendix pops up much less frequently than the original paper, therefore I would like to reverse the order (exchange 'a' and 'b' in the citations). Is this possible?
I am using Biblatex. Here is the bib-file of the above example (named: lib.bib):
@article{co:2004,
author = {T. Coven},
title = {Title A},
journaltitle = {The X Journal},
date = {2004}
}
@article{coapp:2004,
author = {T. Coven},
title = {Appendix to Title A},
journaltitle = {The X Journal},
date = {2004}
}
MWE:
\documentclass[a4paper, 12pt, headsepline, headings=small,]{scrreprt}
\usepackage[backend=bibtex8,
style=authoryear-icomp,
dashed=false,
autocite=footnote,
maxcitenames=3,
mincitenames=1,
maxbibnames=100,
firstinits=true,
sorting=nty
]{biblatex}
\bibliography{lib}
\begin{document}
\cite{co:2004} and \cite{coapp:2004}
\end{document}
-
## 2 Answers
Well, you will have to adjust the sorting manually by providing some sort of sort... field for biblatex, so it knows how to sort the entries.
You use a authoryear style, but a nty sorting ("name-title-year" sorting), that seems odd. If you want to stick with it, go with the sorttitle field and do something like
@article{coapp:2004,
author = {T. Coven},
title = {Appendix to Title A},
journaltitle = {The X Journal},
date = {2004},
sorttitle = {Title A/Appendix},
}
MWE
\documentclass[a4paper, 12pt, headsepline, headings=small,]{scrreprt}
\usepackage{filecontents}
\usepackage[backend=biber,
style=authoryear-icomp,
dashed=false,
autocite=footnote,
maxcitenames=3,
mincitenames=1,
maxbibnames=100,
firstinits=true,
sorting=nty,
]{biblatex}
\begin{filecontents*}{\jobname.bib}
@article{co:2004,
author = {T. Coven},
title = {Title A},
journaltitle = {The X Journal},
date = {2004},
}
@article{coapp:2004,
author = {T. Coven},
title = {Appendix to Title A},
journaltitle = {The X Journal},
date = {2004},
sorttitle = {Title A/Appendix},
}
\end{filecontents*}
\addbibresource{\jobname.bib}
\begin{document}
\nocite{co:2004,coapp:2004}
\printbibliography
\end{document}
A more natural sorting choice for a Author-Year style would be sorting=nyt or even sorting=nyvt (sorting by "name-year-title" and "name-year-volume-title" respectively). In that case you could go with
@article{co:2004,
author = {T. Coven},
title = {Title A},
journaltitle = {The X Journal},
date = {2004},
sortyear = {2004-1},
}
@article{coapp:2004,
author = {T. Coven},
title = {Appendix to Title A},
journaltitle = {The X Journal},
date = {2004},
sortyear = {2004-2},
}
or (thanks again to lockstep)
@article{co:2004,
author = {T. Coven},
title = {Title A},
journaltitle = {The X Journal},
date = {2004},
}
@article{coapp:2004,
author = {T. Coven},
title = {Appendix to Title A},
journaltitle = {The X Journal},
date = {2004},
sortyear = {2004/1},
}
MWE
\documentclass[a4paper, 12pt, headsepline, headings=small,]{scrreprt}
\usepackage{filecontents}
\usepackage[backend=biber,
style=authoryear-icomp,
dashed=false,
autocite=footnote,
maxcitenames=3,
mincitenames=1,
maxbibnames=100,
firstinits=true,
sorting=nyt,
]{biblatex}
\begin{filecontents*}{\jobname.bib}
@article{co:2004,
author = {T. Coven},
title = {Title A},
journaltitle = {The X Journal},
date = {2004-1},
}
@article{coapp:2004,
author = {T. Coven},
title = {Appendix to Title A},
journaltitle = {The X Journal},
date = {2004},
sortyear = {2004-2},
}
\end{filecontents*}
\addbibresource{\jobname.bib}
\begin{document}
\nocite{co:2004,coapp:2004}
\printbibliography
\end{document}
Both methods yield
-
nice, thanks. Exactly what I needed. I will follow the second suggestion that you have made, using sorting=nyvt. – TomM Dec 31 '13 at 14:15
+1. However, the OP uses backend=bibtex8, which will result in an incorrectly sorted bibliography with sorttitle = {Title A, Appendix}. For the correct result, use sorttitle = {Title A/Appendix}. – lockstep Dec 31 '13 at 14:17
@lockstep Nice to know. Thanks for the heads-up. – moewe Dec 31 '13 at 14:18
I just noticed the solution for sorting=nyvt doesn't work, maybe also because of backend=bibtex8? – TomM Dec 31 '13 at 14:23
@TomM That's all this 32/64 bit business for you. But as noted there, you can install the 32 bit version even if you do use the 64 bit MikTeX. – moewe Dec 31 '13 at 15:04
Use the sorttitle field. See section 2.2.3 of the biblatex manual for details.
\documentclass{article}
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@article{co:2004,
author = {T. Coven},
title = {Title A},
journaltitle = {The X Journal},
date = {2004}
}
@article{coapp:2004,
author = {T. Coven},
title = {Appendix to Title A},
sorttitle = {Title A/Appendix},
journaltitle = {The X Journal},
date = {2004}
}
\end{filecontents}
\usepackage[backend=bibtex8,
style=authoryear-icomp,
dashed=false,
sorting=nty
]{biblatex}
\addbibresource{\jobname.bib}
\begin{document}
\cite{co:2004} and \cite{coapp:2004}
\printbibliography
\end{document}
-
|
2014-09-30 21:59:51
|
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|
https://projecteuclid.org/euclid.jsl/1183745525
|
## Journal of Symbolic Logic
### Relational Semantics and a Relational Proof System for Full Lambek Calculus
Wendy MacCaull
#### Abstract
In this paper we give relational semantics and an accompanying relational proof theory for full Lambek calculus (a sequent calculus which we denote by FL). We start with the Kripke semantics for FL as discussed in [11] and develop a second Kripke-style semantics, RelKripke semantics, as a bridge to relational semantics. The RelKripke semantics consists of a set with two distinguished elements, two ternary relations and a list of conditions on the relations. It is accompanied by a Kripke-style valuation system analogous to that in [11]. Soundness and completeness theorems with respect to FL hold for RelKripke models. Then, in the spirit of the work of Orlowska [14], [15], and Buszkowski and Orlowska [3], we develop relational logic RFL. The adjective relational is used to emphasize the fact that RFL has a semantics wherein formulas are interpreted as relations. We prove that a sequent $\Gamma \rightarrow \alpha$ in FL is provable if and only if a translation, t($\gamma_1 \bullet \cdots \bullet \gamma_n \supset \alpha)\varepsilon \upsilon u$, has a cut-complete fundamental proof tree. This result is constructive: that is, if a cut-complete proof tree for $t(\gamma_1 \bullet \cdots \bullet \gamma_n \supset \alpha)\varepsilon \upsilon u$ is not fundamental, we can use the failed proof search to build a relational countermodel for $t(\gamma_1 \bullet \cdots \bullet \gamma_n \supset \alpha)\varepsilon \upsilon u$ and from this, build a RelKripke countermodel for $\gamma_1 \bullet \cdots \bullet \gamma_n \supset \alpha$. These results allow us to add FL, the basic substructural logic, to the list of those logies of importance in computer science with a relational proof theory.
#### Article information
Source
J. Symbolic Logic, Volume 63, Issue 2 (1998), 623-637.
Dates
First available in Project Euclid: 6 July 2007
https://projecteuclid.org/euclid.jsl/1183745525
Mathematical Reviews number (MathSciNet)
MR1625899
Zentralblatt MATH identifier
0926.03024
JSTOR
|
2019-10-19 18:53:58
|
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|
http://clay6.com/qa/126164/a-real-valued-function-f-x-satisfies-the-functional-equation-f-x-y-f-x-f-y-
|
# A real valued function $f(x)$ satisfies the functional equation $f(x-y) = f(x) f(y) - f(a-x) f(a+y)$ where $a$ is a given constant and $f(0) = 1, f(2a - x)$ is equal to :
( A ) $f(a) + f(a-x)$
( B ) $-f(x)$
( C ) $f(x)$
( D ) $-f(x)$
|
2019-03-20 05:46:15
|
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|
https://mathoverflow.net/questions/353740/singular-schemes-with-a-torus-action-and-embedded-points
|
# Singular schemes with a torus action and embedded points
I've got a couple rather geometric questions about the following setup.
Let $$X$$ be a scheme over an algebraically closed field ($$\mathbb{C}$$, say) with the action of a torus $$T$$, such that the action has finitely many fixed points. $$X$$ may have some mild singularities but is normal, Cohen-Macaulay, etc. Let $$\mathscr{L}$$ be a $$T$$-equivariant line bundle on $$X$$.
We can form the $$T$$-fixed subscheme $$X^T$$. In general, the $$\mathbb{C}$$ points of $$X^T$$ will be some discrete set, but $$X^T$$ need not be reduced, so we should think of $$X^T$$ as some nonreduced scheme supported at some finite set of points.
Furthermore, let me consider a rational curve $$Y \hookrightarrow X$$, stable under the $$T$$ action, joining two $$T$$-fixed points $$p_1$$ and $$p_2$$ in $$X$$. If I assume that $$Z$$, the component of $$X^T$$ supported at $$p_2$$, is nonreduced, I could consider the scheme $$Y'=Y \cup_{p_2} Z$$ (I am not sure exactly how to make this more precise: do I want a pushout of these two schemes?).
Question 1: In the above setup, am I justified in viewing this scheme $$Y'$$ as $$Y$$ along with some embedded points (corresponding to the non-reduced points over $$p_2$$)?
Question 2: Let $$I$$ be the ideal sheaf of $$X^T$$ in $$X$$. Assume that I know how $$\mathscr{L}$$ restricts to $$Y$$; $$\mathscr{L}|_Y=\mathscr{O}_{\mathbb{P}^1}(n)$$, say.
Now consider the restriction $$(I \otimes \mathscr{L})|_{Y}$$. The sections of this sheaf over $$Y$$ will be some subset of $$\Gamma(Y,\mathscr{O}_Y(n))$$, vanishing at the $$T$$-fixed points $$p_1$$ and $$p_2$$. Note moreover that $$I \otimes \mathscr{L}|_Z=0$$, since $$I$$ vanishes identically on the $$T$$-fixed locus. My question is, do I gain information about orders of vanishing of sections $$s \in \Gamma(Y, (I \otimes \mathscr{L})|_Y)$$ at $$p_2$$?
In other words, if a section vanishes at an embedded point of the curve, can I see that reflected in higher orders of vanishing of that section restricted to the closed points of the curve?
I'm happy to expand or clarify any bit of this (it's rather sketchy) and would be nearly as happy with a good reference as a direct answer.
|
2022-05-28 16:21:03
|
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|
http://mathematica.stackexchange.com/questions?page=215&sort=newest
|
# All Questions
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### How to apply a conformal map to a jpg (or other image)
I would like to apply a conformal map to a jpg. For example, the map $z\mapsto z^2$ to this image: http://thumbs3.ebaystatic.com/d/l225/m/mGyeriV7l-YArkeBd9oMUng.jpg Any help on how to do this?
|
2015-04-21 11:46:18
|
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|
http://mathhelpforum.com/discrete-math/205688-cauchy-sequence.html
|
# Math Help - Cauchy Sequence
1. ## Cauchy Sequence
I need to prove that every Cauchy sequence is bounded. Here is my work thus far:
{a(sub n)}n=1 to infinity is a Cauchy sequence. A sequence is said to be Cauchy if for all E>0 there exists N in the natural numbers such that if m,n>=N, then |a(sub n)-a (sub m)|<E.
Proof: Let E=1. Then there exists N in the natural numbers such that m,n>=N implies that |a(sub n)-a(sub m)|<1. By the reverse triangle inequality, ||a(sub n)|-|a(sub m)||<=|a(sub n)-a(sub m)|<1 for m,n>=N, so |a(sub n)|<=|a(sub N+1)|+1 for n>=N. (Fix m=N+1). Let M=max{|a(sub 1)|, |a(sub 2)|, ..., |a(sub N+1)|+1} then |a(sub n)|<=M.
Can you tell me if I am missing any information?
2. ## Re: Cauchy Sequence
Originally Posted by lovesmath
I need to prove that every Cauchy sequence is bounded.
Because this may well be a most important theorem in sequences, I think its proof needs to done correctly.
$1>0$ so $\exists N$ such that if $n\ge N$ then $|a_n-a_N|<1$
Of course that means $|a_n|\le 1+|a_N|$ if $n\ge N$
Let $B = 1 + \sum\limits_{k = 1}^N {|a_k |}$.
Thus $|a_n|\le B$ for $\forall n~.$
|
2014-09-22 01:18:12
|
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|
https://www.math.gatech.edu/seminars-colloquia/series/geometry-topology-student-seminar/jamie-conway-20130213
|
## Hyperbolicity of the Arc and Curve Complex
Series:
Geometry Topology Student Seminar
Wednesday, February 13, 2013 - 13:00
1 hour (actually 50 minutes)
Location:
Skiles 005
,
Georgia Tech
Organizer:
Given any surface, we can construct its curve complex by considering isotopy classes of curves on the surface. If the surface has boundary, we can construct its arc complex similarly, with isotopy clasess of arcs, with endpoints on the boundary. In 1999, Masur and Minsky proved that these complexes are hyperbolic, but the proof is long and involved. This talk will discuss a short proof of the hyperbolicity of the curve and arc complex recently given by Hensel, Przytycki, and Webb.
|
2018-05-27 21:54:51
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https://www.transtutors.com/questions/alan-is-an-employee-at-abc-pty-ltd-abc-he-has-negotiated-the-following-remuneration--748800.htm
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# Alan is an employee at ABC Pty Ltd (ABC). He has negotiated the following remuneration package... 1 answer below »
Alan is an employee at ABC Pty Ltd (ABC). He has negotiated the following remuneration package with ABC: • salary of $300,000; • Payment of Alan's mobile phone bill ($220 per month, including GST). Alan is under a two-year contract whereby he is required to pay a fixed sum each month for unlimited usage of his phone. Alan uses the phone for work-related purposes only; • Payment of Alan's children's school fees ($20,000 per year). The school fees are GST free. ABC also provided Alan with the latest mobile phone handset, which cost$2,000 (including GST). At the end of the year ABC hosted a dinner at a local Thai restaurant for all 20 employees and their partners. The total cost of the dinner was \$6,600 including GST. (a) Advise ABC of its FBT consequences arising out of the above information, including calculation of any FBT liability, for the year ending 31 March 2014. Assume that ABC would be entitled to input tax credits in relation to any GST-inclusive acquisitions. (b) How would your answer to (a) differ if ABC only had 5 employees? (c) How would your answer to (a) differ if clients of ABC also attended the end-of-year dinner?
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2020-02-22 10:31:49
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http://www.quantumforest.com/2012/10/scraping-pages-and-downloading-files-using-r/
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I have written a few posts discussing descriptive analyses of evaluation of National Standards for New Zealand primary schools.The data for roughly half of the schools was made available by the media, but the full version of the dataset is provided in a single-school basis. In the page for a given school there may be link to a PDF file with the information on standards sent by the school to the Ministry of Education.
I’d like to keep a copy of the PDF reports for all the schools for which I do not have performance information, so I decided to write an R script to download just over 1,000 PDF files. Once I can identify all the schools with missing information I just loop over the list, using the fact that all URL for the school pages start with the same prefix. I download the page, look for the name of the PDF file and then download the PDF file, which is named school_schoolnumber.pdf. And that’s it.
Of course life would be a lot simpler if the Ministry of Education made the information available in a usable form for analysis.
library(XML) # HTML processing
options(stringsAsFactors = FALSE)
# Base URL
base.url = 'http://www.educationcounts.govt.nz/find-a-school/school/national?school='
# Schools directory
directory <- subset(directory,
!(school.type %in% c("Secondary (Year 9-15)", "Secondary (Year 11-15)")))
# Reading file obtained from stuff.co.nz obtained from here:
# http://schoolreport.stuff.co.nz/index.html
# Defining schools with missing information
to.get <- merge(directory, fairfax, by = 'school.id', all.x = TRUE)
# Looping over schools, to find name of PDF file
for(school in to.get\$school.id){
cat('Processing school ', school, '\n')
doc.html <- htmlParse(paste(base.url, school, sep = ''))
if(length(pdf.url) > 0) {
}
}
## Can you help?
It would be great if you can help me to get the information from the reports. The following link randomly chooses a school, click on the “National Standards” tab and open the PDF file.
Then type the achievement numbers for reading, writing and mathematics in this Google Spreadsheet. No need to worry about different values per sex or ethnicity; the total values will do.
Gratuitous picture: a simple summer lunch (Photo: Luis).
1. Very creative way of getting things done
2. Could be a job for Amazon’s Mechanical Turk?
• It could, but this is a hobby and I’m hoping that people will participate.
• Yes, we’ll have to get add up all the numbers and then get the proportions. Interesting reports, with traffic light colors and using Comic Sans.
Thanks for the support; it seems to be such a divisive issue!
• No because the documents do not follow a preset format. One has to read it to know where are the relevant numbers. In addition, some of them are text documents while others are images.
3. The was a useful example of practical data analysis for me, especially the political and technical issues with the underlying data. I strung them together in RStudio as a reproducible report – that’s the nature of reporting in education.
The reply from a teacher was a lesson too: the complex information encoded in an overall grade or assessment, both subjective observations and objective test data.
Starting data analysis from that point might produce analyses which the would embrace, e.g. supplying the kind of ‘spreadsheet’ teachers are compelled to construct for themselves to record grading information. That might support reproducible reporting locally within schools, not just nationally.
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2013-05-23 17:15:58
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https://mathshistory.st-andrews.ac.uk/Extras/Hewitt_autobiography/
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# Edwin Hewitt autobiography
Edwin Hewitt wrote So Far, So Good: My Life Up to Now in 1988, two years after he retired, giving details of his life. Sadly he suffered a severe stroke in January 1989. We give a version of Hewitt's article below.
So Good: My Life Up to Now, by Edwin Hewitt
I was born in Everett, Washington (USA) on 20 January 1920. I am the youngest of three children born to Irenaeus Prime Hewitt and Margaret Guthrie Hewitt. I had two siblings: William Guthrie Hewitt (1916- 1983) and Helen Hewitt Arthur (1918-1953). Our parents were old American stock. On my father's side we (and myriad other Hewitts) are descended from Thomas Hewitt, who flourished, as the saying goes, in North Stonington, Connecticut, in 1639. On my mother's side there are a lot of Pennsylvania Dutch ancestors, some with a wild streak that keeps cropping up unto the third and fourth generation. My father was trained as a lawyer, but in my lifetime never practiced law. My mother had a bachelor's degree in English from the University of Nebraska. During my first decade she was a housewife, but also taught English as a freelance and for two years studied English in the graduate school of the University of Washington.
My early memories are for the most part happy, though I carry to this day recollections of stern discipline meted out for this or that childish crime. I suppose I was precocious, though by no means a prodigy. An early memory is of being taken to a meeting of the Everett Rotary Club and being stood up on a table to recite the Gettysburg Address. My mother began to teach all three of her children French, using a little book called French without Tears. I can still quote passages from that little book, and recite the Gettysburg address.
I was an insufferable child. I had - and still suffer from - a terrible habit of mouthing off. Recognising this weakness has at least preserved me from the folly of becoming a department chairman or dean: I knew that at some inopportune moment I would lose control of my tongue and then lose my job.
My mother was devoted to literature. During summer vacations in the 1920s, she and her children read aloud to each other Pilgrims Progress, David Copperfield, Dombey and Son, Oliver Twist, and finally Vanity Fair. I recall my pride at being given the honour of reading the last instalment of Vanity Fair to my mother and siblings.
In 1931, my mother took all three of her children to St. Louis, Missouri, where she enrolled us in the Principia Academy, a Christian Science school. I have no idea where she got the money, I know now that she was determined to get out of Everett, Washington, and away from my father. I spent three academic years at Principia and two at a Christian Science country boarding school called The Leelanau School, located 30 miles west of Traverse City, Michigan. I got a good education at both schools, though I had unhappy times at both. Part of the process of growing up, no doubt.
I entered Harvard in 1936 on a Samuel Crocker Lawrence scholarship in the amount of $500 per annum. A half-century ago Harvard charged$400 per annum tuition and $100 per annum for dormitory rooms [at least for the needy among us]. With waiting on tables for my meals and savings from summer jobs, I had no money problems. My six years at Harvard were happy. I melted into the crowd, no longer an underage, undersized misfit. The mathematics faculty was awe-inspiring. George David Birkhoff, an Olympian figure, was also dean of the Faculty of Arts and Sciences. William Caspar Graustein was a dignified man who always wore black three-piece suits. Edward Vermilye Huntington was an elderly scholar, plainly not part of the power structure. Joseph Leonard Walsh was greatly respected for his flawless lectures, though not for the Walsh- Rademacher functions: we had not heard of them. The younger faculty included David Vernon Widder, Saunders Mac Lane, Garrett Birkhoff, Willard van Orman Quine [I think he was in the Philosophy Department: he gave brilliant courses on mathematical logic], and Marshall Harvey Stone. In the autumn of 1937, Stone accepted me as an advisee. Thirty-four years of age and an associate professor [shortly thereafter promoted], he was at the meridian height of his mathematical powers. He had the strongest mind I had ever encountered. He had written a huge and, to me, incomprehensible book; he was a son of the Chief Justice of the United States; his lectures were known for their clarity and vigour. I took but one course from Stone, the theory of functions of a real variable, in 1939-1940. This course put my feet on the path to becoming mathematician. The concepts set forth in this course have been with me for forty-nine years; some of them appear in the book that Karl Stromberg and I wrote. From Stone and his fellow mathematicians at Harvard, I learned vital lessons about our wonderful subject: Rule #1. Respect the profession. Rule #2. In case of doubt, see Rule #1. My studies under Stone's policy of benign indifference led me into set-theoretic topology, to the neglect of much else. In 1941 I proved my first theorem, If X is a metric space without isolated points, then X contains complementary dense subsets. Early in 1942, I lectured on this and related matters to the Harvard Colloquium, G D Birkhoff did me the honour of attending. At the end he asked, "Mr Hewitt, how much of this would you have without the axiom of choice?" I replied, "Nothing at all, Sir." With that, G D said something like "hump" and turned about to register his scorn at a whippersnapper who couldn't construct the things he was talking about. I got my Ph.D. in June 1942 for a theses on set-theoretic topology written under Professor Stone. Saunders Mac Lane read the manuscript and half way through found an unfortunate blunder. Luckily the lacuna could be filled. George Mackey got his Ph.D. the same day I got mine, also from Stone. Professor Stone has been a decisive influence in my life for over half a century. My debt to his is second only to that I owe my dear parents. It is a marvel that Stone took me as his protégé, and over the years increasingly as his friend. Military service loomed for all young men in my position at that time. Nonetheless, I accepted an instructorship at Harvard in June 1942 and taught there happily for six months. This was a carefree time. I was the assistant senior tutor at a Harvard house and so had free room and board. I had my first serious girlfriend, an eighteen-year old Radcliffe sophomore. (She dropped me early in 1943.) I found mathematics of consuming interest and rejoiced in learning mathematics and in discovering new facts. In January 1943 John M Harlan paid a visit to Harvard. He was a prominent New York lawyer who had been recruited by W Barton Leach to organise and run an Operations Research Section at the 8th Bomber Command in England. Someone, probably Oswald Veblen, had given Harlan my and Frank Stewart's names. Harlan offered us positions with his group. We thought for as long as thirty seconds before saying "yes," and in April 1943 found ourselves in High Wycombe, 30 miles outside of London. Harlan was a colonel, and there were perhaps two other commissioned officers in the group. The rest of us, some 40 in number, were civilian scientists. I was put onto the problem of defending B-17 and B-24 bombers against German fighter planes. Astonishingly, here was the B-17 with machine guns all over it and no doctrine whatever for gunners to aim by. I attended an RAF gunnery school, where a sensible and simple system was taught. I recomputed the RAF data for our ammunition and airspeeds, and added new rules to deal with head-on attacks, which the night-flying RAF did not have to cope with. My first job was to convince Col. Harlan that I had the right answers. He gave me a lawyer-like grilling. Once satisfied that I was right, he turned me loose. I got great assistance. Major George R Weinbrenner was a great help until he was shot down. (He cold-cocked a guard on a train in Germany, walked through France, and lived the life of Riley on the Riviera until US forces liberated him in 1944.) I had able assistance from Sergeant John S Jillson, whom I had known at Harvard. There was a superb draftsman named Bosch. Porter Henry, a New York journalist, joined us and performed prodigies. I went all over the 8th Bomber Command, lecturing to bomber crews and passing out skilfully written training literature from Porter Henry. I felt it necessary to fly and wound up with seven missions to Germany and France as a bombardier-gunner. In the late summer of 1944 I was rotated back to the USA. I spent some weeks with Saunders Mac Lane's Applied Mathematics Panel at Columbia University and about 1 January 1945 joined an Operations Research Section at the headquarters of the 20th Air Force in the Pentagon. I wanted nothing so much as to go to the Marianas and help bomb Japan, but I never got my orders. I learned 20 years later that my mother had telephoned a deputy secretary of the Navy and asked him not to let me be sent out a second time. Altogether, my two and a half years with the Air Force were the best times of my life up to now. I've been a fortunate fellow. I've climbed some nontrivial mountains. I've skied across Lapland. I've driven 165 miles per hour in a motor car. I've known some wonderful women, two of whom I married. But nothing else even comes close to hanging around the Air Force and getting rides in their beautiful machines. I was discharged in September 1945. Powerful forces were guiding my destiny - I suspect Veblen or Stone. At any rate, Henry Allen Moe of the Guggenheim Foundation awarded me out of the blue a$2500 fellowship for reconversion to civilian life. Though I was of two minds about taking up mathematics again and thought of having a whirl at law school, I took the money and with my beautiful young wife, Carol Blanchard Hewitt, went to Princeton for the year 1945-1946. There was a galaxy of eminences at the Institute for Advanced Study: Albert Einstein, Carl Ludwig Siegel, John von Neumann (who was around only part of the time) Hermann Weyl, Kurt Gödel, James W Alexander, Marston Morse. Richard Arens was Morse's assistant; Ernst Strauss, Einstein's. At Princeton University there were Wedderburn (a man of small stature, no longer young, who wore well-cut tweeds), H.P. Robertson, L P Eisenhart, Salomon Bochner, Ralph Fox, Emil Artin, Solomon Lefschetz, Claude Chevalley. I was very much an Unterspieler but enjoyed watching the big shots, attending their seminars, and observing their foibles. I was horrified one day to watch Chevalley bait Weyl like a terrier nipping at a water buffalo, while Weyl was trying to give a lecture on Lie groups.
My own research paid off quickly, though of course with the usual struggles. I solved tow old problems posed by Paul Urysohn in the 1920s and discovered what are now called realcompact or Hewitt spaces. This came about through my efforts to understand the ring of all real-valued continuous [not necessarily bounded] functions on a completely regular T0-space. I was guided in part by a casual remark made by Gel'fand and Kolmogorov (Doklady Akad. Nauk SSSR 22 [1939], 11-15). Along the way I found a novel class of real-closed fields that superficially resemble the real number field and have since become the building blocks for nonstandard analysis. I had no luck in talking to Artin about these hyperreal fields, though he had done interesting work on real-closed fields in the 1920s. (My published "proof" that hyperreal fields are real-closed is false: John Isbell earned my gratitude by giving a correct proof some years later.) In fact, what I got from Artin was a quick brush-off. My ultra-filters also struck no responsive chords. Only Irving Kaplansky seemed to think my ideas had merit. My first paper on the subject was published only in 1948. It got a lukewarm review from Dieudonné. Later Leonard Gillman, Meyer Jerison, and Melvin Henriksen put me under a great debt by taking the matter up afresh and doing a whole lot with rings of continuous functions. A lost of citations published a few years back by Joseph Schatz lists my 1948 paper as one of the most cited papers of the past fifty years. Three Soviet mathematicians came to the hyperreal field problem many years later: the hugely talented brothers Gregory and David Chudnovsky and that great fellow Misha Antonoviskij. The four of us published a joint paper in 1983 on rings of continuous functions. Nothing like coming back to a problem after 35 years!
In 1946-1947, I taught at Bryn Mawr College. I was not housebroken enough for Bryn Mawr. Although John Oxtoby and Anna Pell Wheeler were wonderful to me and expressed regret at my departure after one year, they must have felt relieved to have this loose cannon out of their pleasant demesne. I made friends among students at Bryn Mawr whom, 42 years later, I still cherish as my close friends.
I went to the University of Chicago in 1947 to take a half-time position with a military research project called CHORE [Chicago Ordnance Research] and a half-time position with the Department of Mathematics at the University of Chicago. This move was a disaster. I lost the military job by running afoul of the regular army colonel, Frank Fenton Reed, who was the Army liaison officer. I then found that Marshall Stone had no interest whatever in hiring me full time in his department. The man in charge of CHORE, Dean Walter Bartky, was decent enough about my plight but could do nothing to mitigate it. So I served out my one-year appointment in wretched circumstances.
In the spring of 1948, I generated job offers from two large midwestern universities and from the University of Washington. All salaries offered were \$4250 for the academic year. One of the Midwest schools offered me twelve hours per week of teaching: four sections of beginning calculus. The other Midwest school is in an agricultural state. I had enough Harvard snobbery to refuse to go where I thought I would be in the middle of cornfield.
The University of Washington offered a nine-hour teaching load, a course in the theory of functions of a complex variable, and the opportunity of living in Seattle, which I remembered pleasantly from my childhood. So in August 1948 my young wife and I, with most of our worldly goods in a station wagon and accompanied by my recently widowed father, set out for the Pacific Northwest.
I was taken with Seattle. We were welcomed by old friends from the 1920s, now rather grey at the temples. We found reasonable living accommodations. The department was a comfortable little group, which was for the most part unconcerned with research. Professors Z W Birnbaum (a Polish-born statistician), Ross A Beamont, and Herbert S Zuckerman rapidly became good friends. In particular, I found in Zuckerman a wonderful friend and collaborator. I learned most of my classical mathematics from him, a side that I had foolishly neglected in order to follow the sirens of functional analysis and set-theoretic topology. Herbert and I worked together from the autumn of 1948 until the day of his tragic and untimely death in June 1970. I am proud that my name stands alongside his, attached to now classical theorems in Diophantine approximation, the structure of semigroups, and abstract harmonic analysis.
In 1950 I attended the International Congress of Mathematicians at Harvard and met the great Swedish mathematician Arne Beurling. I had studied his enigmatic 1938 paper on the convolution algebra of functions of finite variation on the real line and asked him some questions about his proofs. Within minutes he invited me to spend a year with him in Uppsala. So my wife and I set about learning Swedish. In August 1951 we sailed for Copenhagen on the M S Stockholm. We had a splendid year in Sweden, though my hopes of achieving great things in research with Beurling never came to fruition. We made friends in Sweden who are today still close friends at the houseguest level. I can carry on a conversation in Sweden and read Dagens Nyheter.
In the summer of 1952 my wife was pregnant with our first daughter, Greta. We travelled in Germany, the Netherlands, France, Switzerland, and Britain. We met many interesting people, among them Wilhelm Blaschke, E Witt (who pointed out that I nearly stole his name, Hel Braun (who was a close friend up to her death), Helmut and Irma Grunsky (also lifelong friends), M. Plancherel (who gave me Kirschwasser in his garden in Züruch), Jean Dieudonné (who entertained me and others lavishly in Nancy), and Henri Cartan. We spent several weeks in Paris as guests of the late Leonard Jimmy Savage and his charming wife and young son Sam. They had an enormous apartment not far from La Santé. Jimmy and I did much of the research for our paper on product measures while sitting on a bench in the Luxemburg gardens, surrounded by nursemaids with prams. This paper contains the Hewitt-Savage 0-1 law, along with a construction of measures on extreme points of a convex set that is a special case of what later became Choquet theory.
Back in Seattle in the autumn of 1952 and settled down to a quiet life, I found myself picking up doctoral students. I was enthusiastic about mathematics; I gave lectures that were attention-getters though not show-stoppers; and over the years, a number of fine young men and women came to me for guidance as they worked toward the doctorate. The first was George H Swift (1954), who now is one of my best friends. Thirty-six others followed George over the years. Some have vanished to my sorrow. Many hold positions of great influence and trust in academe and industry. One has even been a university president: Albert J Froderberg. With Karl Stromberg and Kenneth Ross I have written many papers and three books. I am grateful to these fine scientists and good friends. It was seldom easy to work with me. Wis Comfort has maintained close ties of friendship as he has mounted to the academic empyrean. Leonard Yap, now a senior member of the faculty at the National University of Singapore, has been a stalwart friend. Those whom I don't list will forgive me. They know that I love them all and that I rejoice in their successes and mourn their misfortunes: and there are far more of the former than the latter.
I took the academic year 1972-1973 at the University of Texas in Austin, intending to stay permanently. There too I had many dear friends, but I missed the rain in Seattle, and I missed my Seattle friends. After spending the summer of 1973 in Russia with Greta and her younger sister Lise, I went back to the University of Washington. Lise majored in Russian at Middlebury, has a master's degree in Russian, and is now a professional translator of Russian into English.
I spent the years 1973-1975 as vice-chairman and chairman of the University of Washington Faculty Senate. This was good sport but of negative value to my career as a mathematician. I took a lot of unpopular positions, presented honestly the faculty's point of view, and once got on the AP wire with a rash statement about not hounding faculty for overdue library books. The fact is, of course, that the faculty have no power in running the university. We're hired help without a union to help us. The occasional star gets exceptional treatment from the administration, especially if he is a surgeon with a large team and a large budget. But the hard-eyed businessmen who run the university are not really interested in research as such or even in teaching. Naturally they like intercollegiate football. What they are mainly enamoured of is garnering government contracts and trafficking in real estate.
My great friend Heinz Bauer of the University of Erlangen-Nürnberg put me in for an Alexander von Humboldt-Stiftung prize. Through his efforts I was awarded one of these marvellous prizes. With it I spent the months September 1975-April 1976 and September 1986-December 1986 at the University of Erlangen and the University of Passau. To live in West Germany was a superb experience. I love the country, and I love the language [which I learned in 1938-1940]; and I am - or was in 1975 - fascinated by the Wehrmacht's and the Luftwaffe's performance in World War II. In Erlangen I quickly met Gunter Ritter, a Ph.D. student of Bauer who was assigned the care and feeding of this eccentric American. Ritter and I hit it off at once. Over the past thirteen years we have written four or five substantial joint papers, and the Ritters have spent many months in Seattle.
In 1982 I taught for a semester at the University of Alaska in Fairbanks. This was a great adventure with good colleagues and interesting students at a fine university in a burgeoning state. The following year I accepted a permanent appointment at Fairbanks but at the last moment reneged. My friends were justifiably chagrined and angry. When the oil market collapsed a year later, they must have been relieved not to have an additional tenured professor to support. I continue to treasure my Fairbanks friends, in particular Jack Distad and Bill Phillips.
I've been abundantly blessed for many years by attracting gifted collaborators. I've already mentioned a number of them. Let me list some others. The great analyst and great gentleman Kôsaku Yosida spent 1950-1951 at the University of Washington under the auspices of our chairman, Roy M Winger. Yosida and I wrote a paper on finitely additive measures that is still well regarded. In Princeton in 1956 I ran into E P Wigner at a party given by Kees Gugelot and wrote a paper with him at the party. Shizuo Kakutani and I have written two papers about measures on groups. One of these includes the first construction of what are now called Kronecker sets, which are remarkable sets in topological groups.
I had the privilege of writing a paper with I I Hirschman, Jr, on Fourier transforms on groups and a paper with John H Williamson on Dirichlet series. Both collaborations gave me a lot of pleasure.
A casual remark made in Moscow to Dusa McDuff led to a paper with her in Mat. Sbornik that has not received the attention it deserves. It shows that M(G) for an infinite compact non-Abelian group G can have infinite-dimensional simple homomorphic images: a startling result in view of the docile behaviour of M(G).
Robert Edwards, who now leads a secluded life in Canberra, has been a good friend since 1952. We have collaborated frequently, with Robert applying his great powers to whatever problem is at hand.
Gavin Brown of the University of New South Wales has taught me a lot of classical analysis and neoclassical analysis on groups. Our labours have resulted in three papers.
Shozo Koshi of the University of Hokkaido is the hardest worker I've ever met. We have collaborated happily on two papers.
My final Ph.D. student, Nakhlé Asmar, with unrivalled generosity asked me to be his co-author on what is really his work, the last item in my bibliography.
Teaching has been a vital part of my career. I love to get in front of a class or a colloquium audience - any audience, in fact. Professor Stone will forgive me for quoting one of his great aphorisms: "Teaching is a form of public entertainment, much like acting, which it closely resembles."
In 1984-1986 I taught a two-year honours analysis class at the University of Washington. These splendid young people were the best undergraduates I ever taught. I recall especially Eric Stromberg and Marrena Lindberg, who have extraordinary talents in several fields and are blessed with ebullient personalities. Nakhlé Asmar took his Ph.D. in 1986. I knew that I would never again get students like these. I found that I could feather my nest nicely by taking partial retirement in 1986. [Did you hear about the chap who always gave his parties in the basement? He liked to nether his fest.] Other straws in the wind whispered plainly that it was time to go. And so I retired on 1 July 1986.
Since then I've taught part-time at the University of Washington, travelled and lectured in eleven countries, and done a certain amount of research. I am learning Chinese.
In May 1988 my friends put on the HEWITTFEST.
Here I am, still having fun and grateful for every new experience. As my dear friend Ursula Leonhardt-von Barchewitz says Jeder Tag ist ein Geschenk.
Department of Mathematics
University of Washington
Seattle, WA 98195 USA
Last Updated January 2021
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2021-02-28 19:15:33
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https://socratic.org/questions/what-are-some-examples-of-igneous-rocks
|
# What are some examples of igneous rocks?
May 6, 2018
#### Answer:
Basalt from divergent boundaries
Granite from convergent boundaries.
#### Explanation:
igneous rocks come from the liquid mantle. Magma pours out from cracks in to the earth. The liquid magma hardeners into igneous rocks.
At divergent boundaries the earth cracks and allows magma to come to the surface due to an up rising convection current. The magma hardens into the igneous rock basalt.
At convergent boundaries one plate is pushed back down into the mantle. The plate ( usually an oceanic plate) is melted. The melted plate becomes igneous rocks. The melted material under pressure pushes up toward the surface of the earth. The magma that doesn't reach the surface hardens into granite. The magma that reaches the surface erupts in volcanos forming different forms of lava.
|
2019-07-20 00:48:16
|
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http://tex.stackexchange.com/questions/52640/sorting-comma-separated-lists-defined-with-or-without-macro
|
# Sorting Comma Separated Lists defined with, or without macro
I would like to be able to sort a comma separated list.
Before I resort to writing something that would require \ensureunix :-) and having that do the sort for me, I thought I'd make an attempt to doing it within TeX. So, with the help of the two questions listed in the references I have been able to get this to work, but only for the case where the list is not defined in a macro. Unfortunately for me, I only need the case where it works with macro defined lists, but would be nice to have one version which handles both.
1. With %\def\SupportMacroDefinedList{} commented out (as in the given MWE), you can see that the sorting works fine for the case when the list is not defined in a macro (right hand side of image). There are no spurious spaces and empty lists are handled just fine:
2. For the macro defined list (i.e., with \def\SupportMacroDefinedList{} uncommented), this is the best I can do:
This is labelled as "almost" working for several reasons, and note that there are different definitions of the list macros for each case. Some of the problems are:
• A trailing % was required after the first entry. Without that the sort order changes!!
• It does not properly handle empty lists (which the non-macro version above had no problems with).
• Multiple consecutive commas are properly treated as non-list members as in Zebra,,, but if there is a space in between the commas as in Zebra, , then this yields the error Undefined control sequence. <argument> \@xfor@endmarker.
• Similarly, can't have a line with just a comma (probably same issues as the spaces in multiple consecutive commas).
• This requires a trailing % after the last list member. Try taking that out, or adding a space before the % and making sense of the sort order.
## Notes:
• The commas in the output are printed at the end of each list member only to be able to see if there is any spurious spaces.
• According to the comments in How to process a comma separated list?, \clist_map_inline:nn is supposed to be able to strip spurious spaces, but does not seem to for me. Instead it treats the macro defined list as a single member list. Also, this same linked question references \clist_map_inline:on but this yields a compile time error: Undefined control sequence for me.
## Minimum Requirements:
For this to useful for me, I really only need it to handle
1. Empty lists (only commas, spaces, and/or newlines),
2. No trailing , on the last list member:
\newcommand*{\ListMembers}{%
Odd,
Zebra,
Even,
Alpha
}%
3. with a trailing , on the last member:
\newcommand*{\ListMembers}{%
Odd,
Zebra,
Even,
Alpha,
}%
Something that did not use the expl3 syntax would be great too as then I would at least have have some hope of modifying it if it was ever needed. :-)
## Code:
%\def\SupportMacroDefinedList{}%
\documentclass{article}
\usepackage{datatool}
\usepackage{xparse}
\usepackage{xstring}
\newcommand*{\SortDBName}{sortDB}%
\newcommand*{\DBKey}{label}%
\newcommand{\TitleA}{\textit{My Enumerated List:}}%
\newcommand{\TitleB}{\textit{My Empty List:}}%
%------------------------------------- Sort CSV list
% http://tex.stackexchange.com/questions/40031/how-to-process-a-comma-separated-list
% http://tex.stackexchange.com/questions/6988/how-to-sort-an-alphanumeric-list
\newcommand{\SortItem}[1]{%
\IfStrEq{#1}{\empty}{%
% Skip empty list members
}{%
\DTLnewrow{\SortDBName}%
\IfEndWith{#1}{\space}{% attempt to remove any trailing space
\DTLnewdbentry{\SortDBName}{\DBKey}{\StrGobbleRight{#1}{1}}%
}{%
\DTLnewdbentry{\SortDBName}{\DBKey}{#1}%
}%
}%
}
% How do I make \SortCommaSeparatedList work for BOTH cases
\ifdefined\SupportMacroDefinedList%
\ExplSyntaxOn
\NewDocumentCommand{\SortCommaSeparatedList}{>{\SplitList {,}}m}
{ \clist_map_inline:Nn {#1} { \SortItem {##1} } }% List in macro
% Note: nn is supposed to handle spurious spaces as per ... but doesn't
\ExplSyntaxOff
\else
\ExplSyntaxOn
\NewDocumentCommand{\SortCommaSeparatedList}{>{\SplitList {,}}m}
{ \tl_map_inline:nn {#1} { \SortItem {##1} } }% Non macro list
\ExplSyntaxOff
\fi%
\newcommand{\SortedList}[3]{%
% #1 = type of list
% #2 = title to print
% #3 = list content (Comma separated list)
%
\noindent#2\par%
%
\DTLifdbexists{\SortDBName}%
{\DTLcleardb{\SortDBName}}% DB exists, so just clear it
{\DTLnewdb{\SortDBName}}% DB does not exist, so create it
%
\SortCommaSeparatedList{#3}%
\DTLsort{\DBKey}{\SortDBName}%
\IfEq{\DTLrowcount{\SortDBName}}{0}{%
\par%
No items to print for #1" list.%
}{%
\begin{#1}%
\DTLforeach*{\SortDBName}{\CurrentItem=\DBKey}{%
\item \CurrentItem,%
}%
\end{#1}%
}%
}%
\ifdefined\SupportMacroDefinedList%
\newcommand*{\ListMembers}{% Why is % required after the first line?
Odd,%
Zebra,
%,% Can't have this
Even,
Alpha%
}%
\newcommand*{\EmptyListMembers}{%
, ,% %%% Note: Spaces after last comma NOT-ok for macro version
}%
\else%
\newcommand*{\ListMembers}{%
Odd,,
Zebra, ,
,
Even,
Alpha ,
}%
\newcommand*{\EmptyListMembers}{%
, , % %%% Note: Spaces after last comma ok for non-macro version
}%
\fi%
\begin{document}
\ifdefined\SupportMacroDefinedList%
\section*{Almost works for Macro Defined List}%
\else%
\section*{Works for non-macro Defined List}%
\fi%
\begin{minipage}[t]{0.45\linewidth}\noindent%
\textbf{Macro defined list}\medskip\par%
\SortedList{enumerate}{\TitleA}{\ListMembers}
\SortedList{itemize}{\TitleB}{\EmptyListMembers}
\end{minipage}%
%
\hfill
%
\begin{minipage}[t]{0.45\linewidth}%
\textbf{Non-macro defined list}\medskip\par\noindent%
\SortedList{enumerate}{\TitleA}{ Odd, Zebra, , Even , Alpha ,}
\SortedList{itemize}{\TitleB}{ , , }
\end{minipage}%
\end{document}
-
There are many ways of tackling this problem: which you choose depends on your particular requirements.
Taking the example in the question, the reason for the apparent failure with \clist_map_inline:nn is that expl3 is very careful not to expand anything 'by accident'. Thus when the argument grabbed is a macro containing a comma-separated list, the code never sees the commas: for all you know this could be a list of one item only which just happens to be a macro itself containing a further list! There is also a difference in expl3 between functions which deal with 'stored' and 'inline' comma lists. Essentially, the idea is that a 'stored' list will already have been sanitized to remove spaces and empty items. So what you need to do is use the inline list function and expand your input once:
\NewDocumentCommand \SortCommaSeparatedList { m }
{ \exp_args:No \clist_map_function:nN {#1} \SortItem }
This will work with both forms of your input as your 'inline' list only contains unexpandable tokens. In general you cannot assume that, so I would say that \SortCommaSeparatedList should be described as accepting either a macro containing a list, or as accepting a list, but not both.
To avoid expl3, perhaps the easiest way would be to use LaTeX2e's \@for along with some space stripping code, again altering as little as possible:
\makeatletter
\newcommand*{\SortCommaSeparatedList}[1]{%
\expandafter\@for\expandafter\@tempa\expandafter:\expandafter=#1\do{%
\edef\@tempa{\expandafter\trim@spaces\expandafter{\@tempa}}%
\expandafter\SortItem\expandafter{\@tempa}%
}
}
% This is expl3's \tl_trim_spaces:n
\def\@tempa#1{%
\newcommand{\trim@spaces}[1]{%
\unexpanded\trim@spaces@aux@i\@mark##1\@nil\@mark#1{}\@mark
\trim@spaces@aux@ii\trim@spaces@aux@iii#1\@nil\trim@spaces@aux@iv\@stop
}
\newcommand{\trim@spaces@aux@i}{}
\long\def\trim@spaces@aux@i##1\@mark#1##2\@mark##3{%
##3%
\trim@spaces@aux@i\@mark##2\@mark#1{##1}%
}
\newcommand{\trim@spaces@aux@ii}{}
\long\def\trim@spaces@aux@ii##1\@mark\@mark##2{%
\trim@spaces@aux@iii##2%
}
\newcommand{\trim@spaces@aux@iii}{}
\long\def\trim@spaces@aux@iii##1#1\@nil##2{%
##2%
##1\@nil
\trim@spaces@aux@iii
}
\newcommand{\trim@spaces@aux@iv}{}
\long\def\trim@spaces@aux@iv##1\@nil##2\@stop{%
\expandafter{\@gobble##1}%
}
}
\@tempa{ }
\makeatother
This again expands the argument once, and this time we do a more awkward loop over every item. The space-trimming code is exactly that in expl3, but written in a more 'traditional' form. (You could write the loop more efficiently here by using that from expl3, but that seems like more effort for very little real gain.)
You could go further in a few ways. First, if you are willing to stick with expl3 then you could avoid loading xstring and do the comparisons using \tl_if_empty:nTF and so forth. There is also an experimental sorting module which would do the entire job for you! On the other hand, as expl3 requires the \pdfstrcmp primitive you could use that for the sort, although that will be slightly complicated as it works purely on character codes. Finally of course you could use LuaTeX, and do the sort in Lua (I guess that you want some reasonably general, so that is probably out).
-
The name \trim@spaces conflicts with the definition in the environ package. Should expl3 use a different name? – Peter Grill May 27 '12 at 7:19
@PeterGrill The expl3 version is called \tl_trim_spaces:n. I recoded it as \trim@spaces in the answer so that it can be used without loading expl3: any choice of name is possible here. – Joseph Wright May 27 '12 at 7:21
|
2014-08-01 04:07:58
|
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|
https://answers.ros.org/answers/121981/revisions/
|
Recently i found out that in the Gazego main window Edit menu are the resent commands (crt + r). Moreover, the Gazego node has a service /gazebo/reset_world does the same.
|
2022-05-19 22:47:28
|
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|
https://zenodo.org/record/3814723/export/xd
|
Software Open Access
# Nonlinear measures for dynamical systems
Schölzel, Christopher
### Dublin Core Export
<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
<dc:creator>Schölzel, Christopher</dc:creator>
<dc:date>2019-06-16</dc:date>
<dc:description>NOnLinear measures for Dynamical Systems (nolds)
Nolds is a small numpy-based library that provides an implementation and a learning resource for nonlinear measures for dynamical systems based on one-dimensional time series. Currently the following measures are implemented:
sample entropy (sampen)
Measures the complexity of a time-series, based on approximate entropy
correlation dimension (corr_dim)
A measure of the fractal dimension of a time series which is also related to complexity.
Lyapunov exponent (lyap_r, lyap_e)
Positive Lyapunov exponents indicate chaos and unpredictability. Nolds provides the algorithm of Rosenstein et al. (lyap_r) to estimate the largest Lyapunov exponent and the algorithm of Eckmann et al. (lyap_e) to estimate the whole spectrum of Lyapunov exponents.
Hurst exponent (hurst_rs)
The hurst exponent is a measure of the "long-term memory" of a time series. It can be used to determine whether the time series is more, less, or equally likely to increase if it has increased in previous steps. This property makes the Hurst exponent especially interesting for the analysis of stock data.
detrended fluctuation analysis (DFA) (dfa)
DFA measures the Hurst parameter H, which is very similar to the Hurst exponent. The main difference is that DFA can be used for non-stationary processes (whose mean and/or variance change over time).
Example
import nolds
import numpy as np
rwalk = np.cumsum(np.random.random(1000))
h = nolds.dfa(rwalk)
Requirements
Nolds supports Python 2 (>= 2.7) and 3 (>= 3.4) from one code source. It requires the package numpy.
These are the only hard requirements, but some functions will need other packages:
If you want to use the RANSAC algorithm for line fitting, you will also need the package sklearn.
For the true random numbers generated by nolds.qrandom you need the package quantumrandom.
The plotting functions in nolds.examples require the package matplotlib.
Installation
Nolds is available through PyPI and can be installed using pip:
pip install nolds
You can test your installation by running some sample code with:
python -m nolds.examples lyapunov-logistic
Alternatively, if you do not have matplotlib installed, you can run the unittests with:
python -m unittest nolds.test_measures
If you only have the download from this Zenodo publication available, you can unzip the archive and run the following command inside the folder:
python setup.py install
Documentation
Nolds is designed as a learning resource for the measures mentioned above. Therefore the corresponding functions feature extensive documentation that not only explains the interface but also the algorithm used and points the user to additional reference code and papers. The documentation can be found in the code, but it is also available as HTML-Version and on Read the Docs.
The relevant measures can be found in the file nolds/measures.py.
Contact information
If you have any questions, suggestions or corrections, you can find my current email address in my ORCID record.</dc:description>
<dc:identifier>https://zenodo.org/record/3814723</dc:identifier>
<dc:identifier>10.5281/zenodo.3814723</dc:identifier>
<dc:identifier>oai:zenodo.org:3814723</dc:identifier>
<dc:language>eng</dc:language>
<dc:relation>info:eu-repo/semantics/altIdentifier/url/https://github.com/CSchoel/nolds/releases/tag/0.5.2</dc:relation>
<dc:relation>doi:10.5281/zenodo.3814722</dc:relation>
<dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
<dc:subject>dynamical systems</dc:subject>
<dc:subject>entropy</dc:subject>
<dc:subject>chaos</dc:subject>
<dc:subject>fractal dimension</dc:subject>
<dc:subject>lyapunov exponent</dc:subject>
<dc:subject>hurst exponent</dc:subject>
<dc:subject>detrended fluctuation analysis</dc:subject>
<dc:subject>sample entropy</dc:subject>
<dc:subject>correlation dimension</dc:subject>
<dc:subject>python</dc:subject>
<dc:title>Nonlinear measures for dynamical systems</dc:title>
<dc:type>info:eu-repo/semantics/other</dc:type>
<dc:type>software</dc:type>
</oai_dc:dc>
500
14
views
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2021-12-07 05:44:52
|
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|
https://math.bme.hu/~szasz/lp.html
|
LIST OF PUBLICATIONS BY Domokos SZÁSZ
1.
On the general branching process with continuous time parameter. Studia Sci. Math. Hung. 2(1967), 227-246.
2.
3.
The applications of distribution functions in water resource management (in Hungarian). Hidrologiai közlöny, 1968, 433-446, (with M. Domokos)
4.
Generation of fitting distribution functions of discharges by electronic computer. Publ. 81. IASH "The use of analogue and digital computers in hydrology" (Tuscon, Arizona, 1968), Vol. II, 535-545. (with M. Domokos)
5.
Probability, Mathematical Statistics and their Applications. Lecture Notes. Ed.: Medgyessy and G. Tusnády, Math. Inst. of Hung. Acad. of Sciences, Budapest, 1968 (co-author)
6.
Asymptotically uniform sequences of measures. Studia Sci. Math. Hung. 4(1969), 313-329.
7.
The behaviour of power series in a boundary point of the circle of convergence
(in Hungarian), Mat.Lapok, 20(1969) 347-350.
8.
Matching problems. Colloquia Math. Soc. János Bolyai. 4. Combinatorial Theory and its Appl. (Balatonfüred, 1969), 695-703. (with G.O.H. Katona)
9.
Poissonian random measures and linear processes with independent pieces. Bull. de l'Acad. Polonaise des Sci. Ser. Math. 18(1970) No. 8. 475-482. (with W. Woyczynski)
10.
Once more on the Poisson process. Studia Sci. Math. Hung. 5(1970), 441-444.
11.
The asymptotic behaviour of sums of a random number of independent random variables (in Russian). Thesis. Moscow. 1971. pp. 98.
12.
Matching problems. J. of Combinatorial Theory. 10(1971), No. 1. 60-92. (with G.O.H. Katona)
13.
On a problem of summation theory with random indices (in Russian). Litovski Mat. Sbornik, 11(1971), 181-187. (with B. Freyer)
14.
Exercises and Problems in Probability Theory (in Hungarian) Budapest, 1971, pp. 331. (with K. Bognár, J. Mogyoródi, A. Prékopa and A. Rényi)
15.
On the convergence of sums of point processes with integer marks (in Russian)., Litovski Mat. Sbornik. 11(1971), 867-874.
16.
Limit theorems for stochastic processes stopped at random (in Russian). Theory of Probability and Appl. 16(1971), 557-569.
17.
On the weak convergence of sequences of probability distributions (in Hungarian). Matematikai Lapok, 11(1971), 283-287.
18.
On limiting classes of distributions for sums of a random number of independent, identically distributed random variables (in Russian). Theory of Probability and Appl. 17(1972), 424-439.
19.
On the rate of convergence in Levy's metric for randomly indiced sums. Colloquia Math. Soc. János Bolyai, 9(1972), 781-787.
20.
Limit theorems for the distribution of the sums of a random number of random variables. Ann. of Math. Statistics, 43(1972), 1902-1913.
21.
Stability and the law of large numbers from sums of a random number of random variables. Acta Scientiarum Math. 33(1972), 269- 274.
22.
On the convergence of sums of point processes with integer marks. Stochastic Point Processes, Ed. P.A.W. Lewis, Wiley, 1972, 607-615.
23.
Determination of fitting discharge distribution functions (in Hungarian). Hidrologiai Közlöny, 1972, No. 1. 1-15. (with M. Domokos).
24.
On rolling characteristic functions. Periodica Math. Hung. 3(1973), 13-17.
25.
Limit theorems for sums of a random number of random variables. Transactions of the Sixth Prague Conf. Prague, 1973, 833-838.
26.
A limit theorem for semi-Markov processes. J. of Applied Probability, 11(1974), 521-528.
27.
A collision model on the two-dimensional square-lattice. Z. für Wahrscheinlichkeitstheorie, 31(1974), 75-77. (with Dao-Quang-Tuyen)
28.
On a non-linear optimization problem (in Russian). Studia Sci. Math. Hung. 9(1974), 93-100.
29.
On a metrization of the vague convergence. Studia Sci. Math. Hung. 9(1974), 219-222.
30.
On a problem of Cox concerning controlled variability processes in Rk Ann. of Probability. 3(1975), 597-607. (with P. Gács)
31.
Some results and problems in the limit theory of random sums. (Independent case). Colloquia Math. Soc. János Bolyai. 11(1975),
32.
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April, 2013
File translated from TEX by TTH, version 3.61.
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2021-08-04 09:22:05
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http://openstudy.com/updates/4e4c69010b8b958804990bef
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## keebler01 Group Title show all work. Last fall, a gardener planted 95 iris bulbs. She found that only 80 of the bulbs bloomed in the spring. Find the empirical probability that an iris bulb of this type will bloom. Give answer as a fraction in lowest terms. How many of the bulbs should she plant next fall if she would like at least 91 to bloom? please show work! 2 years ago 2 years ago
1. satellite73 Group Title
$\frac{80}{95}=\frac{16}{19}$ in lowest terms
2. satellite73 Group Title
for the second part solve $\frac{16}{19}=\frac{91}{x}$ for x $x=\frac{19\times 91}{16}$ or about 108
3. satellite73 Group Title
since it says "at least" you might want to say 109
4. keebler01 Group Title
5. satellite73 Group Title
what step?
6. keebler01 Group Title
im not understanding what u wrote
7. satellite73 Group Title
can't you read it or don't you know where i got the numbers from?
8. satellite73 Group Title
if it looks funny refresh your browser because i wrote it in latex. you should be able to see the fractions clearly
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2014-07-30 17:38:32
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https://math.stackexchange.com/questions/3537284/internal-union-arrows-in-a-topos
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# Internal Union Arrows In A Topos
Below I describe an internal intersection arrow in a topos. My main question is, is there a corresponding idea of an internal union arrow, and if so what is the definition of it ?
Pointers to literature would also be helpful. I did see that
https://ncatlab.org/toddtrimble/published/An+elementary+approach+to+elementary+topos+theory
refers to an internal join arrow (which is probably what I want), but Todd Trimble does not seem to elaborate about it.
I learnt about internal intersection arrows from Exercise 13.9 of Elementary Categories, Elementary Toposes (by Colin Mclarty), but I am also unsure of their exact nature. I paraphrase this exercise below, in the hope that somebody can tell me exactly how internal intersection arrows are defined too (feel free to use the Mitchell–Bénabou language if it helps):
For an object $$A,$$ in a topos with subobject classifier $$\Omega,$$ we write $$x \in^A p$$ to denote that that pair $$\langle p,x \rangle$$ is a member of the subobject classified by the exponential evaluation arrow $$\Omega ^A \times A\overset{e}{\rightarrow} \Omega.$$ Mclarty asks us to define an internal intersection arrow
$$\Omega ^{\Omega ^A} \overset{\cap}{\rightarrow} \Omega ^A$$
and he tells us that $$\cap$$ is the exponential transpose of the arrow
$$\Omega ^{\Omega ^A} \times A \overset{}{\rightarrow} \Omega$$
which takes a pair $$\langle s, x \rangle$$ to true if and only if for every
$$p \in^{\Omega ^A} s$$
we have $$x \in^A p.$$
• If you're comfortable with the Mitchell-Benabou language, then I'm not sure what more there is to do; it's just defined in the internal language like it would be set-theoretically. So I'm guessing you'd actually prefer a pure arrows version? – Malice Vidrine Feb 6 at 23:01
• I think I've used the Mitchell-Benabou language to get at the internal intersection arrow, but I'm not sure, so I would appreciate seeing a pure arrow version. But the main thing I'm hoping for is some sort of description of the internal union arrow. – Richard Southwell Feb 6 at 23:34
• It is probably described in Goldblatt's Topoi. – Berci Feb 6 at 23:45
• Maybe, but I have looked at bit, and not seen it yet. – Richard Southwell Feb 6 at 23:52
For an object $$A$$, we can form the subobject $$\pi_{1,2}^*(\in^{\Omega^A})\wedge\pi_{2,3}^*(\in^{A})\hookrightarrow\Omega^{\Omega^A}\times\Omega^A\times A\qquad (1)$$ by taking the meet of the subobjects obtained by pulling back $$\in^{\Omega^A}$$ and $$\in^A$$ along the relevant product projections. Then $$\exists_{\pi_{1,3}}(\pi_{1,2}^*(\in^{\Omega^A})\wedge\pi_{2,3}^*(\in^{A}))\hookrightarrow\Omega^{\Omega^A}\times A\qquad (2)$$ is the image of the composition of the inclusion in (1) with the projection $$\pi_{1,3}:\Omega^{\Omega^A}\times\Omega^A\times A\to\Omega^{\Omega^A}\times A$$. Intuitively, (2) is the extension of the predicate $$\exists P(a\in P\wedge P\in X)$$; i.e. all the $$\langle a,X\rangle$$ in the image of the map that deletes the middle term from $$\langle a,P,X\rangle$$ with $$a\in P\in X$$.
The subobject in (2) has a classifying map; call it $$U:\Omega^{\Omega^A}\times A\to \Omega$$. Then, as with the intersection map, the union map $$\bigvee:\Omega^{\Omega^A}\to\Omega^A$$ is obtained by taking the exponential transpose of $$U$$.
The only difference between this map and the intersection map is whether you're using the left or right adjoint to $$\pi_{1,3}^*:\mathrm{Sub}(\Omega^{\Omega^A}\times A)\to\mathrm{Sub}(\Omega^{\Omega^A}\times\Omega^A\times A)$$ in going from (1) to (2); they each give a different subobject of $$\Omega^{\Omega^A}\times A$$, and so a different classifying arrow to take the transpose of in the last step.
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2020-10-31 04:14:25
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https://www.ademcetinkaya.com/2023/02/lfmdp-lifemd-inc-8875-series-cumulative.html
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Outlook: LifeMD Inc. 8.875% Series A Cumulative Perpetual Preferred Stock is assigned short-term Ba1 & long-term Ba1 estimated rating.
Time series to forecast n: 18 Feb 2023 for (n+16 weeks)
Methodology : Inductive Learning (ML)
## Abstract
LifeMD Inc. 8.875% Series A Cumulative Perpetual Preferred Stock prediction model is evaluated with Inductive Learning (ML) and Ridge Regression1,2,3,4 and it is concluded that the LFMDP stock is predictable in the short/long term. According to price forecasts for (n+16 weeks) period, the dominant strategy among neural network is: Buy
## Key Points
1. How do predictive algorithms actually work?
2. Stock Rating
3. Understanding Buy, Sell, and Hold Ratings
## LFMDP Target Price Prediction Modeling Methodology
We consider LifeMD Inc. 8.875% Series A Cumulative Perpetual Preferred Stock Decision Process with Inductive Learning (ML) where A is the set of discrete actions of LFMDP stock holders, F is the set of discrete states, P : S × F × S → R is the transition probability distribution, R : S × F → R is the reaction function, and γ ∈ [0, 1] is a move factor for expectation.1,2,3,4
F(Ridge Regression)5,6,7= $\begin{array}{cccc}{p}_{a1}& {p}_{a2}& \dots & {p}_{1n}\\ & ⋮\\ {p}_{j1}& {p}_{j2}& \dots & {p}_{jn}\\ & ⋮\\ {p}_{k1}& {p}_{k2}& \dots & {p}_{kn}\\ & ⋮\\ {p}_{n1}& {p}_{n2}& \dots & {p}_{nn}\end{array}$ X R(Inductive Learning (ML)) X S(n):→ (n+16 weeks) $\stackrel{\to }{R}=\left({r}_{1},{r}_{2},{r}_{3}\right)$
n:Time series to forecast
p:Price signals of LFMDP stock
j:Nash equilibria (Neural Network)
k:Dominated move
a:Best response for target price
For further technical information as per how our model work we invite you to visit the article below:
How do AC Investment Research machine learning (predictive) algorithms actually work?
## LFMDP Stock Forecast (Buy or Sell) for (n+16 weeks)
Sample Set: Neural Network
Stock/Index: LFMDP LifeMD Inc. 8.875% Series A Cumulative Perpetual Preferred Stock
Time series to forecast n: 18 Feb 2023 for (n+16 weeks)
According to price forecasts for (n+16 weeks) period, the dominant strategy among neural network is: Buy
X axis: *Likelihood% (The higher the percentage value, the more likely the event will occur.)
Y axis: *Potential Impact% (The higher the percentage value, the more likely the price will deviate.)
Z axis (Grey to Black): *Technical Analysis%
## IFRS Reconciliation Adjustments for LifeMD Inc. 8.875% Series A Cumulative Perpetual Preferred Stock
1. An alternative benchmark rate designated as a non-contractually specified risk component that is not separately identifiable (see paragraphs 6.3.7(a) and B6.3.8) at the date it is designated shall be deemed to have met that requirement at that date, if, and only if, the entity reasonably expects the alternative benchmark rate will be separately identifiable within 24 months. The 24-month period applies to each alternative benchmark rate separately and starts from the date the entity designates the alternative benchmark rate as a non-contractually specified risk component for the first time (ie the 24- month period applies on a rate-by-rate basis).
2. In applying the effective interest method, an entity identifies fees that are an integral part of the effective interest rate of a financial instrument. The description of fees for financial services may not be indicative of the nature and substance of the services provided. Fees that are an integral part of the effective interest rate of a financial instrument are treated as an adjustment to the effective interest rate, unless the financial instrument is measured at fair value, with the change in fair value being recognised in profit or loss. In those cases, the fees are recognised as revenue or expense when the instrument is initially recognised.
3. Adjusting the hedge ratio by decreasing the volume of the hedged item does not affect how the changes in the fair value of the hedging instrument are measured. The measurement of the changes in the value of the hedged item related to the volume that continues to be designated also remains unaffected. However, from the date of rebalancing, the volume by which the hedged item was decreased is no longer part of the hedging relationship. For example, if an entity originally hedged a volume of 100 tonnes of a commodity at a forward price of CU80 and reduces that volume by 10 tonnes on rebalancing, the hedged item after rebalancing would be 90 tonnes hedged at CU80. The 10 tonnes of the hedged item that are no longer part of the hedging relationship would be accounted for in accordance with the requirements for the discontinuation of hedge accounting (see paragraphs 6.5.6–6.5.7 and B6.5.22–B6.5.28).
4. An example of a fair value hedge is a hedge of exposure to changes in the fair value of a fixed-rate debt instrument arising from changes in interest rates. Such a hedge could be entered into by the issuer or by the holder.
*International Financial Reporting Standards (IFRS) adjustment process involves reviewing the company's financial statements and identifying any differences between the company's current accounting practices and the requirements of the IFRS. If there are any such differences, neural network makes adjustments to financial statements to bring them into compliance with the IFRS.
## Conclusions
LifeMD Inc. 8.875% Series A Cumulative Perpetual Preferred Stock is assigned short-term Ba1 & long-term Ba1 estimated rating. LifeMD Inc. 8.875% Series A Cumulative Perpetual Preferred Stock prediction model is evaluated with Inductive Learning (ML) and Ridge Regression1,2,3,4 and it is concluded that the LFMDP stock is predictable in the short/long term. According to price forecasts for (n+16 weeks) period, the dominant strategy among neural network is: Buy
### LFMDP LifeMD Inc. 8.875% Series A Cumulative Perpetual Preferred Stock Financial Analysis*
Rating Short-Term Long-Term Senior
Outlook*Ba1Ba1
Income StatementB2Ba2
Balance SheetBaa2Baa2
Leverage RatiosCBaa2
Cash FlowCBaa2
Rates of Return and ProfitabilityB1Caa2
*Financial analysis is the process of evaluating a company's financial performance and position by neural network. It involves reviewing the company's financial statements, including the balance sheet, income statement, and cash flow statement, as well as other financial reports and documents.
How does neural network examine financial reports and understand financial state of the company?
### Prediction Confidence Score
Trust metric by Neural Network: 91 out of 100 with 843 signals.
## References
1. Knox SW. 2018. Machine Learning: A Concise Introduction. Hoboken, NJ: Wiley
2. V. Borkar. Q-learning for risk-sensitive control. Mathematics of Operations Research, 27:294–311, 2002.
3. Harris ZS. 1954. Distributional structure. Word 10:146–62
4. R. Sutton and A. Barto. Reinforcement Learning. The MIT Press, 1998
5. Abadie A, Diamond A, Hainmueller J. 2015. Comparative politics and the synthetic control method. Am. J. Political Sci. 59:495–510
6. V. Borkar and R. Jain. Risk-constrained Markov decision processes. IEEE Transaction on Automatic Control, 2014
7. A. Tamar and S. Mannor. Variance adjusted actor critic algorithms. arXiv preprint arXiv:1310.3697, 2013.
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2023-03-27 07:50:49
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https://chemistry.stackexchange.com/questions/133032/ozone-in-ozone-layer/133034
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# Ozone in ozone layer [closed]
If ozone is a gas, and gases have the highest entropy, then how does the ozone gas stay within a few layers of the atmosphere, even though they span for kilometers?
• Entropy and ozone at the top of the atmosphere are two unconnected things. Harmful UV rays from the Sun are unable to penetrate deep into the atmosphere because they encounter oxygen molecules. They absorb the UV and form ozone on the top. If ozone reached us, nobody could survive. It is a harmful thing. Read more about the en.wikipedia.org/wiki/Ozone%E2%80%93oxygen_cycle – M. Farooq May 3 at 14:39
• – Faded Giant May 3 at 15:33
• @M.Farooq - For clarification - there's plenty of ground level ozone around. It's not good for us, but it's not so bad at low concentrations that we don't survive. I suspect most people are familiar with the smell of ozone, even if they don't know what they're smelling. – Andrew May 3 at 15:47
• Right, Andrew, ozone at part per million levels it is not that great! It immediately hurts the throat if you are sensitive. If you recall the smell of older photocopy machines, the smell is not that pleasant but fresh rain is of wonderful but that must be parts per billion conc. – M. Farooq May 3 at 15:58
• Plus some rare highly reactive agens like peroxyacetylnitrate can be created, what reportedly acted in past during some Los Angeles smog situations as plant defoliant. Additionally, ozone is the starter of immission damage to conifer trees by SO2. – Poutnik May 3 at 16:07
It does not have much to do with entropy, rather with the way and place of ozone creation.
Stratospheric ozone is produced typically at altitude 20-30 km by UVC radiation with $$\lambda \lt \pu{280 nm}$$:
$$\ce{O2 + \nu -> 2 O}$$ $$\ce{O + O2 -> O3}$$
See ozone cycle as courtesy of @M. Farooq.
Ozone in lower troposphere troposphere is created by UVB (280-320 nm) (+UVA >320 nm ??) mostly due catalytic effects of nitrogen oxides that come typically of the oxidative smog of the Los Angeles type:
$$\ce{NO2 + \nu -> NO2^{*}}$$ $$\ce{NO2^{*} + O2 -> NO + O3}$$ $$\ce{2 NO + O2 -> 2 NO2}$$
Technically, the concentration and positioning of ozone in the atmosphere likely relates directly to both ozone formation, stabilization and a destruction cycle.
While formation creation cycles has already been outlined, I would like to add more detail on the chemistry based on this source:
Creation:
$$\ce{O2 + ℎν → 2 O• }$$
$$\ce{O• + O2 → O3 }$$
which is followed by the 'ozone–oxygen cycle' where the ozone molecules formed by the reaction above absorbs radiation in wavelengths between UV-C and UV-B.
$$\ce{O3 + ℎν(240–310 nm) → O2 + O }$$
forming atomic oxygen which can further react with dioxygen:
$$\ce{O + O2 → O3 + kinetic energy }$$
The cited net effect of the ozone–oxygen cycle is the conversion of penetrating UV-B light into heat, with no net loss of O3. This cycle reputedly keeps the ozone layer stable and results in the protection of the lower atmosphere from harmful UV radiation.
Removal of Ozone:
$$\ce{O3 + O· → 2 O2}$$
$$\ce{2 O· → O2 }$$
Also, per a source, on the net effect of the two reactions, to quote:
$$\ce{2 O3 → 3 O2 }$$
This reaction proceeds more rapidly with increasing temperature.
So, higher colder altitudes are more conducive to the preservation of created ozone.
On its destruction cycles, to quote a source:
Ozone is a highly reactive molecule that easily reduces to the more stable oxygen form with the assistance of a catalyst. Cl and Br atoms destroy ozone molecules through a variety of catalytic cycles. In the simplest example of such a cycle,[11] a chlorine atom reacts with an ozone molecule (O3), taking an oxygen atom to form chlorine monoxide (ClO) and leaving an oxygen molecule (O2). The ClO can react with a second molecule of ozone, releasing the chlorine atom and yielding two molecules of oxygen. The chemical shorthand for these gas-phase reactions is:
$$\ce{Cl· + O3 → ClO + O2}$$
A chlorine atom removes an oxygen atom from an ozone molecule to make a ClO molecule
$$\ce{ClO + O3 → Cl· + 2 O2}$$
This ClO can also remove an oxygen atom from another ozone molecule; the chlorine is free to repeat this two-step cycle.
Now, pollutants in the atmosphere include chloro-(and bromo-) organics, which can, under UV photolysis, liberate a chlorine (or bromine) radical.
So, as one gets closer to the surface of the earth, radiation-induced ozone formation is abated, warmer temperatures are unfavorable and any diffused ozone entering the lower layers, could be further subject to attack by increasing concentration of photosensitized pollutants engaging in catalytic destruction cycles.
And, that is why the ozone layer resides at a high altitude, maintains itself and is not found closer to the surface of the earth.
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2020-08-13 09:44:25
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http://quant.stackexchange.com/tags/yield/new
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Tag Info
3
You can calculate Future Value with Matlab as follow FutureVal = fvdisc(Settle, Maturity, Price, Discount, Basis) Settle: Settlement date. Maturity: Exercise date. Price: present value of the security. Discount: Bank discount rate of the security. Basis: Day-count basis of the instrument(actual/360) For example, Settle = '03/15/2015'; Maturity = ...
1
The time $0$ forward rate from tme $n-1$ to time $n$ is $$1 + i_0(n-1, n) = \dfrac{(1 + s_0(n))^n}{(1+s_0(n-1))^{n-1}}$$ where $s_0(n)$ is the $n$-year spot rate and $i_0(n-1, n)$ is the time $0$ forward rate from time $n-1$ to time $n$. The term structure of interest rates must be increasing to avoid arbitrage opportunities. ...
1
In a case like this, where the settlement date is in the middle of the coupon period, it is not right to use PV = -110 (minus the purchase price) in Step 3. Instead you should increase the purchase price by the accrued interest, which is a fraction of the coupon based on how far the settlement date is within the current coupon period. (So for ex if you are ...
Top 50 recent answers are included
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2015-07-05 04:34:00
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https://stats.stackexchange.com/questions/259595/distribution-of-inter-arrival-times-in-a-poisson-process
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# Distribution of inter arrival times in a Poisson process
I am new to Statistics. I am studying Poisson process, I have certain questions to ask.
A process of arrival times in continuous time is called a Poisson process of rate $\lambda$ if the following two conditions hold:
• The number of arrivals in an interval of length $t$ is $\text{Pois}(\lambda t)$ random variable.
• The number of arrivals that occur in disjoint time intervals are independent of each other.
Let $X_1$ denote the time of first arrival in a Poisson process of rate $\lambda$. Let $X_2$ denote the time elapsed between the first arrival and the second arrival. We can find the distribution of $X_1$ as follows: $$\mathbb{P}(X_1>t)=\mathbb{P}\left(\text{No arrivals in }[0,t]\right)=\mathrm{e}^{-\lambda t}$$ Thus $\mathbb{P}(X_1\le t)=1-\mathrm{e}^{-\lambda t}$, and hence $X_1\sim\text{Expo}(\lambda)$.
Suppose we want to find the conditional distribution of $X_2$ given $X_1$. I found the following discussion in my textbook.
$$$\begin{split}\mathbb{P}(X_2>t|X_1=s)&=\mathbb{P}\left(\text{No arrivals in }(s,s+t]\middle | \text{Exactly one arrival in [0,s]}\right)\\&=\mathbb{P}\left(\text{No arrivals in }(s,s+t]\right)\\&=\mathrm{e}^{-\lambda t}\end{split}$$$.
Thus, $X_1$ and $X_2$ are independent, and $X_2\sim\text{Pois}(\lambda)$.
However, I have the following questions regarding the above discussion.
1. Since $X_1$ is a continuous random variable, $\mathbb{P}(X_1=k)=0$ for every $k\in\mathbb{R}$. Thus, $\mathbb{P}(X_1=s)=0$. In other words, we are conditioning on an event with zero probability. But when I studied conditional probability, conditioning on events with zero probability was not defined. So in this case, is conditioning on an event with zero probability valid?
2. Second, assuming that conditioning on $X_1=s$ is valid, what we have found is the conditional distribution of $X_2$ given $X_1=s$. In other words, the conditional distribution of $X_2$ given $X_1$ is $\text{Expo}(\lambda)$, not the distribution of $X_2$ itself. But the author claims that $X_2\sim\text{Expo}(\lambda)$. Why is this true?
The discussion in your book is not phrased correctly in some aspects, but first let me address your question about conditioning on an event of probability $0$; something that is explicitly forbidden in the definition of conditional probability in the earlier chapter of your book.
For jointly continuous random variables $X$ and $Y$ with joint pdf $f_{X,Y}(u,v)$, the conditional pdf of $Y$ given that $X = x$ is defined to be $$f_{Y\mid X}(v\mid X = u) = \begin{cases} \displaystyle \frac{f_{X,Y}(u,v)}{f_{X}(u)}, & \text{if }~f_{X}(u)>0,\\0, &\text{otherwise.}\end{cases}$$ where $f_X(u)$ is the (marginal) pdf of $X$. The conditional complementary CDF is $$1-F_{Y\mid X}(t\mid X = u) = P\{Y > t\mid X = u\} = \int_t^\infty f_{Y\mid X}(v\mid X = u) \,\mathrm dv$$ Now, in your application, $P\{X_2 > t\mid X_1 = s\}$ can be calculated directly since we are told that the first arrival occurred at $s$ and are being asked for the conditional probability that no arrivals have occurred in $(s,s+t]$. But, what happens in $(s,s+t]$ is independent of what happened in $(0,s]$ since the time intervals are disjoint. That is, $P\{\text{no arrivals in} ~ (s,s+t]\mid X_1=s\}$ is the same regardless of whether we assume that there was an arrival at $s$ or the first arrival occurred before time $s$, and so $$P\{X_2 > t\mid X_1 = s\} = P\{\text{no arrivals in} ~ (s,s+t]\} = e^{-\lambda t}.$$ and thus we get that the conditional pdf $f_{X_2\mid X_1 = s}(v\mid X_1 = s)$ is the same as the unconditional pdf $f_{X_2}(v) = \lambda e^{-\lambda v}, v > 0$. Conditionally or unconditionally, the distribution of $X_2$ is exponential with parameter $\lambda$. Furthermore, \begin{align} f_{X_2}(v) = f_{X_2\mid X_1 = s}(v\mid X_1 = s) = \displaystyle \frac{f_{X_1,X_2}(s,v)}{f_{X_1}(s)} \implies f_{X_1,X_2}(s,v) = f_{X_1}(s)f_{X_2}(v) \end{align} showing that $X_1$ and $X_2$ are independent (exponential random variables with parameter $\lambda$).
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2020-01-26 09:42:40
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https://homework.zookal.com/questions-and-answers/hi-i-am-working-on-a-physics-problem-but-got-646508973
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1. Math
2. Algebra
3. hi i am working on a physics problem but got...
# Question: hi i am working on a physics problem but got...
###### Question details
Hi, I am working on a physics problem but got stuck on the algebra part of the solution, can someone please help me with simultaneous equations?
I am applying Snell's Law to find the refractive index of a prism (${n}_{2}$), however, the only information I have is:
${\theta }_{1}=37°$
${\theta }_{4}=90°$
${n}_{1}=1$
And the two equations would be:
This was an optics lab session and I am using a method called total internal reflection and then finding the refraction index from the critical angle (which is ${\theta }_{3}$ in this problem). After that point I used trig identities to resolve $\mathrm{sin}\left(60-{\theta }_{3}\right)$ but then I got stuck and not sure if I equated the equations properly.
Thank you very much,
Michele
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2021-04-14 22:31:32
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http://interactivepython.org/runestone/static/StudentCSP/CSPWhileAndForLoops/ch8_exercises.html
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# Chapter 8 Exercises¶
1. Fix the 5 syntax errors in the code below to print a countdown of the numbers from 10 to 0.
2. The following code will loop infinitely. Make one change that will make it loop only 5 times.
3. Make 5 changes to the code below to correctly print a count up from -10 to 0.
4. Fix the errors in the code below so that it uses 2 loops to print 8 lines of *.
5. Finish lines 1 and 5 so that the following code correct prints all the values from -5 to -1.
6. Complete the code on lines 4 and 6 so that it prints the number 6.
7. The code below is supposed to print an estimate of the square root. But, the indention is wrong on 4 lines. Fix it.
8. The function currently takes a start and stop argument and uses a for loop to find the sum of all the numbers between them (inclusive). Change the for loop to a while loop while still using the parameters.
9. The program below is supposed to print the times tables for 1 to 3, but there are 5 errors. Fix the errors.
10. Rewrite the code that prints the times tables for 1 to 3 using a while loop and a for loop instead of two for loops.
11. Rewrite the following code to use a while loop instead of a for loop.
12. Fix the errors so that the code gets the average of the numbers from 1 to 10.
13. Rewrite the following code to use a while loop instead of a for loop.
14. The code below currently enters a loop where it keeps printing “Even”. Fix the code so that it prints “Even” and “Odd” for numbers 0 to 9.
15. Modify the code below to create a function that will take numbers as input until you enter a negative number and then will return the average of the numbers.
16. Fix and change the code so it prints a table of division instead of multiplication for -10 to -1.
18. Write a procedure that takes a user input and keeps asking for a user input until the input is “Hello”. If the input is not “Hello”, it should print “This is your n wrong try.” where n is the number of times they have put an input in. If they type “Hello”, the procedure should print “Success!”. Hint: != means does not equal
20. Write a procedure that takes an int argument and uses a while loop to create a right-triangle like shape out of *. The first row should have 1 star and the last should have n stars where n is the argument passed.
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2017-12-11 01:51:20
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https://math.stackexchange.com/questions/1574472/a-system-of-linear-equations-has-a-solution-iff-b-in-span-textcol-a/1574798
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# A system of linear equations has a solution iff $b \in Span(\text{col} (A))$?
Prove that a system of linear equations $Ax=b$, where $A_{m\times n}$ has a solution iff $b \in Span(\text{col} (A))$.
If $b \in Span(\text{col} (A))$ then $b$ can be expressed uniquely with the vectors that form the columns of $A$, i.e., $b$ is a a linear combination of the columns of $A$ hence it is necessarily a solution?
If $Ax=b$ has a solution then necessarily $b$ belongs to the span of $\text{col} (A)$?
What is the geometric/intuitive meaning of these statements and how to show their correctness?
Thank you!
• That is quite simply because the column vectors of $A$ are the images of the basis of $\mathrm R^n$ by the linear map associated with the matrix, and any vector of $\mathrm R^n$ is in the span of the basis (by definition), hence its image is in the span of the images of the basis. – Bernard Dec 14 '15 at 1:11
Define vectors $\def\*#1{\boldsymbol{#1}} \*{v_1}, \*{v_2}, \ldots, \*{v_n}.$ to be the columns of $A$. That is, $A = \left[ \*{v_1}, \*{v_2}, \ldots, \*{v_n} \right]$
Let $\*x$ be a vector $\left[\begin{array}{c} x_1 \\x_2\\ \ldots \\x_n \end{array} \right]$. Then $A \*x = x_1 \*{v_1} + x_2 \*{v_2} + \ldots + x_n \*{v_n}$.
What is the span of $\*{v_1}, \*{v_2}, \ldots, \*{v_n}$?
$$\mathrm{Span}\left( \*{v_1}, \*{v_2}, \ldots, \*{v_n} \right) = \left\{ \left. \lambda_1 \*{v_1} + \lambda_2 \*{v_2} + \ldots + \lambda_n\*{v_n} \; \right| \; \lambda_1,\lambda_2, \ldots, \lambda_n \in \mathbb{R} \right\}$$
From this, it should be straightforward to show that $A\*x = \*b$ has a solution iff $\*b$ belongs to span of the columns of $A$.
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2019-05-24 15:30:52
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http://math.stackexchange.com/questions/133307/help-with-constant-of-integration
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# Help with Constant of Integration
Ok, I hope this question makes sense...
Suppose the the variable y has a distribution of F(y|x).
Suppose after some work I have the following equation:
(1) $\int D dD = \int_{-\infty}^\infty[\int h(x,y,g)dg]d(F(y|x))$
Clearly, we have that $\int D dD = 0.5*D^2 +C_1$. Suppose that $\int h(x,y,g)dg = g(x,y)+C_2$
where $C_1$ & $C_2$ are both constants of integration.
My question is does $C_2$ necessarily depend on x and y? Put another way, can I rewrite equation (1) as:
$0.5*D^2 +C = \int_{-\infty}^\infty g(x,y)d(F(y|x))$
or must I leave it as:
$0.5*D^2 +C_1 = \int_{-\infty}^\infty [g(x,y)+C_2]d(F(y|x))$
?
Hope, I managed to make some sense here.
I do have an initial condition that I would satisfy to find the constants, its that D(x)=0 when x=0. But, I'm still confused as to what that would mean. Would that imply that we have:
$C=\int_{-\infty}^\infty g(0,y)dF(y|x=0)$
I wouldn't worry so much about the infinite limits, its just there as a substitute for the range of y, if you prefer, you can think about the problem as being from $a$ to $b$ instead of the infinite limits.
-
It seems to me that your question "does $C_2$ necessarily depend on $x$ and $y$" may indicate a misunderstanding of the concept of a constant of integration. A constant of integration can't depend on anything, since it can take an arbitrary value. An indefinite integral, as the term suggests, is not a definite quantity, with the constant of integration somehow to be determined; it represents an entire class of functions that differ only by an additive constant. It's only when you add additional conditions such as initial values that it would make sense to ask whether the constant of integration as fixed by these conditions depends on some parameters.
@anon: Yes, this is precisely the sort of setting I was referring to where there are further constraints on the constants of integration. I'm not sure that "the constants of integration are functions of other independent variables" is a good way to express this, but that's just a linguistic issue -- the main point is that I don't see anything in the question that indicates this sort of setting, and without such a setting the question whether $C_2$ depends on $x$ and $y$ makes no sense. – joriki Apr 18 '12 at 6:19
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2015-11-27 12:02:20
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https://codegolf.stackexchange.com/questions
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# All Questions
10,506 questions
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2019-04-22 07:02:36
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https://civil.gateoverflow.in/876/gate2017-ce-1-13
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The reaction rate involving reactants $A$ and $B$ is given by $-k[A]^{\alpha} [B]^{\beta}$. Which one of the following statements is valid for the reaction to be first-order reaction?
1. $\alpha=0$ and $\beta=0$
2. $\alpha=1$ and $\beta=0$
3. $\alpha=1$ and $\beta=1$
4. $\alpha=1$ and $\beta=2$
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2022-10-06 07:28:59
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{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6735053658485413, "perplexity": 149.82094000539198}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030337731.82/warc/CC-MAIN-20221006061224-20221006091224-00759.warc.gz"}
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https://notes.dedenf.com/page/59/
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# JakartaJS Meetup
Today, after hour, finally got a chance to attend one of the hottest Meetup, JakartaJS, even though i came late to the Meetup, but it was fun. Met few friends there, catching up old story with my friend, updating what was what. The presentation also quite fun, i just got there and people from Yes Boss is already giving their deck, i missed the first one.
last year i bought few domain, i just bought it, and never had a chance to think what am i gonna do with it, to name a few, i bought pakeapa.com, when i decided to bought it, i think of it’s like a blog that contain information about software, open source or anything else that other people do, have, had.
and it turns out it did, even the content has been evolving into like an interview (it did!), it borrows the idea from usesthis. and i’m glad Daniel (the onwer of the blog) is pleased and listed pakeapa.com on his site, and he’s such a nice guy, gave some advice of how i could improve.
second, i bought Jakartadev.org, it’s basically a newsletter service, focusing on developers, opensource, technology. it’s a weekly newsletter, i will send it every monday, it contain a lot of information, tutorial, and tools that you could use to speed up developement, curated by yours trully, and i hope it will become a habit for me to read tutorials, howto, or anything that could improve my dev skills.
i hope you enjoy it as much as i do.
Tag: #developer
# Setapak Sriwedari
You have no idea.
Tag: #rant
# Announcing Version 2.0
In an effort to make Pixyll easier to customize and more aesthetically pleasing, we’ve released version 2.0.
Pixyll now features:
• Line anchors in code blocks and new syntax highlighting
• A customizable variables file
• Modular, and lighter weight CSS
• No more max-width media queries
Tag:
Tag: #rant
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2023-03-25 01:06:07
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https://www.researchgate.net/publication/290369150_Dictatorship_Democracy_and_Development
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Chapter
# Dictatorship, Democracy, and Development
Authors:
To read the full-text of this research, you can request a copy directly from the author.
## Abstract
This book shows that in calling economics the ‘dismal science’, Thomas Carlyle was profoundly wrong. The influence of economic thinking on other social sciences is bringing about a theoretical integration of all the social sciences under one overarching paradigm. The ten chapters of this book illustrate the intellectual advances that account for this unified view of economics and societies. The key theme that emerges is the interaction between political, economic, legal, and social forces. Examples of this include the political influence of corruption and special interest groups, the organizational structure of a government, the effect of commercial law, and the differences between communities with high and low social fragmentation. All these affect and are affected by economic conditions.
## No full-text available
... However, some theories question the role of political stability in promoting economic growth, especially when it comes to keeping up with an accelerated pace of economic growth (Olson, 1993). In the long term, a stable society with unchanged borders and an entrenched political regime is increasingly resistant to change. ...
Article
Full-text available
The economy, like all other human activities, would not be properly exercised in a place where there is a societal unsteadiness. Indeed, governments place the maintenance of political stability at the center of their interests. So, what is the impact of maintaining this stability upon the economic performance? To provide an answer to this question, we have studied this dynamic on the most unstable continent on the planet, Africa. This paper attempts 36 TITRE DE L'ARTICLE International Journal of Economics and Management Research, V.1, N°4, Juin-Juillet 2021 to model the relationship between these two components under a macro-dynamic model, Autoregressive Delayed Model (ARDL), on a panel of forty African countries over a period of 20 years that goes from 1997 to 2017. The paper's empirical results reveal that political stability has an impact on GDP per capita through investment. Moreover, the nature of this impact may depend on the location of an African country in the sample. Indeed, this model allows us to distinguish three categories of countries where the impact of stability on economic performance is either positive, negative or neutral. In the short run, political stability has a positive impact on GDP per capita across the Southern African region, while its impact is neutral for North African countries.
... This work ranges from applications of rational choice theory to heterodox political economy, but a common theme is the evolution of state-society relations through bargaining over taxation. The emergence of institutions to protect property rights, establish checks and balances on the executive, or provide political stability has been traced to different aspects of the tax bargain (North, 1990: 49;Olson, 2000). ...
Article
Full-text available
The digitization of taxation systems can assist inclusion. However, it can also inadvertently lead to adverse outcomes for the poor in developing countries where many firms in the informal sector have low capabilities. Moreover, larger formal sector firms are often politically networked and in a position to engage in extractive informal transactions that digitization alone cannot restrict. Thus, while digitization creates tools for the enforcement of formal regulations, formalization can be unequal. This contribution focuses on digitized taxation as an application of a more general problem with digitization as a tool for formalization, referring to evidence from the rollout of the Goods and Services Tax (GST) in India. Using the analysis of political settlements, the authors distinguish between types of rule violations in developing economies. Networked higher-capability firms engage in ‘informal’ transactions when they violate rules to extract rents. This is different from the informality of unregistered micro and small enterprises in the informal sector who often violate rules they cannot adhere to, and make informal payments to enforcers to continue operating. When digital technologies are used in these contexts, adverse outcomes for welfare and inclusion can follow from ‘premature formalization’. A more cautious and inclusive path to formalization is necessary to protect vulnerable groups.
... 5 While average incomes have increased, the rise in inequality is most pronounced "in the upper parts of the distribution in most countries" (Jaumotte et al., 2013). Further, many countries, mainly autocracies, do not have strong developed markets or democratic institutions (Olson, 1993). Hence, economic agents in autocratic countries may behave quite differently than those in developed economies (Adam et al., 2011). ...
Article
We identify new country characteristics that influence cross border equity flows: income inequality, autocracy, and sovereign wealth funds. Using 149 source countries and 34 OECD host countries for 2002‐2013, we find that OECD host countries receive higher Foreign Portfolio Investment (FPI) inflows from source countries with high income inequality and source countries with a sovereign wealth fund; but lower inflows from autocratic source countries. We argue that concentrated wealth in a society, overseas investments for the benefit of future generations, and political regimes influence FPI. Those variables have been understudied though they provide valuable indicators for policymakers and investors. We supplement our core analysis with realistic interactions between those new variables, and with the increasing importance of tax havens. Our results hold throughout a variety of robustness checks. This article is protected by copyright. All rights reserved.
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This essay discusses how criminal organizations in South America have reconfigured themselves in the face of the pandemic scenario experienced since late 2019. In particular, it examines how the practices and actions carried out by these associations were carried forward in the pandemic, maintaining or even giving force the influence of crime on the life of South American society. It is argued that in order to understand criminal governance, it is essential to consider the discussion of how the territories in which these organizations operate are not in conflict with the state, but rather there is a hybrid governance in which criminal organizations and the state coexist as two sources of legitimacy and authority. There is a complementarity of actions, in which criminal organizations were seen during the pandemic occupying state functions in the adoption of protective measures, and provision of assistance, but always with a clear objective of maintaining the status quo of their illicit activities. In the end, it is clear that criminal organizations have consolidated themselves as a governance space recognized as legitimate during the pandemic, complementing and, perhaps even, eclipsing the role of state bureaucracy in the face of the seriousness of the health emergency experienced, especially in the cases of Brazil and Colombia.
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The traditional perception is that foreign aid provides leaders in recipient states access to nontax revenue, which incumbents may be able to manipulate in order to provide public or private goods as is required to maintain office. Recognizing this possibility, donors have been shifting away from direct government-to-government aid and toward bypass aid, administered by NGOs and civil society groups rather than the regime directly. Receiving aid through alternative channels is designed to increase aid’s effectiveness, yet it has potential implications for incumbent leaders who may have less ability to manipulate aid receipts to their benefit. In this paper, we argue that bypass aid should negatively affect leaders’ tenure, conditional on the political institutions in place. Using data on bypass aid from 2004 to 2017, we find evidence of a punishing effect and conclude that bypass aid is a particularly acute problem for leaders in authoritarian regimes. The findings imply that efficiency and stability may present a tradeoff for potential donors and that bypass aid may not be the panacea of the aid effectiveness movement.
Chapter
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There is evidence for mixed effects of democracy on the development of the financial sector. Part of the literature explains theses controversies by assuming that democracy’s effect on development is non-linear. This paper tries to bring new insights into this debate by examining non-linearities by the way of a new method of analysis, i.e., a panel smooth transition regression model. We use a sample of 90 developing countries over the period 1984–2007 and rely on panel smooth threshold regression, fixed effects, and system GMM models. Findings confirm the fact that the relationship between democracy and financial development is indeed non-linear. Furthermore, results demonstrate that the level of democracy and financial system development are correlated in a U-shaped manner. Hence, there are two extreme regimes where democracy’s impact on the financial system is different depending on the democracy level. Particularly, there is a threshold level of democracy, estimated at 5, beyond which more democracy enhances the financial sector development and below which democracy hinders the development of the financial system.
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This paper reviews the Roman tax collection system since the Late Republic to the Principality, focusing on the transition from the tax-farming system to a more centralized, census-based administration. We attempt to justify this transition according to New Institutional Economic theories (Transaction Cost Economics and Property Rights Theory). The paper argues that, during the Republic, the auction-based system of tax farming ended up giving place to opportunistic behaviors and abusing practices due to information asymmetries and contract incompleteness, enhanced by the collusion of tax farmers and governors. The Principality improved the efficiency of the tax collection system through the introduction of a bureaucratic and census-based administration, which allowed imperial employees to monitor the tax-farming activities.
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This chapter characterises the relations between religion, institutions, and the transparency–prosperity nexus. It explains how economic prosperity, democracy, and transparency are part of a feedback loop that constitutes a single phenomenon. More importantly, this chapter deepens the institutional analysis by concentrating on the particular historical influence of religion on the different legal traditions in Europe and the Americas. It is the cornerstone of Part 3 and, as such, of the entire book. The Reformation brought forth a wide range of modern institutions. Among these, education and democracy are the most crucial ones for ensuring prosperity/transparency outcomes. Likewise, Protestantism has impacted the secularisation of the state in Protestant countries (and also in Roman Catholics, albeit to a lesser, more indirect extent). Protestantism fosters horizontal power relations and secular-rational attitudes towards authority. Thus, such egalitarian and secular attitudes are linked to greater transparency and prosperity. The Lutheran German Revolution formed the basis of the various later Protestant, dissenting revolutions and legal traditions (i.e. British and American). Some of its concepts (e.g. separation of state functions from the church; state-sponsored education) permeate all modern legal systems to this day and ended the monopoly of Roman canon law. Regardless of the advances made by Roman Catholicism in the Second Vatican Council (Vatican II: 1962–1965), corporatist ideologies remain prevalent, mostly in Latin America. But while Roman Catholic discourse has shifted, the institutional inertia persists and maintains the hierarchical status quo and longstanding feudal structures.
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This chapter defines the conditions elements of the research model in this study (Fig. 10.1007/978-3-030-78498-0_2#Fig1 ). Therefore, Sects. 5.1–5.7 refer to some influential theories that have sought to explain differences in prosperity between countries from diverse disciplinary perspectives. Potential prosperity factors/theories can be clustered into three groups: (1) cultural and religious values; (2) institutions and economic growth; (3) environment and geography. Each of these distinct theories may contain “a grain of truth” about understanding prosperity imbalances between countries. Ideally, prosperity theories should be complementary instead of competing explanations. For example, geography and environmental theories explain how seasonal lands can provide a society and its economy better conditions to prosper. Institutional theory helps explain how institutions model social prosperity by perpetuating equality loops or by concentrating wealth. Cultural theory contributes to the understanding of the influence of cultural variables, such as religious beliefs and values, on prosperity. Yet, the relations among environment/geography, culture, institutions, and prosperity are highly complex and involve massive historical dynamics which would normally far exceed the scope of empirical research.
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This article shows that over the last three decades, competitive elections were associated with increased deforestation. Protection of forested areas provides long-term public goods, while their destruction provides short-term private goods for particular voters. Politicians facing a competitive election offer voters access to forested areas mainly for small-scale farming or commercial use of timber in exchange for electoral support. I test this theory of political deforestation using satellite generated global forest cover data and the results of over 1,000 national-level elections between 1982 and 2016. I find that countries that undergo a democratic transition lose an additional 0.8 percentage points of their forest cover each year, that years with close elections have over 1 percentage point per year higher forest cover loss compared to nonelection years, and that as the margin of victory in an election decreases by 10 points, the amount of deforestation increases by 0.7 percentage points per year. These increases are on the order of 5–10 times the average rate of forest loss globally. This suggests democratization is associated with underprovision of environmental public goods and contested elections are partially responsible for this underprovision.
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We survey the recent economics and history literature on the Chinese state to investigate its role in China's long-term socioeconomic development. We highlight three insights. First, unlike in Europe, where interstate competition helped give rise to capitalist states with high capacity, the Chinese state emerged from a different historical context. Second, the 18th- and 19th-century Chinese state does not fit into the mould of a strong and extractive Oriental despotic state as once commonly believed. By conventional measures, early modern China had a weak state. Third, state building and centre-local relations are two useful dimensions to understand development and change in China's recent history and political economy. To adapt China to a changing world, Chinese state builders embarked on a long process of state building from the late-19th century through the Republican and Communist eras. Facilitated partly by regional decentralisation, the process now sees the Chinese state playing a substantially larger role in the economy and everyday life than any previous time in history.
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The evolution of Mancur Olson's views regarding The Rise and Decline of Nations, the second of his three main books, is examined. It expands and extends to history and to the world the arguments presented in his earlier work, The Logic of Collective Action. Although Olson never abandons the idea that the accumulation of interest groups in a democratic society can lead to its economic stagnation, how this comes about and can be overcome changes somewhat by the time of his final book, Power and Prosperity, which focuses on the problems of transition economies and proper political governance. A sign of the greater complexity of his later views emerges in his analysis of the U.S. South, presented in his 1983 presidential address to the Southern Economic Association.
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Mancur Olson, professor of Economics at the University of Maryland‐College Park, died February 19, 1998. He served the Southern Economic Association as a member of the Executive Committee in 1978‐80, as President‐Elect in 1980‐81, and as President in 1981‐82. Three of his colleagues, Wallace Oates, Joe Oppenheimer, and Thomas Schelling, contributed personal essays to a memorial symposium in Public Choice Studies (No. 31, 1998), a journal published in Japanese. The Editor thanks the Japan Public Choice Society for permission to publish these contributions in English for the benefit of our readers.
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This chapter discusses the unknown future. With uncertainty, something good or bad may happen. In investment, one is often concerned with the likelihood of the latter. Then there are complicating unknown unknowns. The investments return known only ex post sums it up as for a roulette ball that has reached standstill. Economic slumps represent risk. Everyone may have been too optimistic regarding the future. Asset prices could fall sharply, particularly for stocks and fixed real assets. For SWFs, slumps may be the most important risk. Another important factor is political stability. The world became safer for investment around 1990. Still, geopolitics represents a risk that has excluded some areas from receiving investments. However, for most investors more mundane, traditional risks dominate. A further uncertainty is demographics. Resource wealth is diluted by immigration. Traditional Norwegians have few children, late in life. Newcomers have higher birth rates and are not integrated in the labor market. Higher immigrant employment rates and more successful integration seems needed for long-term success and sustainability.
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Deposits of hydrocarbons are a specific type of non-renewable natural resources. Once developed and sold, they are gone. They can be left alone for prospective future development or extracted and converted into financial assets. The more easily extractable parts are developed early. Over time, technological development increases the volume of that category. Oil resource are ‘free’, and extraction highly profitable. An oil industry may thus attract significant resources. Positive income shocks evolve in good times, with needs to save for the future. In Norway, the state has mended individual savings failure through removing income from current budgets and investing it systematically long-term. Throughout the oil age there has been significant savings and investment, till 1998 in domestic infrastructure through public budgets, and later internationally through a large SWF. With erratic hydrocarbon prices, it was risk-reducing not to leave more hydrocarbons untouched. This is underscored both by high investment returns and recent indications of fossil fuel non-sustainability.
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This article explores the role of trust in corrupt networks and networks that facilitate corruption. Specifically, we ask what is the role of particularized trust in the operation of systemic corruption? How is the basis of trust reflected in the logic of corruption and with which effects? Based on the analysis of 50 in‐depth interviews in two Mexican cities, we analyze two types of particularized trust that bind actors in informal networks: trust based on political affiliation and/or personal relationships and trust derived from complicity, or the co‐participation in illicit activities. Analysis suggests that the basis of trust and the dynamics that arise thereof have different effects on the functioning and stability of the informal networks and that these, in turn, reflect the informal governance systems in place. This article provides further empirical evidence to the central role that particularized trust plays in contexts of systemic corruption, highlighting the importance of understanding these dynamics for the design of anti‐corruption efforts.
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Modern seçime dayalı demokrasilerde siyasi parti başkanı, devlet ya da hükümet başkanı, ya da seçilmiş milletvekillerinin uzun süreli ve kalıcı olarak siyasette bulunmaları durumunu “Gedikli Siyaset” olarak adlandırıyorum. Siyasete adımını atan bir kimse öncelikle seçildiği parlamentoya bir sonraki dönem bir daha seçilebilmenin hesabını yaparak hareket eder; bir siyasi partiye başkan olarak seçilmiş siyasetçi delege hesaplarının matematiğini iyi yaparak o makamda uzun süreli ve kalıcı olmayı hedefler; seçilmiş bir devlet başkanı ya da hükümet başkanı da görev süresi konusunda anayasada bir sınırlama yoksa o makama tekrar seçilebilmeyi arzular; anayasa izin vermediği takdirde siyasi manüpülasyonlar yoluyla o makamda kalmaya çalışır, hatta daha da ileri giderek kendini “ebedi lider” ya da “yaşam boyu lider” olarak ilan etmenin yollarını arar. Özellikle demokrasi, sosyal sermaye ve ahlak yönünden zayıf olan toplumlarda siyaset tarihi bu yazdıklarımızı doğrulayacak pek çok gedikli siyasetçi örnekleriyle doludur. Devlet başkanı ya da hükümet başkanlarının, siyasi parti başkanlarının, milletvekillerinin ömür boyu kariyer siyasetçiliği yapmalarını engelleyecek bağlayıcı anayasal kurallar anayasal demokrasinin olmazsa olmaz şartlarından birisidir. İster başkanlık sistemi, ister parlamenter sistem olsun bir başkan, cumhurbaşkanı ya da başbakanın görevde kalmasının belirli bir süre (dönem) ile sınırlandırılması gerekir. Bu konuda modern demokrasilerin bir kısmında uygulama alanı bulan maksimum 2 dönem (4+4=8 yıl) kuralı uygun bir anayasal kural olarak benimsenebilir. Siyasal parti başkanları için de benzer bir anayasal kural kabul edilebilir. Yani bir siyasal parti başkanı ve parti meclisi üyelerinin en fazla iki dönem görevde kalabilecekleri kuralı kabul edilebilir. Temsilciler Meclisi’ne seçilecek (Millet Meclisi) milletvekilleri ve yerel yönetim temsilcileri (belediye başkanları) için de aynı kural benimsenebilir. Bundan yaklaşık 350 yıl öncesinde John Lilburne ve arkadaşlarının kaleme aldığı Anayasa metninde yer alan şu kuralın ana mantığının hiçbir zaman akıllardan çıkarılmaması gerekir: “V.-Aynı kişinin iktidarda uzun süre bulunmasından ortaya çıkan çeşitli rahatsızlık ve tehlikelerden kaçınmak için (…) mevcut parlamentonun hiçbir üyesi bir sonraki temsilcilik için seçilme niteliğine sahip değildir ve gelecekteki herhangi bir temsilciliğin her hangi bir üyesi kendisinden hemen sonra gelen meclise seçilme ehliyetine sahip değildir.” Tesviyeciler Hareketi Bildirgesi ( 30 Nisan 1649) Seçilmiş bir politikacının maksimum iki dönem görev yaptıktan sonra tekrar parlamentoya girmesini engelleyen açık bir anayasal tasfiye kuralı fevkalade önemlidir. John Lilburne ve arkadaşları ikinci bir döneme izin vermeyen ve görev süresini bir dönem olarak sınırlayan bir kuralı benimsemişlerdir. Tek dönem ya da iki dönem sınırlamasının her ikisinin de artıları ve eksileri vardır. Ancak doğru olan görev süresini sınırlamaya dönük bir “tesviye” (tasfiye) kuralı oluşturulmasıdır. Seçilmişler için geçerli olacak kuralın bir benzerinin belirli kilit öneme sahip kurumların başkan ve üyeleri için de geçerli olması önem taşır. Anayasa Mahkemesi başkan ve üyelerinin, üst derece mahkemelerin başkan ve üyelerinin, Merkez Bankası başkanının vs. hem seçiminin siyasetten bağımsız olması, hem de seçilen bu yöneticilerin aynı makamda uzun süre görev yapmalarını engelleyecek anayasal kurallara da ihtiyaç olduğunu düşünüyorum.
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This article introduces a novel conceptualization of democratic resilience - a two-stage process where democracies avoid democratic declines altogether or avert democratic breakdown given that such autocratization is ongoing. Drawing on the Episodes of Regime Transformation (ERT) dataset, we find that democracies have had a high level of resilience to onset of autocratization since 1900. Nevertheless, democratic resilience has become substantially weaker since the end of the Cold War. Fifty-nine episodes of sustained and substantial declines in democratic practices have occurred since 1993, leading to the unprecedented breakdown of 36 democratic regimes. Ominously, we find that once autocratization begins, only one in five democracies manage to avert breakdown. We also analyse which factors are associated with each stage of democratic resilience. The results suggest that democracies are more resilient when strong judicial constraints on the executive are present and democratic institutions were strong in the past. Conversely and adding nuance to the literature, economic development is only associated with resilience to onset of autocratization, not to resilience against breakdown once autocratization has begun.
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This paper presents cross-country evidence about the relationship between politicians’ horizon and their rent-seeking behavior. Using information from CIA’s World Factbook and from the National Elections across Democracy and Autocracy dataset, we construct variables of term limits, term length and political turnover at the top executive level. We simultaneously estimate the correlations between these three variables and corruption—measured using a corruption index—from pooled cross-sections of 137 developed and developing countries observed from 2000 to 2015. We find a positive correlation between corruption and: (i) term limits at low level of term length, (ii) term length in the absence of term limits, and (iii) political turnover. Results suggest that politicians behave best if there are no term limits and frequent elections. We also provide evidence that the downward sloping part of a U-shape relationship between political turnover and corruption previously found in empirical papers can be explained by accountability and observability technologies. Theoretical mechanisms that can explain these findings are discussed.
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The constitutional political economy (CPE) approach as developed by James Buchanan places emphasis on supermajority rules—in particular, a unanimity requirement for constitutional change. Critics argue that this approach “privileges the status quo” in two problematic ways: (1) alternatives are treated unequally, because the status quo requires a smaller coalition to be “chosen” than any other institutional arrangement selected to replace it; and (2) individuals are treated unequally, because those who happen to support the status quo have excessive power to impose their will on the larger group, implying that a minority illegitimately is privileged to block change. This is a serious and important challenge. At the same time, we argue that critics have conflated two analytically distinct issues in arguing that the CPE paradigm (and constitutionalism more generally) “privilege the status quo”. Moreover, we aim to show that in rejecting the “privileged position of the status quo”, critics must confront an equally challenging task: Providing a “measuring stick” by which the legitimacy of the status quo, and changes to it, can be judged. It is precisely skepticism regarding the possibility of providing a criterion of legitimacy that is independent of agreement that leads to the peculiar position of the status quo in Buchanan’s thought.
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Corruption is widely believed to have an adverse effect on the economic performance of a country. However, many East-and-Southeast-Asian countries either achieved or currently are achieving impressively rapid economic growth despite widespread corruption – the so-called East-Asian-Paradox. A common feature of these countries was that they were autocracies. We re-examine the corruption-growth relationship, in light of the East-Asian-Paradox. We examine the role of political regimes, in mediating corruption–growth relationship using panel data over 100 countries for the period 1984–2016. We find clear evidence that corruption–growth relationship differs by the type of political regime, and the growth-enhancing effect of corruption is more likely in autocracies than in democracies. The marginal effect analysis shows that in strongly autocratic countries, higher corruption may lead to significantly higher growth, while this is not the case in democracies. Alternatively, democracy is not good for growth if there is a high level of perceived corruption. We provide suggestive evidence that the mechanism by which corruption is growth-enhancing in autocracies is through the perceived credibility of the commitment of ruling political elites to economic freedom, thereby providing confidence to the firms to invest, leading to long-term growth.
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Uncertainty induced by various economic and non-economic factors instigates macroeconomic instability. Macroeconomic instability, further, reduces predictability of a country’s macroeconomic situation, leading to misallocation of resources, reduction in economic growth and investment. This study aims at investigating the impact of violence on macroeconomic instability in selected developing countries over the period of 1984–2016. In doing so, the study has used various dimensions of violence in order to test the size, significance and direction of each type of violence for macroeconomic instability. Macroeconomic instability index is computed by using terms of trade, inflation rate, unemployment rate and real exchange rate. For estimating the impact of violence on macroeconomic instability, we have employed system GMM technique. This empirical findings state that violence increases macroeconomic instability in selected sample of developing countries. We also report that among developing countries, low-income countries suffer more from violence in comparison to the middle-income countries. This finding is robust among all dimensions of violence taken by the study. Notably, we have found that the harmful impact of interstate violence is highest for macroeconomic instability. Our findings are robust as violence creates uncertainty which distorts investment, savings and consumption, and hence affects overall economic performance.
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This paper investigates whether politicians who have plagiarized their PhD dissertations perform worse in running their polities than those who have not committed plagiarism. We look at the Russian regional governors and document that a substantial portion of them have plagiarized PhD theses. We find a negative association between plagiarized PhD of a governor and development of infrastructure (specifically, housing construction and spread of broadband Internet) in a region, controlling for other region-level characteristics potentially affecting infrastructural development. We argue that in the Russian context, a plagiarized PhD thesis is likely to indicate that a governor both is inclined to dishonest behavior and possesses poor managerial capabilities, which should have a particularly negative effect on the performance of their regions in terms of the development of infrastructure.
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In this reply, I respond to and elaborate on the critique of my book “The Code of Capital” published in this special issue. The common thread of the critiques is the call for more theorizing of the themes the book addresses, especially the conception of state power, of resources, social relations and questions of knowledge and access to knowledge about the law, or epistemology. This reply is only a first response to issues that do require further analysis and I am hoping to follow suit on at least some of them in the near future.
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This paper examines whether autocracy is a gamble. Using robust variance tests and other analyses, we find that long-term growth varies more across autocracies than across democracies. This remains true even when richer countries are excluded from the sample. We also investigate channels, to see if the higher variance of growth outcomes across autocracies can be traced to a higher variance in investment ratios or productivity growth. Overall, the paper’s findings suggest that growth prospects are more uncertain for autocracies than democracies, and especially for closed autocracies. From the viewpoint of a domestic population, autocracy remains a gamble.
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en A common view is that verified earnings reports encourage investment through improved transparency. We lack direct evidence on this foundational proposition because researchers cannot observe counterfactuals in which a manager either (i) must remain silent about performance or (ii) can make any statement about performance they desire, even a bald‐faced lie. We experimentally manipulate whether a manager can provide information to an investor by voluntarily disclosing a verified earnings report, communicating freely via unverifiable cheap talk, or both. Our experiment involves repeated interactions between an uninformed investor with funds that, if invested, generate uncertain gains, and a trustee‐manager who observes and then divides gains after they are realized. We hypothesize and find that (i) the provision of a verified earnings report leads to higher investment compared with a world in which reporting is not possible and (ii) the provision of a verified earnings report leads to more accurate cheap talk communication than when earnings reports are unavailable. Contrary to our prediction, we find that investment when both earnings reports and cheap talk are possible is statistically indistinguishable from investment when only cheap talk communication is available. Further tests reveal that a lack of verified earnings reports leads managers to sustain a partner's investment by providing high returns to the investor while also limiting (but not completely eliminating) deceptive communication and profit‐taking. Our main conclusion is that verified earnings reports promote investment on a stand‐alone basis by improving transparency, but the effect of greater transparency from earnings reports on investment is more nuanced when earnings reports can influence the disclosure of unverifiable information. The main implication of our evidence is that the greater transparency of management behavior with verified earnings reports is not unambiguously positive because making behavior more transparent can lead managers to change their behavior. RÉSUMÉ fr Les rapports sur les résultats vérifiés accroissent‐ils les investissements? Selon une conception largement répandue, les rapports sur les résultats vérifiés encouragent les investissements, car ils accroissent la transparence. Nous ne disposons pas de données directes confirmant cette proposition de base, car les chercheurs ne peuvent pas effectuer de vérifications factuelles lorsqu'un gestionnaire : 1) n'est pas autorisé à parler de rendement ou 2) peut faire toutes les déclarations qu'il désire à propos du rendement, même s'il s'agit de mensonges éhontés. À l'aide de manipulations expérimentales, nous examinons si un gestionnaire peut fournir de l'information à un investisseur en lui transmettant volontairement un rapport sur les résultats vérifiés, en communiquant avec lui librement dans le cadre d'une discussion informelle non vérifiable, ou de ces deux façons. Notre expérience comporte des interactions répétées entre un investisseur non informé disposant de fonds qui, s'ils sont investis, génèrent des profits incertains, et un gestionnaire fiduciaire qui observe puis divise les profits réalisés. Nous prévoyons et établissons que : 1) la transmission d'un rapport sur les résultats vérifiés entraîne une hausse des investissements par rapport à une situation où une telle transmission n'est pas possible et 2) la transmission d'un tel rapport mène à des discussions informelles plus précises que lorsque ce type de rapports n'est pas fourni. Contrairement à nos prévisions, nous constatons qu'il est statistiquement impossible de distinguer le niveau d'investissements associé à la possibilité à la fois de transmettre un rapport et de discuter de façon informelle de celui associé à la seule possibilité de discussion informelle. Des tests additionnels révèlent que l'absence de rapports sur les résultats vérifiés incite les gestionnaires à soutenir les investissements d'un partenaire en générant des rendements élevés pour l'investisseur tout en limitant (sans toutefois les éliminer) les discussions fallacieuses et la prise de profit. Notre principale conclusion est qu'en soi, les rapports sur les résultats vérifiés favorisent les investissements en augmentant la transparence, mais que l'effet de cette transparence accrue sur les investissements est plus nuancé lorsque ces rapports peuvent influencer la divulgation d'information non vérifiable. La conséquence principale de nos observations est que la plus grande transparence des gestionnaires en présence de rapports sur les résultats vérifiés n'est pas entièrement positive, car la transparence accrue peut inciter les gestionnaires à modifier leurs comportements.
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This research paper is aimed at formulation of a composite Governance and Democracy Index (GDI) based on the six indicators of good governance by Kaufmann et al. (2003, 2007) to assess and evaluate the relative performances of 10 major democracies of the world for the time period of 20 years (1998 – 2017) (Base Year = 1996). In order to do so, three distinct methodologies are adopted based on the absolute values and relative changes in the observations of independent variables. The extended part of this research involves formulation of Governance, Democracy, and Emancipation Index (GDEI) which incorporates the Emancipative values.
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Money laundering is not a victimless crime. Under certain circumstances, it may lead to significant criminal violence. We analyze the specific case of money laundering in local economies. Criminal organizations invest dirty money in legal local businesses, which may lead to short-term improvements in the economy that benefit the population. Authorities with access to local information may (purposely) fail to report suspicious economic activities to specialized agencies in charge of money laundering because it is politically and economically convenient. The economic windfall generated from illicit money can eventually attract additional criminal organizations to the community, or may fragment the dominant criminal organization, endogenously increasing violence. The violence generated in no way compensates the previous economic growth. We develop theoretical insights on the conditions under which this mechanism exists, and empirically test its incidence and the magnitude of its effects, using Mexican municipalities as units of analysis.
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We analyze the economic performance of countries after a multi‐decade political ruler, defined as having been in office 20 or more years, loses power. For 37 countries experiencing such an end‐of‐reign event in the period 1971–2005, we use an event study approach to compare growth in the decade following the event with growth in pre‐event periods. The results show that event countries have below average growth in the year a long‐term political leader leaves office and that cumulative growth in the ensuing decade at best matches and at worst falls significantly short of pre‐event growth levels. Growth contractions are no different following irregular transitions than after regular transitions, suggesting our results are not explained by inadvertent post‐reign turmoil. Our results instead suggest that post‐event contractions may be shaped by deliberate efforts by long‐term leaders to concentrate power while in office and poison the post‐reign economic or political environment.
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Full-text available
All of the major religious confessions existing today have outlasted every single secular ruling regime known in human history. That observation poses an interesting puzzle for social scientists interested in institutional durability. If religions can be seen as governance institutions that organize and coordinate people’s lives, why have they outlasted secular states? Despite claims regarding the inevitability of secularization, religious institutions refuse to fade from the social landscape and in many places are thriving and expanding. I argue that the durability of religious institutions relative to secular governing regimes is related to the unique ability of religions to avoid the public choice “paradox of government” as laid out by James Buchanan. More precisely, religious institutions are more resilient because they effectively provide vital public goods, involve “citizens” in the process of governance at the local level, and provide a credible neutral arbitrator for violations of the governing covenant. A further argument is made for the efficiency of religious institutions relative to states based on the smaller deadweight losses associated with participatory governance. Finally, state-sponsored confessions expose themselves to the paradox of government and become less effective in pursuing their missions.
ResearchGate has not been able to resolve any references for this publication.
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2023-03-28 01:29:20
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http://mathhelpforum.com/calculus/27081-find-parametric-equation-line.html
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# Math Help - Find a parametric equation of a line
1. ## Find a parametric equation of a line
Find the parametric equation of the line through the point p = (0,1,2) that is parallel to the plane x+y+z=2 and perpendicular to the line x=1+t , y=1-t , z=2t.
Find the parametric equation of the line through the point $P(0,1,2)$
that is parallel to the plane $x+y+z\:=\:2$ and perpendicular to the line: . $\begin{array}{ccc}x&=&1+t \\ y&=&1-t \\ z&=&2t\end{array}$
We need only the direction vector of our line, $\vec{v}$
To be parallel to the plane, $\vec{v}$ is perpendicular to the normal vector of the plane: $\vec{n} \:=\:\langle 1,1,1\rangle$
To be perpendicular to the line, $\vec{v}$ is perpendicular to the vector $\vec{u} \:=\:\langle 1,\,-1,\,2\rangle$
Hence: . $\vec{v} \;=\;\vec{n} \times \vec{u}$
. . . Go for it!
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2015-08-04 08:04:07
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https://www.bartleby.com/solution-answer/chapter-m-problem-7re-intermediate-accounting-reporting-and-analysis-3rd-edition/9781337788281/what-will-be-the-future-value-on-december-31-2023-of-5-annual-60000-deposits-starting-on-december/88a13e19-8c54-11e9-8385-02ee952b546e
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Chapter M, Problem 7RE
### Intermediate Accounting: Reporting...
3rd Edition
James M. Wahlen + 2 others
ISBN: 9781337788281
Chapter
Section
### Intermediate Accounting: Reporting...
3rd Edition
James M. Wahlen + 2 others
ISBN: 9781337788281
Textbook Problem
1 views
# What will be the future value on December 31, 2023, of 5 annual $60,000 deposits starting on December 31, 2019, if the amounts earn 8% compounded annually? To determine Compute the future value as on December 31, 2023. Explanation Future Value: The future value is value of present amount compounded at an interest rate until a particular future date. 5 annual cash flows = n$60,000 Cash flow = C
Interest rate 8% compounded annually = i
First cash flow starts on December 31, 2019, and the 5th cash flow falls on December 31, 2023. Now, it is required to calculate the present value on December 31, 2023. Here, the cash flow occurs during the last day of each time period, hence it is an ordinary annuity.
Determine the future value ordinary annuity.
Future valueO= C×(fOn=5,i=8%</
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2019-12-15 06:31:25
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https://mathoverflow.net/questions/381270/what-is-the-direct-proof-of-the-recurrence-relation-about-lattice-path-enumerati
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# What is the direct proof of the recurrence relation about lattice path enumeration given by Bizley?
Let $$k$$ be a nonnegative integer and let $$m,n$$ be coprime positive integers. Let $$\phi_k$$ be the number of lattice paths from $$(0,0)$$ to $$(km,kn)$$ with steps $$(0,1)$$ and $$(1,0)$$ that are never rising above the line $$my=nx$$. A path having this property will be called a $$\phi$$-path. Then, $$\phi_k$$ satisfies the recurrence relation $$k(m+n)\phi_k = \sum_{j=1}^{k}\binom{j(m+n)}{jm}\phi_{k-j}$$ for all $$k \in \mathbb{Z}^+$$, as shown by Bizley (1954).
Bizley has stated that “these relations can be deduced directly by general reasoning from the geometrical properties of the paths”. However, I could not manage to obtain a combinatorial proof of this theorem.
Question: What is the direct proof of the recurrence relation mentioned above?
My first thought about this relation was that the left-hand side of the equation counts the number of the cyclical permutations of all $$\phi$$-paths from $$(0,0)$$ to $$(km,kn)$$. In his paper, Bizley defines the highest point of a lattice path as “a lattice point $$X$$ on the path such that the line of gradient $$\frac{n}{m}$$ through $$X$$ cuts the y-axis at a value of $$y$$ not less than that corresponding to any other lattice point of the path”. (It is important to note that the first point $$(0,0)$$ is regarded as not belonging to the path.) Thus, the number of the cyclical permutations of all $$\phi$$-paths may be expressed as the sum of $$t$$ times the number of all the lattice paths with exactly $$t$$ highest points for all $$t=1,2,\ldots,k$$. However, apparently the right-hand side of the equation has nothing to do with the number of the lattice paths with a specified number of highest points.
I am afraid I am missing something obvious about the geometrical properties of the $$\phi$$-paths and I would be so glad if anyone can provide a combinatorial proof or trick that I could not manage to see. Thanks for your attention in advance.
The trick is to add $$\phi_k$$ to both sides of the equation, and interpret the left hand side as counting paths with a prepended horizontal step, and one of its steps marked. Then, make the marked step the first step of a path from $$(-1, 0)$$ to $$(km, kn)$$. Let $$j$$ be minimal such that this path hits $$(jm, jn)$$ and stays below $$my = nx$$ after that. Then the steps before the meeting point, excluding the final horizontal step, form an arbitrary path counted by the binomial coefficient in the summand with index $$j$$, and the remaining steps form a path counted by $$\phi_{k-j}$$.
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2023-01-28 20:36:04
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https://socratic.org/questions/how-do-you-solve-for-x-12-2-x-3
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# How do you solve for x: 12 = -2(x+3)?
Jul 28, 2016
$x = - 9$
#### Explanation:
$12 = - 2 \left(x + 3\right)$
or
$12 = - 2 x - 6$
or
$2 x + 6 = - 12$
or
$2 \left(x + 3\right) = - 12$
or
$x + 3 = - \frac{12}{2}$
or
$x + 3 = - 6$
or
$x = - 6 - 3$
or
$x = - 9$
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2019-11-20 07:46:05
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https://formulative.io/legal/licenses
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### Legal
MIT License
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## @uirouter/angularjs (1.0.22)
The MIT License
Copyright (c) 2013-2018 The AngularUI Team, Karsten Sperling
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
## angular (1.5.6)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## angular-animate (1.5.6)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
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The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## angular-filesize-filter (0.1.3)
MIT License
Copyright (c) 2016 - 2017 Fabian Meyer
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## angular-hotkeys (1.7.0)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
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subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
## angular-jwt (0.0.9)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## angular-ui-ace (0.2.3)
The MIT License
Copyright (c) 2012 the AngularUI Team, http://angular-ui.github.com
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
## angularjs-dragula (2.0.0)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
## auth0-js (9.7.3)
The MIT License (MIT)
Copyright (c) 2015 Auth0, Inc. <support@auth0.com> (http://auth0.com)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## auth0-lock (11.10.0)
The MIT License (MIT)
Copyright (c) 2015 Auth0, Inc. <support@auth0.com> (http://auth0.com)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## autosize (4.0.2)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## brace (0.10.0)
Copyright 2013 Thorsten Lorenz.
Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
## clipboard (1.5.10)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Apache License
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TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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names, trademarks, service marks, or product names of the Licensor,
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of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
PARTICULAR PURPOSE. You are solely responsible for determining the
appropriateness of using or redistributing the Work and assume any
8. Limitation of Liability. In no event and under no legal theory,
whether in tort (including negligence), contract, or otherwise,
unless required by applicable law (such as deliberate and grossly
negligent acts) or agreed to in writing, shall any Contributor be
liable to You for damages, including any direct, indirect, special,
incidental, or consequential damages of any character arising as a
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defend, and hold each Contributor harmless for any liability
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END OF TERMS AND CONDITIONS
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## core-js (3.1.4)
Copyright (c) 2014-2019 Denis Pushkarev
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
This package is licensed under MIT:
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
--------
Version 2.0, January 2004
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
1. Definitions.
"License" shall mean the terms and conditions for use, reproduction,
and distribution as defined by Sections 1 through 9 of this document.
"Licensor" shall mean the copyright owner or entity authorized by
"Legal Entity" shall mean the union of the acting entity and all
other entities that control, are controlled by, or are under common
control with that entity. For the purposes of this definition,
"control" means (i) the power, direct or indirect, to cause the
direction or management of such entity, whether by contract or
otherwise, or (ii) ownership of fifty percent (50%) or more of the
outstanding shares, or (iii) beneficial ownership of such entity.
"You" (or "Your") shall mean an individual or Legal Entity
exercising permissions granted by this License.
"Source" form shall mean the preferred form for making modifications,
including but not limited to software source code, documentation
source, and configuration files.
"Object" form shall mean any form resulting from mechanical
transformation or translation of a Source form, including but
not limited to compiled object code, generated documentation,
and conversions to other media types.
"Work" shall mean the work of authorship, whether in Source or
copyright notice that is included in or attached to the work
(an example is provided in the Appendix below).
"Derivative Works" shall mean any work, whether in Source or Object
form, that is based on (or derived from) the Work and for which the
editorial revisions, annotations, elaborations, or other modifications
represent, as a whole, an original work of authorship. For the purposes
of this License, Derivative Works shall not include works that remain
separable from, or merely link (or bind by name) to the interfaces of,
the Work and Derivative Works thereof.
"Contribution" shall mean any work of authorship, including
the original version of the Work and any modifications or additions
to that Work or Derivative Works thereof, that is intentionally
submitted to Licensor for inclusion in the Work by the copyright owner
or by an individual or Legal Entity authorized to submit on behalf of
the copyright owner. For the purposes of this definition, "submitted"
means any form of electronic, verbal, or written communication sent
to the Licensor or its representatives, including but not limited to
communication on electronic mailing lists, source code control systems,
and issue tracking systems that are managed by, or on behalf of, the
Licensor for the purpose of discussing and improving the Work, but
excluding communication that is conspicuously marked or otherwise
designated in writing by the copyright owner as "Not a Contribution."
"Contributor" shall mean Licensor and any individual or Legal Entity
on behalf of whom a Contribution has been received by Licensor and
subsequently incorporated within the Work.
2. Grant of Copyright License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
publicly display, publicly perform, sublicense, and distribute the
Work and such Derivative Works in Source or Object form.
3. Grant of Patent License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
(except as stated in this section) patent license to make, have made,
use, offer to sell, sell, import, and otherwise transfer the Work,
where such license applies only to those patent claims licensable
by such Contributor that are necessarily infringed by their
Contribution(s) alone or by combination of their Contribution(s)
with the Work to which such Contribution(s) was submitted. If You
institute patent litigation against any entity (including a
cross-claim or counterclaim in a lawsuit) alleging that the Work
or a Contribution incorporated within the Work constitutes direct
or contributory patent infringement, then any patent licenses
granted to You under this License for that Work shall terminate
as of the date such litigation is filed.
4. Redistribution. You may reproduce and distribute copies of the
Work or Derivative Works thereof in any medium, with or without
modifications, and in Source or Object form, provided that You
meet the following conditions:
(a) You must give any other recipients of the Work or
Derivative Works a copy of this License; and
(b) You must cause any modified files to carry prominent notices
stating that You changed the files; and
(c) You must retain, in the Source form of any Derivative Works
attribution notices from the Source form of the Work,
excluding those notices that do not pertain to any part of
the Derivative Works; and
(d) If the Work includes a "NOTICE" text file as part of its
distribution, then any Derivative Works that You distribute must
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documentation, if provided along with the Derivative Works; or,
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of the NOTICE file are for informational purposes only and
notices within Derivative Works that You distribute, alongside
or as an addendum to the NOTICE text from the Work, provided
for use, reproduction, or distribution of Your modifications, or
for any such Derivative Works as a whole, provided Your use,
reproduction, and distribution of the Work otherwise complies with
the conditions stated in this License.
5. Submission of Contributions. Unless You explicitly state otherwise,
any Contribution intentionally submitted for inclusion in the Work
by You to the Licensor shall be under the terms and conditions of
Notwithstanding the above, nothing herein shall supersede or modify
the terms of any separate license agreement you may have executed
with Licensor regarding such Contributions.
names, trademarks, service marks, or product names of the Licensor,
except as required for reasonable and customary use in describing the
origin of the Work and reproducing the content of the NOTICE file.
7. Disclaimer of Warranty. Unless required by applicable law or
agreed to in writing, Licensor provides the Work (and each
Contributor provides its Contributions) on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied, including, without limitation, any warranties or conditions
of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
PARTICULAR PURPOSE. You are solely responsible for determining the
appropriateness of using or redistributing the Work and assume any
8. Limitation of Liability. In no event and under no legal theory,
whether in tort (including negligence), contract, or otherwise,
unless required by applicable law (such as deliberate and grossly
negligent acts) or agreed to in writing, shall any Contributor be
liable to You for damages, including any direct, indirect, special,
incidental, or consequential damages of any character arising as a
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the Work or Derivative Works thereof, You may choose to offer,
and charge a fee for, acceptance of support, warranty, indemnity,
or other liability obligations and/or rights consistent with this
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of any other Contributor, and only if You agree to indemnify,
defend, and hold each Contributor harmless for any liability
incurred by, or claims asserted against, such Contributor by reason
END OF TERMS AND CONDITIONS
## immutable (3.7.6)
BSD License
For Immutable JS software
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
* Neither the name Facebook nor the names of its contributors may be used to
endorse or promote products derived from this software without specific
prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
## jquery (2.1.4)
Copyright 2014 jQuery Foundation and other contributors
http://jquery.com/
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
## libphonenumber-js (1.7.22)
(The MIT License)
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
'Software'), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
## location-origin (1.1.4)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
## lodash (4.17.4)
Copyright JS Foundation and other contributors <https://js.foundation/>
Based on Underscore.js, copyright Jeremy Ashkenas,
DocumentCloud and Investigative Reporters & Editors <http://underscorejs.org/>
This software consists of voluntary contributions made by many
individuals. For exact contribution history, see the revision history
available at https://github.com/lodash/lodash
The following license applies to all parts of this software except as
documented below:
====
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
====
Copyright and related rights for sample code are waived via CC0. Sample
code is defined as all source code displayed within the prose of the
documentation.
CC0: http://creativecommons.org/publicdomain/zero/1.0/
====
Files located in the node_modules and vendor directories are externally
maintained libraries used by this software which have their own
licenses; we recommend you read them, as their terms may differ from the
terms above.
## mathjax (2.7.2)
Apache License
Version 2.0, January 2004
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
1. Definitions.
"License" shall mean the terms and conditions for use, reproduction,
and distribution as defined by Sections 1 through 9 of this document.
"Licensor" shall mean the copyright owner or entity authorized by
"Legal Entity" shall mean the union of the acting entity and all
other entities that control, are controlled by, or are under common
control with that entity. For the purposes of this definition,
"control" means (i) the power, direct or indirect, to cause the
direction or management of such entity, whether by contract or
otherwise, or (ii) ownership of fifty percent (50%) or more of the
outstanding shares, or (iii) beneficial ownership of such entity.
"You" (or "Your") shall mean an individual or Legal Entity
exercising permissions granted by this License.
"Source" form shall mean the preferred form for making modifications,
including but not limited to software source code, documentation
source, and configuration files.
"Object" form shall mean any form resulting from mechanical
transformation or translation of a Source form, including but
not limited to compiled object code, generated documentation,
and conversions to other media types.
"Work" shall mean the work of authorship, whether in Source or
copyright notice that is included in or attached to the work
(an example is provided in the Appendix below).
"Derivative Works" shall mean any work, whether in Source or Object
form, that is based on (or derived from) the Work and for which the
editorial revisions, annotations, elaborations, or other modifications
represent, as a whole, an original work of authorship. For the purposes
of this License, Derivative Works shall not include works that remain
separable from, or merely link (or bind by name) to the interfaces of,
the Work and Derivative Works thereof.
"Contribution" shall mean any work of authorship, including
the original version of the Work and any modifications or additions
to that Work or Derivative Works thereof, that is intentionally
submitted to Licensor for inclusion in the Work by the copyright owner
or by an individual or Legal Entity authorized to submit on behalf of
the copyright owner. For the purposes of this definition, "submitted"
means any form of electronic, verbal, or written communication sent
to the Licensor or its representatives, including but not limited to
communication on electronic mailing lists, source code control systems,
and issue tracking systems that are managed by, or on behalf of, the
Licensor for the purpose of discussing and improving the Work, but
excluding communication that is conspicuously marked or otherwise
designated in writing by the copyright owner as "Not a Contribution."
"Contributor" shall mean Licensor and any individual or Legal Entity
on behalf of whom a Contribution has been received by Licensor and
subsequently incorporated within the Work.
2. Grant of Copyright License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
publicly display, publicly perform, sublicense, and distribute the
Work and such Derivative Works in Source or Object form.
3. Grant of Patent License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
(except as stated in this section) patent license to make, have made,
use, offer to sell, sell, import, and otherwise transfer the Work,
where such license applies only to those patent claims licensable
by such Contributor that are necessarily infringed by their
Contribution(s) alone or by combination of their Contribution(s)
with the Work to which such Contribution(s) was submitted. If You
institute patent litigation against any entity (including a
cross-claim or counterclaim in a lawsuit) alleging that the Work
or a Contribution incorporated within the Work constitutes direct
or contributory patent infringement, then any patent licenses
granted to You under this License for that Work shall terminate
as of the date such litigation is filed.
4. Redistribution. You may reproduce and distribute copies of the
Work or Derivative Works thereof in any medium, with or without
modifications, and in Source or Object form, provided that You
meet the following conditions:
(a) You must give any other recipients of the Work or
Derivative Works a copy of this License; and
(b) You must cause any modified files to carry prominent notices
stating that You changed the files; and
(c) You must retain, in the Source form of any Derivative Works
attribution notices from the Source form of the Work,
excluding those notices that do not pertain to any part of
the Derivative Works; and
(d) If the Work includes a "NOTICE" text file as part of its
distribution, then any Derivative Works that You distribute must
within such NOTICE file, excluding those notices that do not
pertain to any part of the Derivative Works, in at least one
of the following places: within a NOTICE text file distributed
as part of the Derivative Works; within the Source form or
documentation, if provided along with the Derivative Works; or,
within a display generated by the Derivative Works, if and
wherever such third-party notices normally appear. The contents
of the NOTICE file are for informational purposes only and
notices within Derivative Works that You distribute, alongside
or as an addendum to the NOTICE text from the Work, provided
for use, reproduction, or distribution of Your modifications, or
for any such Derivative Works as a whole, provided Your use,
reproduction, and distribution of the Work otherwise complies with
the conditions stated in this License.
5. Submission of Contributions. Unless You explicitly state otherwise,
any Contribution intentionally submitted for inclusion in the Work
by You to the Licensor shall be under the terms and conditions of
Notwithstanding the above, nothing herein shall supersede or modify
the terms of any separate license agreement you may have executed
with Licensor regarding such Contributions.
names, trademarks, service marks, or product names of the Licensor,
except as required for reasonable and customary use in describing the
origin of the Work and reproducing the content of the NOTICE file.
7. Disclaimer of Warranty. Unless required by applicable law or
agreed to in writing, Licensor provides the Work (and each
Contributor provides its Contributions) on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied, including, without limitation, any warranties or conditions
of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
PARTICULAR PURPOSE. You are solely responsible for determining the
appropriateness of using or redistributing the Work and assume any
8. Limitation of Liability. In no event and under no legal theory,
whether in tort (including negligence), contract, or otherwise,
unless required by applicable law (such as deliberate and grossly
negligent acts) or agreed to in writing, shall any Contributor be
liable to You for damages, including any direct, indirect, special,
incidental, or consequential damages of any character arising as a
result of this License or out of the use or inability to use the
Work (including but not limited to damages for loss of goodwill,
work stoppage, computer failure or malfunction, or any and all
other commercial damages or losses), even if such Contributor
has been advised of the possibility of such damages.
9. Accepting Warranty or Additional Liability. While redistributing
the Work or Derivative Works thereof, You may choose to offer,
and charge a fee for, acceptance of support, warranty, indemnity,
or other liability obligations and/or rights consistent with this
License. However, in accepting such obligations, You may act only
on Your own behalf and on Your sole responsibility, not on behalf
of any other Contributor, and only if You agree to indemnify,
defend, and hold each Contributor harmless for any liability
incurred by, or claims asserted against, such Contributor by reason
END OF TERMS AND CONDITIONS
boilerplate notice, with the fields enclosed by brackets "[]"
replaced with your own identifying information. (Don't include
the brackets!) The text should be enclosed in the appropriate
comment syntax for the file format. We also recommend that a
file or class name and description of purpose be included on the
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you may not use this file except in compliance with the License.
You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
## moment (2.18.1)
Copyright (c) JS Foundation and other contributors
Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
## ngclipboard (1.1.1)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## ngcomponentrouter (2.1.0)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## nuxt (2.9.1)
MIT License
- Sebastien Chopin ([@Atinux](https://github.com/Atinux))
- Alexandre Chopin ([@alexchopin](https://github.com/alexchopin))
- Pooya Parsa ([@pi0](https://github.com/pi0))
- Clark Du ([@clarkdo](https://github.com/clarkdo))
- Jonas Galvez ([@galvez](https://github.com/galvez))
- Alexander Lichter ([@manniL](https://github.com/manniL))
- Dmitry Molotkov ([@aldarund](https://github.com/aldarund))
- Kevin Marrec ([@kevinmarrec](https://github.com/kevinmarrec))
- Pim ([@pimlie](https://github.com/pimlie))
- All the amazing contributors (https://github.com/nuxt/nuxt.js/graphs/contributors)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## papaparse (4.6.3)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
## plotly.js-cartesian-dist (1.45.0)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
# The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
## regenerator-runtime (0.13.2)
MIT License
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## rxjs (5.5.12)
Apache License
Version 2.0, January 2004
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
1. Definitions.
"License" shall mean the terms and conditions for use, reproduction,
and distribution as defined by Sections 1 through 9 of this document.
"Licensor" shall mean the copyright owner or entity authorized by
"Legal Entity" shall mean the union of the acting entity and all
other entities that control, are controlled by, or are under common
control with that entity. For the purposes of this definition,
"control" means (i) the power, direct or indirect, to cause the
direction or management of such entity, whether by contract or
otherwise, or (ii) ownership of fifty percent (50%) or more of the
outstanding shares, or (iii) beneficial ownership of such entity.
"You" (or "Your") shall mean an individual or Legal Entity
exercising permissions granted by this License.
"Source" form shall mean the preferred form for making modifications,
including but not limited to software source code, documentation
source, and configuration files.
"Object" form shall mean any form resulting from mechanical
transformation or translation of a Source form, including but
not limited to compiled object code, generated documentation,
and conversions to other media types.
"Work" shall mean the work of authorship, whether in Source or
copyright notice that is included in or attached to the work
(an example is provided in the Appendix below).
"Derivative Works" shall mean any work, whether in Source or Object
form, that is based on (or derived from) the Work and for which the
editorial revisions, annotations, elaborations, or other modifications
represent, as a whole, an original work of authorship. For the purposes
of this License, Derivative Works shall not include works that remain
separable from, or merely link (or bind by name) to the interfaces of,
the Work and Derivative Works thereof.
"Contribution" shall mean any work of authorship, including
the original version of the Work and any modifications or additions
to that Work or Derivative Works thereof, that is intentionally
submitted to Licensor for inclusion in the Work by the copyright owner
or by an individual or Legal Entity authorized to submit on behalf of
the copyright owner. For the purposes of this definition, "submitted"
means any form of electronic, verbal, or written communication sent
to the Licensor or its representatives, including but not limited to
communication on electronic mailing lists, source code control systems,
and issue tracking systems that are managed by, or on behalf of, the
Licensor for the purpose of discussing and improving the Work, but
excluding communication that is conspicuously marked or otherwise
designated in writing by the copyright owner as "Not a Contribution."
"Contributor" shall mean Licensor and any individual or Legal Entity
on behalf of whom a Contribution has been received by Licensor and
subsequently incorporated within the Work.
2. Grant of Copyright License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
publicly display, publicly perform, sublicense, and distribute the
Work and such Derivative Works in Source or Object form.
3. Grant of Patent License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
(except as stated in this section) patent license to make, have made,
use, offer to sell, sell, import, and otherwise transfer the Work,
where such license applies only to those patent claims licensable
by such Contributor that are necessarily infringed by their
Contribution(s) alone or by combination of their Contribution(s)
with the Work to which such Contribution(s) was submitted. If You
institute patent litigation against any entity (including a
cross-claim or counterclaim in a lawsuit) alleging that the Work
or a Contribution incorporated within the Work constitutes direct
or contributory patent infringement, then any patent licenses
granted to You under this License for that Work shall terminate
as of the date such litigation is filed.
4. Redistribution. You may reproduce and distribute copies of the
Work or Derivative Works thereof in any medium, with or without
modifications, and in Source or Object form, provided that You
meet the following conditions:
(a) You must give any other recipients of the Work or
Derivative Works a copy of this License; and
(b) You must cause any modified files to carry prominent notices
stating that You changed the files; and
(c) You must retain, in the Source form of any Derivative Works
attribution notices from the Source form of the Work,
excluding those notices that do not pertain to any part of
the Derivative Works; and
(d) If the Work includes a "NOTICE" text file as part of its
distribution, then any Derivative Works that You distribute must
within such NOTICE file, excluding those notices that do not
pertain to any part of the Derivative Works, in at least one
of the following places: within a NOTICE text file distributed
as part of the Derivative Works; within the Source form or
documentation, if provided along with the Derivative Works; or,
within a display generated by the Derivative Works, if and
wherever such third-party notices normally appear. The contents
of the NOTICE file are for informational purposes only and
notices within Derivative Works that You distribute, alongside
or as an addendum to the NOTICE text from the Work, provided
for use, reproduction, or distribution of Your modifications, or
for any such Derivative Works as a whole, provided Your use,
reproduction, and distribution of the Work otherwise complies with
the conditions stated in this License.
5. Submission of Contributions. Unless You explicitly state otherwise,
any Contribution intentionally submitted for inclusion in the Work
by You to the Licensor shall be under the terms and conditions of
Notwithstanding the above, nothing herein shall supersede or modify
the terms of any separate license agreement you may have executed
with Licensor regarding such Contributions.
names, trademarks, service marks, or product names of the Licensor,
except as required for reasonable and customary use in describing the
origin of the Work and reproducing the content of the NOTICE file.
7. Disclaimer of Warranty. Unless required by applicable law or
agreed to in writing, Licensor provides the Work (and each
Contributor provides its Contributions) on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied, including, without limitation, any warranties or conditions
of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
PARTICULAR PURPOSE. You are solely responsible for determining the
appropriateness of using or redistributing the Work and assume any
8. Limitation of Liability. In no event and under no legal theory,
whether in tort (including negligence), contract, or otherwise,
unless required by applicable law (such as deliberate and grossly
negligent acts) or agreed to in writing, shall any Contributor be
liable to You for damages, including any direct, indirect, special,
incidental, or consequential damages of any character arising as a
result of this License or out of the use or inability to use the
Work (including but not limited to damages for loss of goodwill,
work stoppage, computer failure or malfunction, or any and all
other commercial damages or losses), even if such Contributor
has been advised of the possibility of such damages.
9. Accepting Warranty or Additional Liability. While redistributing
the Work or Derivative Works thereof, You may choose to offer,
and charge a fee for, acceptance of support, warranty, indemnity,
or other liability obligations and/or rights consistent with this
License. However, in accepting such obligations, You may act only
on Your own behalf and on Your sole responsibility, not on behalf
of any other Contributor, and only if You agree to indemnify,
defend, and hold each Contributor harmless for any liability
incurred by, or claims asserted against, such Contributor by reason
END OF TERMS AND CONDITIONS
boilerplate notice, with the fields enclosed by brackets "[]"
replaced with your own identifying information. (Don't include
the brackets!) The text should be enclosed in the appropriate
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file or class name and description of purpose be included on the
same "printed page" as the copyright notice for easier
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you may not use this file except in compliance with the License.
You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
## showdown (1.8.5)
Showdown Copyright (c) 2007, John Fraser
<http://www.attacklab.net/>
Original Markdown copyright (c) 2004, John Gruber
<http://daringfireball.net/>
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name "Markdown" nor the names of its contributors may
be used to endorse or promote products derived from this software
without specific prior written permission.
This software is provided by the copyright holders and contributors "as
is" and any express or implied warranties, including, but not limited
to, the implied warranties of merchantability and fitness for a
particular purpose are disclaimed. In no event shall the copyright owner
or contributors be liable for any direct, indirect, incidental, special,
exemplary, or consequential damages (including, but not limited to,
procurement of substitute goods or services; loss of use, data, or
profits; or business interruption) however caused and on any theory of
liability, whether in contract, strict liability, or tort (including
negligence or otherwise) arising in any way out of the use of this
software, even if advised of the possibility of such damage.
## typed-immutable (0.0.7)
The MIT License
Copyright (c) 2015-2016, typed-immutable contributors and maintainers
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## v-lazy-image (1.3.2)
MIT License
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## vee-validate (3.0.3)
The MIT License (MIT)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
## vue (2.6.10)
The MIT License (MIT)
Copyright (c) 2013-present, Yuxi (Evan) You
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
## vue-carousel (0.18.0)
MIT License
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## vue-multiselect (2.1.3)
MIT License
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
MIT License
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
## whatwg-fetch (1.0.0)
Copyright (c) 2014-2016 GitHub, Inc.
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
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permit persons to whom the Software is furnished to do so, subject to
the following conditions:
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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2019-12-09 02:46:05
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http://www.ams.org/mathscinet-getitem?mr=1491110
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MathSciNet bibliographic data MR1491110 46L05 Arzumanian, Victor; Renault, Jean Examples of pseudogroups and their \$C\sp *\$$C\sp *$-algebras. Operator algebras and quantum field theory (Rome, 1996), 93–104, Int. Press, Cambridge, MA, 1997. Links to the journal or article are not yet available
For users without a MathSciNet license , Relay Station allows linking from MR numbers in online mathematical literature directly to electronic journals and original articles. Subscribers receive the added value of full MathSciNet reviews.
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2016-10-23 17:02:42
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http://mathhelpforum.com/calculus/66920-calculating-stopping-distance-starting-speed-constant-deceleration-print.html
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# Calculating Stopping Distance from starting speed and constant deceleration
• Jan 5th 2009, 07:30 AM
Milly_Bristol
Calculating Stopping Distance from starting speed and constant deceleration
I know this is simple but I can't remember how to do this at all! Just going over antiderivatives...
Starting speed = 55mph (straight road)
Constant deceleration = 11ft/s^2
How do I work out the stopping distance?
Thanks for any help!!
• Jan 5th 2009, 07:41 AM
skeeter
convert $v_0 = 55 \, mph$ to $ft/sec$
$v(t) = v_0 - 11t$
calculate the amount of time it takes to stop ... $t_s$
stopping distance = $\int_0^{t_s} v(t) \, dt$
note that the stopping distance is very easy to calculate with a velocity graph.
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2017-01-21 20:37:00
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https://math.stackexchange.com/questions/3202743/proving-that-a-field-extension-is-galois
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# Proving that a field extension is Galois
Okay, for an assignment I'm seeking to show that a field extension is Galois. However we never really went into detail on proving such things, at least with concrete examples, and I'm having trouble following along with what few examples I can find online. I've tried though, and here's what I've got.
Prove or disprove that $$\Bbb Q(\sqrt 3,\sqrt{11})$$ is Galois over $$\Bbb Q$$.
To show an extension is Galois, we need to show it is normal and separable. In this case, we're working in fields of characteristic $$0$$, so we have separability immediately. For normality, the extension must be algebraic (which it visibly is). Then it is sufficient to show that each irreducible polynomial in $$\Bbb Q$$ that has at least one root in $$\Bbb Q(\sqrt 3,\sqrt{11})$$ has all of its roots in there, by one of several definitions of normality.
But then the question became "how to do this"? Wikipedia did give a helpful idea: if we know the extension is separable (it is) and finite (it is), then it is normal if there exists a polynomial in the lower field, such that with its roots and the lower field as a whole we can generate the upper field.
In that light, we consider the (monic) polynomial
$$f(x) = \underbrace{(x^2 - 3)}_{min. \; poly. \\ for \; \sqrt 3}\underbrace{(x^2 - 11)}_{min. \; poly. \\ for \; \sqrt {11}}$$
Would $$\Bbb Q(\sqrt 3,\sqrt{11})$$ be the splitting field for this polynomial? And if so, is this sufficient to show the field in question is Galois over the rationals?
My main qualm with this - of course if there are other problems, point them out! - that comes to mind is that Wikipedia states it has to be irreducible over the lower field:
If $$L$$ is a finite extension of $$K$$ that is separable (for example, this is automatically satisfied if $$K$$ is finite or has characteristic zero) then the following property is also equivalent: There exists an irreducible polynomial whose roots, together with the elements of $$K$$, generate $$L$$. (One says that $$L$$ is the splitting field for the polynomial.)
My $$f$$ is obviously not irreducible - it can be factored into two nontrivial polynomials as shown. Yet a similar example for whether $$\Bbb Q(\sqrt 2, \sqrt 3)$$ is Galois over the rationals (link) itself uses a polynomial that is not irreducible. So what exactly gives there?
• You are overthinking this. Normal extensions are splitting fields of polynomials. Your field is the splitting field of $f$, so is normal. As Wikipedia says, each normal and separable extension is a splitting field of an irreducible, but so what? You don't have to find such an irreducible polynomial to see your field is normal; reducible is fine. – Lord Shark the Unknown Apr 26 at 3:34
• Hm, I see. Thanks. – Eevee Trainer Apr 26 at 3:42
• That's correct. As far as I'm aware, the simplest examples of non-Galois extensions over $\mathbb Q$ are roots of degree 3 polynomials, such as $\mathbb Q(\sqrt[3]2)$ – Don Thousand Apr 26 at 3:58
• I subscribe to the point of view of @LordSharktheUnknown, of course. Still, should you want to see what an irreducible polynomial looks like here, consider the minimal polynomial of $\sqrt{3} + \sqrt{11}$ over the rationals - in fact, it is not difficult to see that $\Bbb Q(\sqrt 3,\sqrt{11}) = \Bbb Q(\sqrt 3 + \sqrt{11})$. – Andreas Caranti Apr 26 at 12:31
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2019-08-23 16:07:25
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https://www.physicsforums.com/threads/energy-conservation.103876/
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# Homework Help: Energy conservation
1. Dec 12, 2005
### iommi0028
If Kinetic Energy is mv²/2 how come E=mc² is a valid equation.. wouldn't it have to be divided by two also because c represents a velocity? Thanks for any help.
2. Dec 12, 2005
### naeblis
the equation e = mc^2 is a fundamental relation between mass and energy. A particle of mass m has an "intrinsic rest energy" Eo given by Eo = mc^2
im not 100% on the way that they derived k = 1/2 mv^2 but i do know that its only used when relating mass velocity and kinetic energy.
the Eo is the energy a mass has with no relation to velocity or position. the c is a velocity but its a relation to the speed of light your making, in 1/2 mv^2 the velocity your relating there is that of the particle of mass m.
basically the energies in the 2 equations are not the same, and in one your relating the speed of the mass, and in the other your relating a mass to a constant [the speed of light]
hope that helps.
3. Dec 12, 2005
### daniel_i_l
the 1/2mv^2 is derived by integrating the force ma over a certain distance:
$$\int_{a}^{b}ma dx$$
Last edited: Dec 12, 2005
4. Dec 12, 2005
### iommi0028
hey thanks that really cleared things up
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2018-09-22 11:38:15
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https://dsp.stackexchange.com/questions/34464/how-fast-can-you-sweep-sinewave
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# how fast can you sweep sinewave
I am asking specifically about discrete sound signal, non dithered 16 bit 48000 Hz pcm/wav format.
My question is, how fast can you change sinewave frequency before it distort? Imagine a frequency sweep,it starts at 3000 Hz and ends at 6000 Hz, 3000 Hz full cycle sinewave at 48k sampling frequency is 16 samples long, 6000 Hz is half that, so 8 samples long...
If we do the sweep from 3k to 6K long duration,lets say one second,it will cleanly sweep from one point to another,but what is the precise limit,the threshold of how fast/short we can do this sweep before it becomes distorted?
Obviously we know its at least as long as single cycle of the lowest frequency we want to sweep,so its 16 minimum becose remember 16 samples is minimum lenght of single 3000hz cycle,but is it precisely 16 or is it longer? maybe one full cycle of starting frequency sample length(16) + same for final highest frequency(6000hz = 8) so 16 + 8?
I believe its also called "sweep rate",and sinewave frequency sweep is called "chirp",I want to know precisely the mathematics behind this to figure out where exactly this threshold is.
Also does this change depending on loudness/amplitude level? if we do the 3000 Hz to 6000 Hz sweep -6 db instead of maximum amplitude,would it make difference? considering signed 16 bit is 32768 amplitude levels,-6 db would be 16384.
I want some kind o mathematical formula that would precisely tell me exactly how many samples do I need to make shortest sweep possible at specific loudness and frequency points.So for example 3000 -> 6000 full amplitude sweep? atleast XXX samples needed! 375hz to 12000hz -12db? that be XXXXX samples minimum,you get the idea...
remember,we are talking about sweeping sinewave,not waveforms like squarewave that contain harmonics
edit Definition of distortion,when the sinewave stops being sinewave,its simple as that.For example,if you module amplitude of sinewave slowly and only one way (up or down ) then it will always be just pure clean non-distorted sinewave,but if you start changing its amplitude too fast,so its going up and then changes direction downwards per single cycle of that sine,harmonic distortion will grow from that sine,so you will have multiple tones at same time for example 1000hz sine will get 2000hz,3000hz,4000hz... overtones/partials/harmonics all from amplitude changes
same things happens with freqency change instead of amplitude change,you do it too fast,and new sinewaves(hamonics) will appear at same moment on top of the original moduleted sine.
• Define what you mean by distortion. – hotpaw2 Sep 27 '16 at 16:45
• It could also help to know what purpose do you want the sweep for. If you want to test a filter's frequency response with a narrow transition width, then you should do it slower, if you need to speed test the output of some amplifier, you could do it faster. – a concerned citizen Sep 27 '16 at 16:49
• For analog signals, the mathematical theory of changing a sine wave's frequency is considered in FM / PM Signal Modulation Theory. In short such a frequency modulated signal will have a bessel type spectra. Consult an introductory communications book for details. – Fat32 Sep 27 '16 at 18:36
To ask "how fast can you sweep a sinewave?" is to ask "How fast can you hit $\frac{F_s}{2}$?".
Because, sweeping a sinewave is equivalent to modulating it.
A sine wave looks like: $$x(n) = \sin(n 2 \pi f / F_s)$$
Let's focus on that instantaneous phase. I have put $n$ first, on purpose, to show that phase, in discrete time, is a line that departs from $0$ at a slope of $\frac{2 \pi f}{F_s}$. Even more descriptively, $2 \pi \frac{f}{F_s}$.
The sharpest slope for a given $F_s$ that can exist is at $\frac{2 \pi \frac{F_s}{2}}{F_s} = \frac{2 \pi F_s}{2 F_s} = \pi$.
Anything even slightly higher than that rate will start "catching" the sinusoid at its "past", or in other words, create aliasing.
So, how fast can you sweep a sinusoid?
Consider a cartesian plane. It's $x$ axis corresponds to time and it's $y$ axis corresponds to rate of phase change. We mark a red line on the $y$ axis at $\pi$. That's our limit. We can't cross that. The time axis changes in terms of $T_s = \frac{1}{F_s}$. So, theoretically, we could go $0 \ldots \frac{F_s}{2}$ in just one step, in just one $T_s$.
Is that going to look like a sweep?
It is going to look like a sweep, as much as a sinusoid looks like a sinusoid when it is sampled at some $\frac{F_s}{2}$. That's two samples per period and it looks exactly like a triangle and nothing like a sinusoid, but when you are sampling at $F_s$, that's the best sinusoid you can "see" at $\frac{F_s}{2}$.
This cartesian plane representation though, helps convey another point too. That is, how many frequencies did the sweep end up going through anyway? In the extreme example given above, instantaneous phase was so rapidly modified that effectively just two frequencies showed up, 0 and $\frac{F_s}{2}$. Sometimes, when you are trying to obtain the frequency response of a system, you might "miss" a part of it because your sweep is so fast that it "jumps" over the mode you should have excited.
Therefore, a more meaningful way to determine your sweep rate is to accept an average power per Hz (or frequency band) that you want your chirp to deliver and then find the rate of phase change that "allows enough samples" to deliver that power.
Hope this helps.
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2019-06-24 16:53:52
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https://www.embeddedrelated.com/blogs-4/mpat/all/all.php
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## Linear Feedback Shift Registers for the Uninitiated, Part XI: Pseudorandom Number Generation
December 20, 2017
Last time we looked at the use of LFSRs in counters and position encoders.
This time we’re going to look at pseudorandom number generation, and why you may — or may not — want to use LFSRs for this purpose.
But first — an aside:
Science Fair 1983
When I was in fourth grade, my father bought a Timex/Sinclair 1000. This was one of several personal computers introduced in 1982, along with the Commodore 64. The...
## Linear Feedback Shift Registers for the Uninitiated, Part X: Counters and Encoders
December 9, 2017
Last time we looked at LFSR output decimation and the computation of trace parity.
Today we are starting to look in detail at some applications of LFSRs, namely counters and encoders.
Counters
I mentioned counters briefly in the article on easy discrete logarithms. The idea here is that the propagation delay in an LFSR is smaller than in a counter, since the logic to compute the next LFSR state is simpler than in an ordinary counter. All you need to construct an LFSR is
## Linear Feedback Shift Registers for the Uninitiated, Part IX: Decimation, Trace Parity, and Cyclotomic Cosets
December 3, 2017
Last time we looked at matrix methods and how they can be used to analyze two important aspects of LFSRs:
• time shifts
• state recovery from LFSR output
In both cases we were able to use a finite field or bitwise approach to arrive at the same result as a matrix-based approach. The matrix approach is more expensive in terms of execution time and memory storage, but in some cases is conceptually simpler.
This article will be covering some concepts that are useful for studying the...
## Linear Feedback Shift Registers for the Uninitiated, Part VIII: Matrix Methods and State Recovery
November 21, 2017
Last time we looked at a dsPIC implementation of LFSR updates. Now we’re going to go back to basics and look at some matrix methods, which is the third approach to represent LFSRs that I mentioned in Part I. And we’re going to explore the problem of converting from LFSR output to LFSR state.
Matrices: Beloved Historical Dregs
Elwyn Berlekamp’s 1966 paper Non-Binary BCH Encoding covers some work on
## Obsolete? Yes. Still in use? Yes. How do you use it? Ummm...
In today's world of constantly changing technology, quick parts availability, and seemingly endless options, some things can't change. It isn't a big deal to wait a day or less for a computer upgrade to arrive. It seems program size increases proportionally to hard drive size. The old is discarded and replaced with the new. Hard drives can hold terrabytes and even SD cards can hold gigabytes of information.
Now, suppose a system can't be changed. It is still...
## Linear Feedback Shift Registers for the Uninitiated, Part VII: LFSR Implementations, Idiomatic C, and Compiler Explorer
November 13, 2017
The last four articles were on algorithms used to compute with finite fields and shift registers:
Today we’re going to come back down to earth and show how to implement LFSR updates on a microcontroller. We’ll also talk a little bit about something called “idiomatic C” and a neat online tool for experimenting with the C compiler.
## Lazy Properties in Python Using Descriptors
November 7, 2017
This is a bit of a side tangent from my normal at-least-vaguely-embedded-related articles, but I wanted to share a moment of enlightenment I had recently about descriptors in Python. The easiest way to explain a descriptor is a way to outsource attribute lookup and modification.
Python has a bunch of “magic” methods that are hooks into various object-oriented mechanisms that let you do all sorts of ridiculously clever things. Whether or not they’re a good idea is another...
## Android for Embedded Devices - 5 Reasons why Android is used in Embedded Devices
The embedded purists are going to hate me for this. How can you even think of using Android on an embedded system ? It’s after all a mobile phone operating system/software.
Sigh !! Yes I did not like Android to begin with, as well - for use on an Embedded System. But sometimes I think the market and needs decide what has to be used and what should not be. This is one such thing. Over the past few years, I have learned to love Android as an embedded operating system....
## Linear Feedback Shift Registers for the Uninitiated, Part VI: Sing Along with the Berlekamp-Massey Algorithm
October 18, 2017
The last two articles were on discrete logarithms in finite fields — in practical terms, how to take the state $S$ of an LFSR and its characteristic polynomial $p(x)$ and figure out how many shift steps are required to go from the state 000...001 to $S$. If we consider $S$ as a polynomial bit vector such that $S = x^k \bmod p(x)$, then this is equivalent to the task of figuring out $k$ from $S$ and $p(x)$.
This time we’re tackling something...
## Linear Feedback Shift Registers for the Uninitiated, Part V: Difficult Discrete Logarithms and Pollard's Kangaroo Method
October 1, 2017
Last time we talked about discrete logarithms which are easy when the group in question has an order which is a smooth number, namely the product of small prime factors. Just as a reminder, the goal here is to find $k$ if you are given some finite multiplicative group (or a finite field, since it has a multiplicative group) with elements $y$ and $g$, and you know you can express $y = g^k$ for some unknown integer $k$. The value $k$ is the discrete logarithm of $y$...
## VHDL tutorial - A practical example - part 2 - VHDL coding
May 27, 2011
In part 1 of this series we focused on the hardware design, including some of the VHDL definitions of the I/O characteristics of the CPLD part. In part 2, we will describe the VHDL logic of the CPLD for this design.
With any design, the first step to gather the requirements for the job at hand. From part 1 of this article, I have copied two sections that address some of the requirements for the CPLD design.
The data acquisition engine has the...
## Zebras Hate You For No Reason: Why Amdahl's Law is Misleading in a World of Cats (And Maybe in Ours Too)
February 27, 20171 comment
I’ve been wasting far too much of my free time lately on this stupid addicting game called the Kittens Game. It starts so innocently. You are a kitten in a catnip forest. Gather catnip.
And you click on Gather catnip and off you go. Soon you’re hunting unicorns and building Huts and studying Mathematics and Theology and so on. AND IT’S JUST A TEXT GAME! HTML and Javascript, that’s it, no pictures. It’s an example of an
## Analog-to-Digital Confusion: Pitfalls of Driving an ADC
Imagine the following scenario:You're a successful engineer (sounds nice, doesn't it!) working on a project with three or four circuit boards. More than even you can handle, so you give one of them over to your coworker Wayne to design. Wayne graduated two years ago from college. He's smart, he's a quick learner, and he's really fast at designing schematics and laying out circuit boards. It's just that sometimes he takes some shortcuts... but in this case the circuit board is just something...
## 10 Circuit Components You Should Know
November 27, 20111 comment
Chefs have their miscellaneous ingredients, like condensed milk, cream of tartar, and xanthan gum. As engineers, we too have quite our pick of circuits, and a good circuit designer should know what's out there. Not just the bread and butter ingredients like resistors, capacitors, op-amps, and comparators, but the miscellaneous "gadget" components as well.
Here are ten circuit components you may not have heard of, but which are occasionally quite useful.
1. Multifunction gate (
## Byte and Switch (Part 1)
Imagine for a minute you have an electromagnet, and a microcontroller, and you want to use the microcontroller to turn the electromagnet on and off. Sounds pretty typical, right?We ask this question on our interviews of entry-level electrical engineers: what do you put between the microcontroller and the electromagnet?We used to think this kind of question was too easy, but there are a surprising number of subtleties here (and maybe a surprising number of job candidates that were missing...
## Introduction to Microcontrollers - Interrupts
It's Too Soon To Talk About Interrupts!
That, at least, could be one reaction to this chapter. But over the years I've become convinced that new microcontroller programmers should understand interrupts before being introduced to any complex peripherals such as timers, UARTs, ADCs, and all the other powerful function blocks found on a modern microcontroller. Since these peripherals are commonly used with interrupts, any introduction to them that does not...
## VHDL tutorial - Creating a hierarchical design
In earlier blog entries I introduced some of the basic VHDL concepts. First, developing a function ('VHDL tutorial') and later verifying and refining it ('VHDL tutorial - part 2 - Testbench' and 'VHDL tutorial - combining clocked and sequential logic'). In this entry I will describe how to...
## Help, My Serial Data Has Been Framed: How To Handle Packets When All You Have Are Streams
Today we're going to talk about data framing and something called COBS, which will make your life easier the next time you use serial communications on an embedded system -- but first, here's a quiz:
Quick Diversion, Part I: Which of the following is the toughest area of electrical engineering? analog circuit design digital circuit design power electronics communications radiofrequency (RF) circuit design electromagnetic...
Arduino Robotics
Beginner robotics is a series of article chronicling my first autonomous robot build, Clusterbot. This build is meant to be affordable, relatively easy and instructive. The total cost of the build is around $50. 1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4. ## Data Hiding in C April 20, 201317 comments Strictly speaking, C is not an object-oriented language. Although it provides some features that fit into the object-oriented paradigm it has never had the full object-oriented focus that its successor C++ offers. C++ introduced some very useful concepts and abilities that I miss when I’m developing in ANSI C. One such concept is protected member variables and functions. When you declare a class in C++ you can also declare member variables and functions as part of that class. Often, these... ## Two jobs December 5, 201223 comments For those of you following closely embeddedrelated and the other related sites, you might have noticed that I have been less active for the last couple of months, and I will use this blog post to explain why. The main reason is that I got myself involved into a project that ended up using a better part of my cpu than I originally thought it would. I currently have two jobs: one as an electrical/dsp engineer recycled as a web publisher and the other as a parent of three kids. My job... ## October winner announced November 15, 20121 comment If you are a regular visitor of EmbeddedRelated, you are most likely aware that I have been running monthly draws lately for users of the site who are helping me to clean up the archives by rating threads in the forums section. For the month of August, the member "Cryptoman" won a iPad, and for the month of September, 10 members won$50 each.
For October, the winner of the new iPod Touch is the member with the username "hssathya".
The winner of the next draw will win...
## Behold, the New Comments System!
I have just finished implementing a new system for commenting the blogs. It uses Ajax extensively, so the page won't reload if you post a comment. And it is a 'threaded' system, which means that if you post a reply to a comment, it will be attached to it.
What do you think? I personally love it. Please go ahead and test it with a quick comment.
Although it is better to be logged in to post a comment, non-registered users can also comment, but they will have...
## Best Embedded Systems pdf Documents Out There
There are thousands of pdf documents related to Embedded Systems available online. In fact, when I do a search in Google for:
embedded systems filetype:pdf
I get 4,340,000 results! A huge mix of articles, promotional documents, theses, etc.
Out of these 4 millions+ documents, I suspect that there must be at least a few hundreds jewels that deserve to be given more visibility.
Today, I am asking for your help (again!) to build a directory of some of the most useful pdf files out...
## New Discussion Group for Users of TI ARM based MCUs
June 14, 2010
If you are a user of an ARM based TI Microcontroller, please feel free to join the new "TI ARM processors MCUs" discussion group by sending a blank email to: tiarm-subscribe@yahoogroups.com This discussion group will be moderated, so you don't have to worry about receiving more spam than you probably already get. It usually takes a few weeks for a group to gain momentum, so don't worry if the activity level is low for a little while, but make sure to join so you don't miss the good...
## New TI MCU Resource Center
April 1, 2010
I am happy to announce the publication of the new "TI MCU Resource Center" on EmbeddedRelated.com, where TI will regularly add videos and articles to keep you informed on their latest and greatest MCU related products.
To access the new section, you'll find a link in the main menu of the site at the top of the page.
## Blogs Section Now Online!
September 18, 2007
I am happy to announce that the blog section is now online.
Last week, I sent an email to all the members of EmbeddedRelated.com to ask for embedded systems experts who would be interested in blogging on the site. The response was very positive and I have selected 10 highly qualified individuals who will soon be writing here about all sorts of embedded systems related subjects. I am currently in the process of receiving their info (bio, photo, username, etc) and creating their bloggers'...
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2019-02-17 12:30:36
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https://physics.stackexchange.com/questions/223678/time-ordered-product-vs-path-integral
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# Time-ordered product vs path integral
Suppose we have the Green function $$G(k) \equiv \tag 1\int d^4x e^{ikx}\langle 0| T\left(\partial^{x}_{\mu}A^{\mu}(x)B(0)\right)|0\rangle ,$$ which in path integral approach is equal to $$\tag 2 G(k) \equiv \int d^4x e^{ikx}\int \left[\prod_{i}D\Psi_{i}\right] \partial_{\mu}^{x}A^{\mu}(x)B(0)e^{iS}.$$ Since in Eq. $(2)$ all quantities are classical, then it seems that I can rewrite in a form $$\tag 3 G(k) \equiv k_{\mu}\Pi^{\mu}(k),$$ where $$\Pi^{\mu}(k) \equiv \int d^4x e^{ikx} \int \left[\prod_{i}D\Psi_{i}\right]A^{\mu}(x)B(0)e^{iS} \equiv \int d^4x e^{ikx}\langle 0| T(A_{\mu}(x)B(0))|0\rangle.$$ But in Eq. $(1)$ $T$-ordering is present, and quantities $A, B$ are quantum operators. So I can't reduce it to Eq. $(3)$: $$T(\partial_{\mu}A^{\mu}(x)B(0)) \equiv \theta (x_{0})\partial_{\mu}A^{\mu}(x)B(0) \pm \theta (-x_{0})B(0)\partial_{\mu}A^{\mu}(x) =$$ $$=\partial_{\mu}T(A^{\mu}(x)B(0)) + \delta (x_{0})[A(0,\mathbf x), B(0)]_{\pm} \Rightarrow$$ $$G(k) \equiv k_{\mu}\Pi^{\mu}(k) \pm \int d^{3}\mathbf x e^{-i\mathbf k \cdot \mathbf x}\langle 0|[A(0, \mathbf x), B(0)]_{\pm}|0\rangle$$ But I can't see why formally Eq.$(3)$ is incorrect. Moreover, I don't understand how nonzero commutator in path integral approach may appear, since all quantities are classical, and (anti)commutators are always zero. I expect that because path integral contains information about all symmetries of a given theory, the commutators will be automatically replaced on Poisson brackets, but I don't see how.
• possible duplicate of physics.stackexchange.com/q/71987 – AccidentalFourierTransform Dec 12 '15 at 14:42
• @AccidentalFourierTransform though even if it is, this is a much more clearly written question. – David Z Dec 12 '15 at 16:06
• @DavidZ I agree. However, the other question has already been answered (in detail), so OP will find a proper answer there, with nice discussions. – AccidentalFourierTransform Dec 12 '15 at 16:32
Well, in a nutshell the issue is the following. Recall that the path integral formulation [with a $\mathbb{Z}_2$-graded (super)commutative integrand] is derived from the non-commutative operator formalism via a time-slicing procedure. This means that there is an implicit time-order prescription in the definition of the path integral, which manifests itself everytime we pull operators in and out of the path integral. In particular, this is so for a time-derivative, because a time-derivative interferes in a non-trivial way with the time-slicing procedure.
See this, this and this Phys.SE posts for related discussions.
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2019-09-22 03:49:09
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http://bozor.deviantart.com/
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# ~bozor
Boris
Profile Gallery Prints Favourites Journal
## Watchers
~atrac1990 ~Jenny28 *daxusx ~Sinistersal ~suziyy ~nanaBri ~acquamarine ~elpatrone ~nenuno ~tarunbanned ~PauloDuqueFrade ~elifcuteli ~thelfs ~Kaz-A-Mania ~thelast1uthinkof ~jianhong ~keihdra ~IS--awhcom !Monique17 ~arashicage
## deviantID
Boris
Artist | Design & Interfaces
United Kingdom
Current Residence: Southampton, UK
Favourite genre of music: Trance, House
Work, work and more work recently hence virtually nothing new added. Ill get round to it eventually once I find some spare time
***************************************
My Tutorials :
> hybrid grunge
> 2d abstract
• Mood: Hopeless
send me the points I would be very happy if you send it
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Oh, before I forget - here is a llama!
Thank you,
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Hello Akhdar
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Wow, thanks for the watch! I wanted the chance to flip through your book more but oto kiralama when I got back I couldn't find you! evden eve nakliyat Thankfully Matt let me look through the book he got from you.
Beautiful stuff!
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2013-05-20 04:50:25
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https://math.mit.edu/combin/1996sp.html
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# MIT-Harvard-MSR Combinatorics Seminar
## Schedule 1996 Spring
Organizer: Jim Propp
### Eighteenth One Day Conference on Combinatorics and Graph Theory
*SUNDAY*, February 4, 1996
10 a.m. to 4:30 p.m. at Smith College Northampton MA 01063
10:00 Ethan Coven (Wesleyan Univ.) Tiling the Integers with One Prototile Daniel Kleitman (MIT) Two Problems in Applied Graph Theory: a Vector Matching Problem, and a Shuffling Problem Lunch Emily Petrie (Merrimack College) The Symmetry Group of an Almost Perfect One-Factorization Joseph J. Rushanan (MITRE) Parallel Processing and Cayley Graphs
Our Web page site has directions to Smith College, abstracts of speakers, dates of future conferences, and other information. The address is: http://math.smith.edu/~rhaas/coneweb.html
We have received an NSF grant to support these conferences. This will allow us to provide a modest transportation allowance to those attendees who are not local.
Michael Albertson (Smith College), (413) 585-3865, albertson(at-sign)smith.smith.edu
Karen Collins (Wesleyan Univ.), (203) 685-2169, kcollins(at-sign)wesleyan.edu
Ruth Haas (Smith College), (413) 585-3872, rhaas(at-sign)smith.smith.edu
### Northeastern's Geometry-Algebra-Singularities Seminar, Monday, Feb. 5, 1:30 PM at 509 Lake Hall
Andrei Zelevinsky
Totally positive matrices and pseudo line arrangements
### Wednesday, February 7 and Friday, February 9, 4:15 p.m.; MIT, room 2-338
Andrei Okounkov (Institute for Advanced Study)
Edrei's theorem and representations of S(\infty)
Edrei's theorem describes all so-called totally positive (or Polya frequency) sequences. By definition, a sequence (a_i) is called totally positive if
\det [a_{i_p j_q}]_{1 \le p,q \le k}
for all k greater than or equal to 0 and all
i_1 < i_2 < ... < i_k,
j_1 < j_2 < ... < j_k .
Such sequences arise in approximation theory, probability, ..., and representation theory of S(\infty), U(\infty), O(\infty), Sp(\infty). Two proofs of this theorem were known: Edrei's original proof, based on results of Nevanlinna about entire functions, and the "ergodic" proof of Vershik and Kerov, based on the calculation of the asymptotics of the characters of S(n) as n goes to infinity. New methods in the representation theory of infinite-dimensional classical groups provide a new proof of Edrei's theorem as well as a remarkable simplification of the existing proofs.
### Wednesday, February 14 1, 4:15 p.m.; MIT, room 2-338
Igor Pak (Harvard)
A new bijective proof of the hook-length formula
We present a new proof of the hook-length formula for the dimension of the irreducible representation of the symmetric group. In order to do that we construct an explicit bijection between two sets of tableaux.
Those who are interested may refer to http://www.labri.u-bordeaux.fr/~betrema/pak/pak.html for definitions and nice examples.
### Friday, February 23, 4:15 p.m.; MIT, room 2-338
Morris Dworkin (Brandeis)
Factorization of the cover polynomial
Chung and Graham's cover polynomial generalizes Goldman, Joichi, and White's "factorial" rook polynomial to two variables. We factor the cover polynomial completely for Ferrers boards with either increasing or decreasing column heights. For column permuted Ferrers boards, we find a sufficient condition for its partial factorization. We apply this to column permuted "staircase boards," getting a partial factorization in terms of the column permutation, as well as a sufficient condition for complete factorization.
### Wednesday, February 28, 4:30 p.m.; MIT, room 2-338
Special Time, Joint with Lie Groups Seminar
Anatoly Vershik (Steklov Mathematical Institute)
A new version of the representation theory of Coxeter Groups and spectra of Gel'fand-Tsetlin algebras
Classical representation theory of the symmetric groups (Young, Frobenius, Schur, Weyl, von Neumann, et al.) involves from the outset the notion of Young diagrams and some nontrivial combinatorics of the Young lattice.
Since the branching rule for the irreducible representations of S_n (n=1,2,...) is described by the Young lattice, one could wonder: is it possible to find this rule a priori, i.e., before all the representation theory of S_n is constructed? For beginners, the "yes" answer would justify the introduction of the Young diagrams, whereas the experts could say that the representation theory of the symmetric groups at last (a century after its creation) becomes a part of general representation theory.
Now we can say "yes"! Using Coxeter generators, Murphy-Jusys elements, Gel'fand-Tsetlin subalgebra for the symmetric groups, its spectrum, and adding some simple arguments, we obtain a new and very natural version of this remarkable classical theory.
### Joint Brandeis-Harvard-MIT-Northeastern Colloquium, Feb. 29
4:30pm, Room 335, New Classroom Building, Northeastern University
Anatoly Vershik
Asymptotic combinatorial and geometric problems from the statistical physics point of view.
### Friday, March 1, 4:15 p.m.; MIT, room 2-338
Henry Cohn (Harvard) and Jim Propp (M.I.T.)
A limit law for constrained plane partitions
MacMahon showed that the number of plane partitions with at most n rows, at most n columns, and all parts of size at most n is equal to
n-1 n-1 n-1
------- ------- -------
| | | | | | i+j+k+2
| | | | | | --------
| | | | | | i+j+k+1
i=0 j=0 k=0
(a generalization of binomial coefficients). The problem can also be viewed as one of counting plane partitions whose solid Young diagram fits inside an n-by-n-by-n box, or as one of counting tilings of a regular hexagon of side-length n by rhombuses of side 1.
Working with Michael Larsen, we have recently shown that for n large, a "typical" tiling of the hexagon (i.e., one chosen uniformly at random from the set of all tilings with n fixed) has one sort of behavior near the boundary of the hexagon and a qualitatively different sort in the interior, where the border between the two regions is asymptotically given by the circle inscribed in the hexagon. The local behavior inside the circle varies from place to place, and we can give a formula for how it varies. Our results can be interpreted as giving an asymptotic law for the typical shape of the solid Young diagram of a constrained plane partition.
### Wednesday, March 6, 3:00 p.m.; MIT, room 2-338
(note unusual time)
Sean Carroll (M.I.T.)
Beyond matrix models: a combinatorial approach to discretized two-dimensional quantum gravity
The Feynman path integral for two-dimensional quantum gravity, which is a sum over geometries and matter configurations, can be calculated by taking the continuum limit of a discretized theory of triangulated surfaces with combinatorial data representing matter fields. I will discuss an approach to such a calculation using recursion equations in free variables. The flexibility of this method allows the computation of a number of quantities which would be difficult to compute using traditional "matrix model" approaches to these theories.
### Friday, March 8, 4:15 p.m.; MIT, room 2-338
(note change of date)
Emily Petrie (Merrimack)
The symmetry group of an almost perfect one-factorization
A perfect 1-factorization of the complete graph K2n may be defined as a partition of the edge set into 1-factors, such that the union of any two of the 1-factors is connected. When viewed this way, a natural generalization is to consider 1-factorizations of K2n where the union of any three of the 1-factors is connected. We call these almost perfect 1-factorizations. We examine the automorphism group G of such 1-factorizations. For perfect 1-factorizations on K2n, strong divisibility conditions have been established for the size of the automorphism group, depending only on n. However for other types of 1-factorizations the order of the automorphism group can be relatively large in comparison with the number of vertices 2n. We ask, what restrictions can be placed on the size of the automorphism group G in the case of an almost perfect 1-factorization?
### Wednesday, March 13, 4:15 p.m.; MIT, room 2-338
Alex Postnikov (M.I.T.)
Deformed Coxeter hyperplane arrangements
The braid or Coxeter arrangement of type A_{n-1} is the arrangement of hyperplanes in R^n given by the equations x_i - x_j = 0. We study deformations of this arrangement, i.e., hyperplane arrangements of the type
x_i - x_j = a_{ij}^1,a_{ij}^2,...,a_{ij}^k.
We calculate the number of regions and the Poincare polynomial for many arrangements of this form. In particular, we prove a conjecture by Richard Stanley that the number of regions of the arrangement in R^n given by the equations x_i - x_j = 1, i < j, is equal to the number of alternating trees on {1,2,...,n}. The number of regions and the Poincare polynomial have some interesting combinatorial and arithmetical properties. Many of the results presented here are obtained in collaboration with Richard Stanley.
### Friday, March 15, 4:15 p.m.; MIT, room 2-338
The characteristic polynomial of a rational subspace arrangement
Let A be an affine subspace arrangement in R^n, defined over the integers. We give a combinatorial interpretation of the characteristic polynomial chi(A, q) of A that is valid for sufficiently large prime values of q. This result, which generalizes a theorem of Blass and Sagan, reduces the computation of chi(A, q) to a counting problem and provides an explanation for the wealth of combinatorial results discovered in the theory of hyperplane arrangements in recent years. The basic idea appeared for the first time in 1970 in a theorem of Crapo and Rota, which unfortunately was overlooked in the later development of the theory of arrangements.
We give applications for various hyperplane arrangements. These include a simple, uniform proof of a result of Blass and Sagan about the characteristic polynomial of a Coxeter arrangement, simple derivations of the characteristic polynomials of the Shi arrangements and various generalizations and a another proof of Stanley's conjecture about the number of regions of the Linial arrangement. We also extend our method to the computation of all face numbers of a rational hyperplane arrangement.
### Northeastern Univ. - Geometry-Algebra-Singularities Seminar
Tuesday March 19 at 1 PM, at 509 Lake Hall
Boris Shapiro (U. Stockholm)
Enumeration of connected components of the intersection of two open opposite Schubert cells
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%\nopagenumbers
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%\hfuzz=3.5pt
\hsize=17truecm
\vsize=24.2truecm
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%\hoffset
\document
\define \bZ {\Bbb Z}
\topmatter
\title
On the number of connected components in the intersection of 2 open
opposite Schubert
cells in $SL_n/B$
\endtitle
\author B.~Z.~Shapiro, M.~Z.~Shapiro, A.~D.~Vainshtein
\endauthor
\affil \endaffil
\abstract We consider the space
\endabstract
\abstract
Let $T_n$ denote the group of real unitary uppertriangular matrices and
$\Delta_i,\;i=1,...,n-1$
denote the the hypersurface in $T_n$ given by vanishing of the 'principal'
$i\times i$-minor in the
right upper corner. We study the number of connected components in $\Cal C_n=T_n \setminus \bigcup_i\Delta_i$ using ideas from \cite {L} and \cite {BFZ}. At
first the
problem is reduced to a purely combinatorial question about some 'action'
on the group $T_n(\bZ_2)$
of uppertriangular matrices with $0-1$-entries. The final conjecture under
consideration is as follows.
The number $\sharp_n$ of connected components in $\Cal C_n$ equals $3\times 2^n$ for all $n\ge 5$.
(Cases $n=3$ and $n=4$ are exceptional and $\sharp_3=6$, $\sharp_4=52$.)
\endabstract
\endtopmatter
\Refs
\widestnumber \key{ShSh}
\ref \key {BFZ} \by A.~Berenstein, S.~Fomin, A,~Zelevinski
\paper Parametrizations of canonical bases and totally positive matrices
\jour preprint
\yr 1995\pages 1--98\endref
\ref \key {L} \by G.~Lusztig
\paper Total positivity in reductive groups
\inbook Lie theory and geometry: in honor of Bertram Kostant, Progress in Math
\publ Birkh\"auser\vol 123
\yr 1994
\endref
\ref \key {SS} \by B.~Z.~Shapiro, M.~Z.~Shapiro
\paper On the totally positive upper triangular matrices
\finalinfo accepted to Lin. Alg. and Appl
\endref
\endRefs
\enddocument$ ### Wednesday, March 20, 4:15 p.m.; MIT, room 2-338 Volkmar Welker (Essen, Germany) On divisor posets of affine semigroups In this talk we give a preliminary report on work on posets that occur as lower intervals in the poset defined on the elements of a sub-semigroup S of N^n by divisibility within S. By work of Laudal to compute the homology of the order complexes over k of these posets is equivalent to compute Tor_i^R(k,k) for R = k[S]. We will show how to reprove some known results about Koszul rings using these techniques and show that the complexes that occur in this context are very closely related to complexes that are associated to quotients of polynomial ring by monomials of degree 2 (e.g., Stanley-Reisner rings of posets). ### Come to the nineteenth one day conference on Combinatorics and Graph Theory Saturday, March 30, 1996; 10 a.m. to 4:30 p.m. at Smith College, Northampton MA 01063 10:00 Andrew Kotlov (Yale University) The rank and chromatic number of graphs Rodica Simion (George Washington University) Some relations between polytopes and combinatorial statistics Lunch Sheila Sundaram (University of Miami) On the homology of partitions with an even number of blocks Tamas Szonyi (Yale University) Blocking sets in projective planes *Our three year NSF grant is ending this spring. Looking at the remaining budget for the two spring conferences, we have to reduce the transportation allowance for non-local participants for the March 30th conference to$\$$40 (from the usual \$$50). We have applied for a renewal for another 3 years of grant support, and hope to hear soon from NSF.*
Our Web page site has directions to Smith College, abstracts of speakers, dates of future conferences, and other information. The address is: http://math.smith.edu/~rhaas/coneweb.html
### A SYMPOSIUM ON EXACTLY SOLUBLE MODELS IN STATISTICAL MECHANICS: HISTORICAL PERSPECTIVES AND CURRENT STATUS
MARCH 30-31, 1996 to be held at Northeastern University, Boston, MA
The purpose of the symposium is to present historical perspectives as well as to assess the current status of the field of soluble models in statistical mechanics. Invited speakers include R. J. Baxter, D. Fisher, V. F. R. Jones, L. H. Kauffman, E. H. Lieb, B. M. McCoy, J. H. H. Perk, S. Sachdev, C. A. Tracy, P. Wiegmann, and others.
There will also be a mini-poster session for contributed papers.
For further inquiries please contact fywu(at-sign)neu.edu, king(at-sign)neu.edu, or circs(at-sign)phyjj4.cas.neu.edu, or write to Ms. M McKeever, Department of Physics, Northeastern University, Boston, MA 02115.
### Wednesday, April 3, 4:15 p.m.; MIT, room 2-338
Tony Iarrobino (Northeastern)
The hook algebra
We had shown that given a natural number n, and a sequence T = (1,2,3,...,d,t_d,...,t_i,...,t_j) of integers satisfying t_d \geq t_{d+1} \geq ... \geq t_j and \Sigma t_i = n , then the lattice P(T) of partitions having diagonal lengths T is isomorphic to a product Q(T) = L_d \times ... \times L_j where each L_i is the lattice of partitions having no more than t_i-t_{i+1} rows and 1+t_{i-1}-t_i columns, under inclusion. The map D from P(T) to Q(T): P --> Q(P) arises from arranging the difference-one hooks of P having hands on the i-diagonal into parts according to the number of such hooks having a given hand.
It follows that the knowledge of Q_1(P) = Q(P) --- the difference-one hooks of P --- determines the difference-a hooks of T for all a. In this talk we define difference-a hook partitions and describe a composition Q_a(P) \times Q_b(P) --> Q_{a+b}(P) . Thus we define a "hook difference algebra" such that Q_a(P) = Q_1(P) \times ... Q_1(P) (a times). This algebra is related to the "strand map" S: Q(T) --> P(T) that is the inverse of D.
This is joint work with J. Yam\'eogo.
### APPLIED MATHEMATICS COLLOQUIUM
Monday, April 8, 1996, 4:15 p.m. M.I.T., Building 2, Room 105
Professor Rodney J. Baxter (Australian National University)
The hard hexagon model and Rogers-Ramanujanism
### Wednesday, April 10, 4:15 p.m.; MIT, room 2-338
Andrei Zelevinsky (Northeastern)
Quasicommuting families of quantum type Plucker coordinates
This is an account of a joint work with Bernard Leclerc. We consider the q-deformation of the coordinate ring of the flag variety of type A_r . This is the algebra with unit over the field of rational functions Q(q) generated by 2^{r+1}-1 generators [J] labeled by nonempty subsets J \subset [1,r+1] := {1,2, ..., r+1} , subject to the quantized Pl\"ucker relations. We refer to the generators [J] as _quantum_flag_minors_ (they can be identified with q-minors of a generic q-matrix whose row set consists of several initial rows). We say that [I] and [J] _quasicommute_ if [J][I] = q^n [I][J] for some integer n. We are concerned with the following problem motivated by the study of canonical bases for quantum groups of type A_r .
Problem A: describe all families of quasicommuting quantum flag minors.
We obtain a combinatorial criterion for quasicommutativity of two quantum flag minors [I] and [J]. As a consequence, we show that the maximal possible size of a quasicommuting family of quantum flag minors is {r+2 \choose 2}. An interesting special class of such families is in a bijection with the set of commutation classes of reduced expressions for the longest permutation w_0 \in S_{r+1}. This result leads to a natural extension of the _second_Bruhat_order_ by Manin-Schechtman.
### Friday, April 12, 4:15 p.m.; MIT, room 2-338
Ken Fan (Harvard)
Schubert varieties and short braidedness
The theorem I will prove is this: In a finite type Weyl group, an element w has the property that you can knock out any simple generator from any reduced expression and come up with another reduced expression if and only if w is sts-avoiding. I'll use this fact to exhibit a family of singular Schubert varieties.
One curious thing is that this fact depends on finite type and is not a purely braid relation fact since it isn't true in affine A_2, for instance.
### Wednesday, April 24, 4:15 p.m.; MIT, room 2-338
Glenn Tesler (U.C. San Diego)
Plethystic formulas for the Macdonald q,t-Kostka coefficients
Macdonald introduced a two parameter symmetric function basis P_\mu(x;q,t) for which various specializations of q and t yield many of the other well-established bases. The transition matrix expressing a rescaled basis J_\mu(x;q,t) in terms of a modified Schur basis s_\lambda[X(1-t)] has components denoted K_{\lambda,\mu}(q,t), and generalizes the ordinary Kostka matrix. Macdonald conjectured that K_{\lambda,mu}(q,t) are polynomials in q and t with nonnegative integer coefficients. We show that they are polynomials by determining new explicit formulas for them. These formulas separate the dependence on \mu and \lambda, and surprisingly, their structure is entirely determined by a portion of \lambda, and not at all on \mu. These formulas are themselves symmetric functions k_\gamma(x;q,t) indexed by partitions, where if we set \gamma to be \lambda with its largest row deleted, then a certain specialization B_\mu'' of x to q,t-monomials depending on \mu essentially expresses K_{\lambda,\mu}(q,t) as k_\gamma(B_\mu;q,t). The coefficients of k_gamma(x;q,t) when expressed in terms of Schur functions are Laurent polynomials in q and t, so that k_\gamma(B_\mu;q,t) is at least a Laurent polynomial, and the simple monomial denominator is easily eliminated to yield a true polynomial.
This is joint work with Adriano Garsia.
### Friday, April 26, 4:15 p.m.; MIT, room 2-338
Sinai Robins (U.C. San Diego)
The Ehrhart Polynomial of a Lattice Polytope
The problem of counting the number of lattice points inside a lattice polytope in R^n has been studied from a variety of perspectives, including the recent work of Pommersheim and Kohvanskii using toric varieties and Cappell and Shaneson using Grothendieck-Riemann-Roch. Here we show that the Ehrhart polynomial of a lattice n-simplex has a simple analytical interpretation from the perspective of function theory on the n-torus. The methods involve Poisson Summation and Fourier integrals.
We obtain closed forms for the coefficients of the Ehrhart polynomial in terms of the elementary cotangent functions. These expressions are closely related to the formulas of Cappell and Shaneson and Hirzebruch and Zagier.
This is joint work with Ricardo Diaz.
### 20th meeting of the CoNE conference, Saturday, April 27
10 a.m. to 4:30 p.m. at Smith College Northampton MA 01063
10:00 Vera Pless (University of Illinois at Chicago) Constraints on Weight in Binary Codes Problem Session by Participants Pizza Lunch!! Brenda Latka (DIMACS) Forbidden Subtournaments and Antichains Linda Lesniak (Drew University) Tough Graph Theory
*Our three year NSF grant is ending this spring. Looking at the remaining budget, we have to reduce the transportation allowance for non-local participants for the April 27th conference to $40 (from the usual$50). We have applied for a renewal for another 3 years of grant support, and hope to hear soon from NSF.*
Our Web page site has directions to Smith College, abstracts of speakers, dates of future conferences, and other information. The address is: http://math.smith.edu/~rhaas/coneweb.html
### Wednesday, May 1, 4:15 p.m.; MIT, room 2-338
Yuval Roichman (M.I.T.)
A recursive rule for Kazhdan-Lusztig characters
The Murnaghan-Nakayama rule is a most useful recursive rule for computing characters of the symmetric groups. We present a generalization of this rule to arbitrary Coxeter groups and their Hecke algebras. The classical version is obtained as a special case, and new combinatorial interpretations follow. The work is done via Kazhdan-Lusztig theory and combinatorics of Coxeter groups.
### Wednesday, May 8, 4:15 p.m.; MIT, room 2-338
Sergey Fomin (M.I.T.)
Quantum Schubert polynomials
We compute the Gromov-Witten invariants of the flag manifold using a new combinatorial construction for its quantum cohomology ring.
This is joint work with S. Gelfand and A. Postnikov. The paper is available from http://www-math.mit.edu/~fomin/papers.html
### Friday, May 17, 4:15 p.m.; MIT, room 2-338
Frank Sottile (Toronto)
Symmetries of Littlewood-Richardson coefficients for Schubert polynomials
The Littlewood-Richardson rule is a combinatorial formula for structure constants of the ring of symmetric polynomials in terms of its Schur basis:
s_\mu \cdot s_\nu = \sum_\lambda c^\lambda_{\mu\,\nu} s_\lambda.
Schubert polynomials form a basis for the ring of polynomials in infinitely many variables x_1,x_2,..., so there are similar structure constants for Schubert polynomials, which I also call Littlewood-Richardson coefficients. These generalize the classical coefficients, as every Schur polynomial in x_1,...,x_k is a Schubert polynomial. They are, however, largely unknown.
This talk will discuss recent results (obtained with Nantel Bergeron) on those coefficients which arise when multiplying a Schubert polynomial by a Schur polynomial. We show these coefficients have certain symmetries, similar to symmetries of the classical Littlewood-Richardson coefficients, which facilitates their computation. We apply these results to the enumeration of chains in the strong Bruhat order on the symmetric group.
### Wednesday, May 22, 4:15 p.m.; MIT, room 2-338
Rodney Baxter (Australian National University and Northeastern University)
Star-triangle and star-star relations in statistical mechanics
The star-triangle is the simplest form of the "Yang-Baxter" relations and plays a vital role in solvable statistical mechanical models, ensuring that transfer matrices commute.
There are models for which no star-triangle relation is known, but which satisfy a weaker "star-star" relation. These will be discussed, and it will be shown that this weaker relation is still sufficient to ensure the required commutation properties.
### Friday, May 24, 4:15 p.m.; MIT, room 2-338
Mark Shimozono (M.I.T.)
Monotonicity properties of q-analogues of Littlewood-Richardson coefficients
Certain q-analogues of Littlewood-Richardson (LR) coefficients arise naturally in the resolution of the ideal of a nilpotent conjugacy classes of matrices in a larger nilpotent conjugacy class. These polynomials may be defined using a Kostant-Heckman formula. A conjectural description is given in terms of what we call catabolizable tableaux. In the special case of tensor products of irreducibles corresponding to rectangular partitions, there is another conjectural combinatorial description using classical LR tableaux and a generalization of Lascoux, Leclerc, and Thibon's formula for the charge statistic. Monotonicity properties of these polynomials are studied using families of statistic-preserving injections. Certain compositions of these injections furnish a bijection from the LR tableaux to the catabolizables. This is joint work, part with Jerzy Weyman and part with Anatol N. Kirillov.
## Archive
All announcements since Fall 2007 are in the Google Calendar
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2020-10-29 00:54:11
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https://carlbrannen.wordpress.com/2008/01/14/consistent-histories-and-density-operator-formalism/
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Consistent Histories and Density Operator Formalism
I’ve been busy recently, mostly trying to sell an ethanol plant, and I realize that the plan was to talk about how a particle interaction could cause a force like gravity. However, I also made the New Year’s Resolution to be more professional in my physics and that would be a rather scary post. So instead, partly due to a posting of Lubos Motl, I’m going to rewrite the formalism of the Consistent Histories interpretation of quantum mechanics into my favorite formalism, that of pure density operators. This will be added to the first chapter of my book on density operator applications to elementary particles using Clifford / geometric algebra / calculus.
We will begin with a quick review of the consistent histories formalism, largely lifted from the Wikipedia article. We will then detail how the components of that formalism (which uses projection operators and a mixed density matrix) can be rewritten in terms of pure density matrices. Finally, time and space allowing, we will discuss what these things have to do with Margaret Hawton’s photon position operator in this language.
Legal stuff: Following Wikipedia’s copyright requirements for copies of their work, this blog post is licensed under a GNU Free Documentation License. It uses material from the Wikipedia article Consistent_histories. I’ve made a few minor changes intended to make the article easier to understand and I’ve clipped off the cosmology and quantum decoherence.
In quantum mechanics, the consistent histories approach is intended to give a modern interpretation of quantum mechanics, generalising the conventional Copenhagen interpretation and providing a natural interpretation of quantum cosmology. The theory is based on a consistency criterion that then allows the history of a system to be described so that the probabilities for each history obey the rules of classical probability while being consistent with the Schroedinger equation.
According to this interpretation of quantum mechanics, the purpose of a quantum mechanical theory is to predict probabilities of various alternative histories. A history $H_i$ is defined as a sequence (product) of projection operators $P_{i,j}$ at different moments of time $t_{i,j}$:
$H_i = T \prod_{j=1}^{n_i} P_{i,j}(t_{i,j})$
The symbol T indicates that the factors in the product are ordered chronologically according to their values of $t_{i,j}$: The “past” operators with smaller values of t appear towards the right side, and the “future” operators with greater values of t appear to the left.
These projection operators can correspond to any set of questions that include all possibilities. Examples might be the three projections meaning “the electron went through the left slit,” “the electron went through the right slit” and “the electron didn’t go through either slit.” One of the aims of the theory is to show that classical questions such as, “where are my keys?” are consistent. In this case one might use a very large set of projections each one specifying the location of the keys in some small region of space.
A history is a sequence of such questions, or — mathematically — the product of the corresponding projection operators. The role of quantum mechanics is to predict the probabilities of individual histories, given the known initial conditions.
Finally, the histories are required to be consistent, i.e.
$Tr(H_i\rho H_{i'}^{\dag} ) = 0$
for $i,i'$ different. Here $\rho$ represents the initial density matrix, and the operators are expressed in the Heisenberg picture. The consistency requirement allows us to postulate that the probability of the history $H_i$ is simply
$Pr(H_i) = Tr(H_i\rho H_i^{\dag})$
which guarantees that the probability of “A or B” equals the probability of “A” plus the probability of “B” minus the probability of “A and B” and so forth. …
.
Now the first thing to notice about the above interpretation of quantum mechanics is that the fundamental quantum states are not the usual state vectors (which are almost universally assumed to be the correct description of a quantum state), but instead are a density matrix. To rewrite a density matrix into pure density operator language, we need only note that arbitrary density matrices are built from statistical combinations of pure density matrices. The difference between “matrix” and “operator” is one of language only. The operator language is simply an elegant way of avoiding having to make a choice of representation of the matrices; instead of using matrices, one leaves calculations in the form of, for example, $\gamma^0, \gamma^1, \gamma^2, \gamma^3$. In the interest of not losing my readers, I will use the ugly, but more familiar, matrix notation.
The elements of a history, $P_{i,j}$ are projection operators and therefore are idempotent , i.e.: $(P_{i,j})^2 = P_{i,j}$. This is convenient because the pure density matrices are also idempotent. In the bra ket language, this follows from the normalization of the state vector. If $\langle x| |x\rangle = 1$, then the pure density matrix built from the state x, i.e. $\rho_x = |x\rangle\langle x|$ satisfies $(\rho_x)^2 = \rho_x$.
In addition to the idempotency requirement, a pure density matrix, at least in the usual state vector oriented theory, must also be Hermitian and have trace 1. The Hermitian requirement comes from the origin of density matrices from state vectors, and amounts to the fact that $(\rho_x)^{\dag} = (|x\rangle\langle x|)^{\dag} = (\langle x|)^{\dag} (|x\rangle)^{\dag}$ = $|x\rangle \langle x| = \rho_x$. The requirement that the trace be 1 amounts to a normalization requirement and arises from the way one calculates probabilities using the trace.
Primitive Idempotents
Suppose that we have a matrix that is a projection operator and happens to have a trace of 1. What does such a matrix look like? Let’s choose a representation that diagonalizes this projection operator. What will it look like? Well, since it’s diagonal, it’s really easy to compute the square of the matrix; it’s just the matrix with the diagonal elements squared. For the matrix to be idempotent, that is, for it to be a projection operator, this means that each of the complex numbers on the diagonal must also be idempotent. That is, they have to satisfy $(\rho_{kk})^2 = \rho_{kk}$. But there are only two solutions to this equation, zero and one. To get a trace of 1, there must be exactly one 1 on the diagonal, and the rest of the elements must be zero, for example, either of these two matrices would be okay:
The above two projection operators “annihilate” each other, that is, they multiply to zero. When one has two projection operators that do this, for example A and B, then their sum, A+B is also a projection operator because (A+B)^2 = A^2 + B^2 + AB + BA = A+B. Furthermore, the trace function is linear so the trace of A+B is the sum of the traces: tr(A+B) = tr(A) + tr(B). Consequently, if one has two pure density matrices such as those shown above, then their sum is not a pure density matrix cause its trace is 2 instead of 1.
The above fact suggests an alternative definition of the pure density matrices. They are just the projection operators that cannot be written as the sum of two non zero projection operators. In the mathematical language (as opposed to the words physicists prefer to use), such projection operators are called “primitive idempotents.” The “primitive” means they cannot be written as the sum of two nonzero idempotents. Maybe they chose “primitive” because mathematicians like prime numbers. (In his papers on the “measurement algebra,” Julian Schwinger calls the things that he uses to represent quantum states “elementary measurements”. These are also primitive idempotents.)
Projection Operators as Sums of Quantum States
Sticking to the example of 4×4 matrices, one might ask what are the possible values of the trace for a 4×4 matrix that is a projection operator? Another fact about projection operators is that their eigenvalues are always 0 and 1. Diagonalizing such a thing, one finds that its trace is 0, 1, 2, 3, or 4. Therefore, at least for the 4×4 matrices, any projection operator can be written as a sum of primitive idempotents.
More generally, for any sort of finite quantum spin states (like spin-3/2 or whatever), arbitrary projection operators can be written as sums over primitive idempotents. Is this true for continuous states? I’m not sure, but it doesn’t matter much. We can always use “box normalization” and do quantum mechanics in finite spaces. Maybe a reader will correct this in the comments.
When we split a projection operator into a sum over primitive idempotents we are taking advantage of the very common assumption that a quantum state is completely characterized by the values of a complete set of commuting observables. Each choice of possible quantum numbers for those obserables defines a quantum state and has a state vector associated with it. We can take these state vectors and use them to define pure density matrices and these pure density matrices will annihilate each other. If we add two of these annihilating primitive idempotents together, the result will no longer be a quantum state (at least in the usual interpretation), but it will still be a projection operator.
Thus we can think of the projection operators in the consistent histories interpretation as sums over pure density matrices. This puts the consistent histories interpretation completely in pure density matrix form. More generally, if $P_{i,j}$ can be written as the sum of n primitive idempotents, so we can write: $P_{i,j} = \rho_{i1,j} + \rho_{i2,j} + ... + \rho_{in,j}$, what we have done is broken the “histories” part of the consistent histories interpretation into pure density matrices. In this case, we end up with n times as many histories to compare as before, but the primitive idempotents are projection operators.
In short, we can recast the consistent histories interpretation into a pure density matrix or primitive idempotent interpretation. The histories built from pure density matrices each satisfy the requirements of the histories of the usual consistent histories interpretation, and the usual histories of the consistent histories interpretation can be split quite naturally into pure density matrix form.
So let’s define a history to be a sequence of pure density matrices. And to make our notation less complex, let’s look at just one history and drop the “i”. Define our history of interest as $H = \rho_n\rho_{n-1}...\rho_1\rho_0$. These pure density matrices are Hermitian and idempotent so $\rho_j^{\dag} = \rho_j$ and they square to themselves. Writing this as the trace of a product of primitive idempotents we can manipulate the product into a form with the quantum state at the beginning and end of the product:
The above consists of a product of primitive idempotents, with the same primitive idempotent at the beginning and end.
Let’s compute this product and then calculate the trace with an example from the Pauli algebra. We’ll choose the primitive idempotent to be, oh, maybe spin in the +x direction, and we’ll abbreviate the stuff in the middle (the history) as a 2×2 matrix $H_{jk}$:
The above gives what happens if we take the end state to be spin in the +x direction. We end up with a number multiplied by the primitive idempotent for spin in the +x direction.
This is a general fact about products of operators that begin and end with the same primitive idempotent; in general, the product will be a complex multiple of that primitive idempotent. In the above example, if for the end state we’d used spin in the +z direction, our answer would have been $h_{11}$ times that state. Spin in the -z direction would yield $h_{22}$ times the primitive idempotent for spin in the -z direction.
This fact raises a question. Why do we really need the trace? Since the pure density matrix at either end of the calculation has trace 1, we can instead take the answer to be the multiple of the state. We will get the same answer, but by making the calculation this way, our formalism is entirely written in operator (matrix) form. Not only are the quantum states density matrices, the histories are products of density matrices, and even the probabilities are multiples of density matrices. Thus getting rid of the trace reduces the number of mathematical objects we need; we only need operators. Now let’s discuss photons.
Hawton’s Photon Position Operator
In introductory quantum mechanics, one works with wave functions in the position space. With such a creature, one can compute a probability density, that is, a function of space that gives the probability of finding the particle at the various points in space. For example, if the wave function is $\psi(x,t)$, then the probability of finding the particle at the point $x_0$ is proportional to $|\psi(x_0,t)|^2 = \psi(x_0,t)^{\dag}\psi(x_0,t)$.
If we wish to compute the expected value of some operator Q that depends on position, we would compute the expectation value by the integral:
For a scalar valued function, one uses the position operator $\vec{x}$ for this. In Cartesian coordinates, one could make the calculation simply with (x,y,z). It turns out that this simple position operator doesn’t work for photons.
For a spin state, things get more complicated. The usual technique in QM is to choose a direction, usually z, and to split the spin states according to their spin measured in that direction. This works beautifully in the case of spin-1/2. Let $\psi_{\pm z}(x,t)$ be the wave functions for the spin up and spin down portions of a spin-1/2 state. We then define the wave function by the state vector:
To compute, for example, the average position for the wave function, we use the fact that “x” commutes with the way we have written our states. To see what is going on, let’s write it out explicitly:
In order to do the above calculation, we used the fact that we could commute the position operator “x” with our states. This happened because we were able to split the spin-1/2 states up into spin up and spin down, and these commute with position. The problem with the traditional proof that photon wave states do not exist is well explained in Hawton and Baylis’s article: Photon Position Operators and Localized Bases(2001) (page 27):
To ensure a rotationally invariant linear manifold of localized states for a system with total angular momentum quantum number $jv$, they assumed a complete set of $2j+1$ wave functions $\psi_{jm}, -j \leq m \leq j$, where $m$ is a component referenced to an external direction. While the existence of a complete set is sufficient to give a rotationally invariant manifold, it is not necessary for massless particles of spin $X > 1/2$. Massless particles with spin have only two spin states, namely those corresponding to the helicities $\pm S$. For a system of states at the coordinate origin, the orbital angular momentum vanishes and $j=S$. The states in the linear manifold are characterized by components of j not along a space-fixed direction but along the momentum direction p. For $S>1/2$, the manifold is not complete and consequently it cannot describe a state with spin quantized along an arbitrary direction. However, it can describe the allowed states with either helicity. Furthermore, since the helicity operator commutes with the generator J of rotations, the two helicity subspaces are separately rotationally invariant. Because the helicity eigenstates form a complete rotational set only for $S \leq 1/2$, it is clear why Newton’s and Wigner’s insistence on a complete rotational manifold is stronger than necessary for massless particles with $S \geq 1$.
.
The above explanation is sufficient to show how it came to be that Hawton found the photon density operator that had previously been overlooked. Complaints about her mathematics have tended to be that the resulting wave function is not as simple as desired, or that they use matrices. If we use the matrix formalism described above for the consistent histories, our probabilities will end up not as real numbers, but instead as real multiples of matrices. In such a formalism, ending up with matrix wave mechanics is quite natural.
The central problem of the photon wave function amounts to the fact that massless spin-1 quantum states have to take states that depend on the direction in which they are travelling. Hawton’s method of doing this is to eliminate the momentum dependency by rotating it out, then doing the state split, and finally rotating back to the original orientation. I will use her 2004 paper as a reference here.
Quantum mechanics is generally easier in the momentum space. For a scalar particle, the position operator in momentum space is simply an imaginary multiple of the gradient: $i\hbar\nabla$. The problem with spin-1 is that the available quantum states (and therefore the quantum numbers of spin) depend on the orientation. If momentum is directed in the +z direction, then the available choices for spin are just +z and -z.
A similar problem occurs in the left and right handed chiral halves of the standard model particles. Rather than talk about electrons with spin in the +z and -z direction, the standard model prefers right handed and left handed electrons. Thus instead of spin, what is more natural (in both photons and the elementary fermions) is helicity. And helicity, unlike spin, is preserved under rotation.
So Hawton’s method of writing a position operator in momentum space for the photon is to begin with the usual position operator, $i\hbar \nabla$, but fix the orientation problem by first adjusting the state with a rotation matrix D. After computing the position (with the gradient operator), the rotation is eliminated by using its inverse. The resulting position operator is (equation 3 in the above):
where D is a rotation matrix that “rotates the lab z axis into p,” and I’ve slightly simplified the paper’s formula by restricting to the number density normalization case.
So, can rotation matrices be written as products of pure density matrices? Of course they can! The sequence of projection operators $\rho_n \rho_{n-1}...\rho_2\rho_1$, when considered as an operator on quantum states, takes the ket $| 1\rangle$ and converts it into a complex multiple of the state $|n\rangle$. Perhaps a calculation will assist.
This property of products of pure density matrices is general, but let’s do the example using spin-1 as used for photons. To make things quick, we’ll use n=2 so there are only two pure density matrices to deal with. (Just as in the case of products of pure density matrices that begin and end with the same state, the effect of the intermediate states in a product of states is to adjust the amplitude and phase only.)
If one has an operator S that squares to unity, SS = 1, then one can quickly turn it into a projection operator by writing (1+S)/2. We can make these sorts of operators out of the usual spin-1 operators:
if we modify them by setting one of the diagonal zeros to +1 or -1. For example:
each square to +1. What we’ve done here amounts to changing the eigenvalues of the matrices from {-1, 0, +1} to {-1, -1, +1}. By doing this, we now have that (1+S’)/2 are primitive idempotents that pick out the +1 state. The resulting pure density matrix states are:
It is clear that the above have trace 1 and are projection operators. They each have two independent eigenvectors with eigenvalue 0 and one eigenvector with eigenvalue +1. These two eigenvectors are:
In the spinor language, the above vectors are the ket states that generate the two pure density matrices. It is easy to verify that the product of the above two pure density matrices:
is a matrix that takes kets of the second type and turns them into kets of the first type. Of course this is not a general rotation matrix, however, it is a matrix that is sufficient to rotate the given states from one to the other and should be equal to the task of assembling a photon position operator in the pure density matrix formalism.
While having “rotation matrices” that annihilate everything but one spin state is kind of ugly for photons, the notion is natural in the standard model where the left and right handed particles act completely differently and so projection operators are used to pick them apart when needed.
Filed under physics
3 responses to “Consistent Histories and Density Operator Formalism”
1. William
Sidenote: You don’t have to put your entire post under GFDL if you merely quote an article, just the parts that are actually from the article. (i.e. your changed/clipped article)
Anyways, back to reading the article…
2. nigel cook
“…. I realize that the plan was to talk about how a particle interaction could cause a force like gravity. However, I also made the New Year’s Resolution to be more professional in my physics and that would be a rather scary post.”
If it’s true that quantum gravity is a (relatively) simple physical interaction process (requiring simple maths and concepts to extract predictions), then in the end you don’t have much of a choice. It may turn out that there is only one way to deal with quantum gravity. You’re right that the big problem is tackling any such subject in a way that looks professional. I’m ploughing (or plowing as spelt in USA) through QFT textbooks so I can summarize the key mainstream QFT mathematics. I don’t think it is correct.
If you have a particle that is accelerated by a series of randomly occurring interactions with gravitons, the acceleration occurs as a result of a sequence of discrete impulses, like quantum leaps. Not continuous, uniform acceleration like “curvature”. So I really think that the entire mathematical formulation of GR and much of QFT is bunk: it works as a good approximation on large scales (but not too large, or the gravitons are seriously redshifted in being exchanged between receding masses in the universe). It doesn’t work on small scales, where chaotic graviton interactions cause particles to jump around more randomly. It takes a lot of graviton interactions to smooth out the chaos of quantum interactions on small scales. All of this is just ignored by GR. QFT is nearly as bad because it also uses calculus to approximate a lot of discrete events: path integrals.
If you consider a fraction of pollen grain in a high wind, it’s motion will not be a smooth acceleration but will depend on impacts of air molecules. However, a ship’s sail will average out a large number of impacts and appear to accelerate uniformly in the breeze. It’s a case that one mathematical model works on one scale, but it is only a probability formula or statistical approximation, not a 1-2-1 direct physical model of the situation.
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2021-05-16 15:50:48
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http://knot.kaist.ac.kr/2012/talk_info.php?talk_id=74
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Name Inasa Nakamura Kyoto University Session Jan 10 16:00~16:20 E11-101 Unknotting numbers of torus-covering knots A torus-covering knot is an oriented surface knot which is in the form of a covering over the standard torus. The unknotting number of an oriented surface knot $F$ is the minimal number of disjoint 1-handles necessary to deform $F$ to an unknotted surface knot by 1-handle surgery. In this talk we study unknotting numbers of torus-covering knots. In particular, we give examples of torus-covering knots with the unknotting number exactly $n$. 101-1-10/2-I_Nakamura_2012-0110.pdf
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2017-09-19 11:46:08
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https://cs.stackexchange.com/questions/50185/how-does-hassins-algorithm-for-the-restricted-shortest-path-work
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# How does Hassin's algorithm for the Restricted Shortest Path work?
I'm studying the Approximation For Restricted Shortest Path Problem paper and don't understand what he is doing. In particular, I wonder why it is important that one computes upper and lower bounds $UB$ and $LB$ on $OPT$, so that their ratio is below some constant.
The problem is to find the least-cost path from nodes $1$ to $n$ where the cumulative delay (each edge has a delay/transit time in addition to cost) is no more than some $T$.
For the restricted shortest path problem, the exact solution can be found in pseudopolynomial time $\mathcal{O}(|E|OPT)$like this.
Let $g_j(c)$ be the time of the quickest path form node $1$ to node $j$ with cumulative cost $\le c$. \begin{align*} g_1(c) & = 0, & c = 0,\ldots,OPT, \\ g_j(0) & = \infty, & j = 2,\ldots,n, \\ g_j(c) & = \min\left\{g_j(c-1), \min_{k \mid c_{kj} \le c}\left\{g_k(c-c_{kj}) + t_{kj}\right\}\right\}, & j = 2,\ldots,n; ~ c= 1,\ldots,OPT \end{align*}
So Hassin constructs a $TEST(k)$ procedure which says $YES$ if $OPT \ge k$ and $NO$ if $OPT < k(1 + \epsilon)$
He then proceeds to pick initial bounds $UB$ and $LB$ and uses the $TEST$ to refine them until $\frac{UB}{LB} = 2$. He then computes the final solution with the exact algorithm, but where each edge cost $c_{ij }$ is scaled as $\hat{c}_{ij} = \lfloor\frac{c_{ij} (n-1)}{LB\epsilon}\rfloor$. So what I would like to know is how this application of the exact algorithm is actually polynomial. I suppose that the optimal solution in this modified graph is somehow bounded, but I do not see where the ratio of $2$ comes into play.
I have one theory now, which is that the final application of the exact algorithm on the scaled costs has complexity $\mathcal{O}\left(|E| OPT\frac{(n-1)}{LB\epsilon}\right) \subseteq \mathcal{O}(|E| 2LB\frac{(n-1)}{LB\epsilon})=\mathcal{O}(|E| 2\frac{(n-1)}{\epsilon})=\mathcal{O}\left(|E|\frac{n-1}{\epsilon}\right)$ which is then polynomial in $n \le \sqrt{|E|}$ and $\epsilon$. Can anybody confirm this?
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2020-08-05 08:25:41
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https://answers.ros.org/answers/383022/revisions/
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I had the same issue with A* making NO PATH, but after tuning global costmap inflation radius and cost scaling factor (decreased the inflation radius and increased scaling factor so that global costmap doesn't show too wide cost around obstacle), the error seems to be gone. Compared to the potential map I was getting when the error was there, I can see the potential map is generated in a more reasonable way. (connecting the start and goal position and not covering the whole map!) This is just another option you can try if you are having the same error.
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2022-06-26 21:23:17
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https://www.shaalaa.com/question-bank-solutions/derivative-derivative-polynomials-trigonometric-functions-find-derivative-following-functions-it-be-understood-that-a-b-c-d-p-q-r-s-are-fixed-non-zero-constants-m-n-are-integers-x-sec-x-x-tan-x_14008
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Books Shortlist
Solution - Find the Derivative of the Following Functions (It is to Be Understood that A, B, C, D, P, Q, R and S Are Fixed Non-zero Constants and M and N Are Integers): (X + Sec X) (X – Tan X) - Derivative - Derivative of Polynomials and Trigonometric Functions
ConceptDerivative Derivative of Polynomials and Trigonometric Functions
Question
Find the derivative of the following functions (it is to be understood that abcdp, q, r and s are fixed non-zero constants and m and n are integers): (x + sec x) (x – tan x)
Solution
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Reference Material
Solution for question: Find the Derivative of the Following Functions (It is to Be Understood that A, B, C, D, P, Q, R and S Are Fixed Non-zero Constants and M and N Are Integers): (X + Sec X) (X – Tan X) concept: Derivative - Derivative of Polynomials and Trigonometric Functions. For the courses CBSE (Arts), CBSE (Commerce), CBSE (Science)
S
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2018-02-24 12:21:10
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https://math.stackexchange.com/questions/2322949/is-the-ball-of-a-reflexive-space-weakly-metrizable
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# Is the ball of a reflexive space weakly metrizable?
We know from Banach-Alaoglu that if $E^*$ is separable then the unit ball is metrizable with the weak topology.
Now is this true for reflexive spaces? I.e., if a Banach $E$ (eq. $E^*$) is reflexive, is its ball weakly-metrizable?
I suspect the answer is no. Is there an interesting counter-example?
The unit ball in $E$ is metrizable with respect to the weak topology if and only if $E^*$ is separable. You can find the proof of this theorem in Brezis Functional Analysis, Theorem 3.29
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2019-12-16 08:19:11
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https://codereview.stackexchange.com/questions/125605/check-for-palindrome-in-singly-linked-list/125687
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# Check for palindrome in singly linked list
Looking for code review, optimizations and best practices.
Node.java
class Node {
Node next;
int data;
public Node(int value) {
data = value;
}
}
Palindrome.java
public class Palindrome {
static Node reverse(Node head) {
Node prev = null;
Node current = head;
Node next;
while (current != null) {
next = current.next;
current.next = prev;
prev = current;
current = next;
}
head = prev;
return head;
}
static public boolean isPalindrome(Node head) {
Node current = head;
int length = 0;
// Get the length of the LinkedList
while (current != null) {
current = current.next;
length++;
}
// Find position of next to mid element
int mid = length % 2 == 0 ? length / 2 + 1 : length / 2 + 2;
int idx = mid;
current = head;
// Traverse to next to mid element
while (idx > 1) {
current = current.next;
idx--;
}
// Reverse right side of the List and return head of the reversed list
Node head1 = reverse(current);
boolean isPalindrome = true;
idx = length / 2;
current = head;
// Check reversed list(second half) matches with first half
while (idx > 0) {
if (current.data != head1.data) {
isPalindrome = false;
break;
}
current = current.next;
head1 = head1.next;
idx--;
}
return isPalindrome;
}
public static void main(String[] args) {
Node head = new Node(1);
head.next = new Node(2);
head.next.next = new Node(3);
head.next.next.next = new Node(2);
head.next.next.next.next = new Node(1);
System.out.println(isPalindrome(head));
}
}
• Is it possible to change the Node class? (like adding the previous element?) – Tunaki Apr 13 '16 at 19:15
• You could start out by formatting your code with consistent indentation. – PellMel Apr 13 '16 at 20:40
## 3 Answers
Your inconsistent and unconventional indentation makes your code harder to read than it should be.
Although Java accepts multiple top-level classes in the same file as long as no more than one is public, it is poor form. Every top-level class, interface, and enum should have its own file, whether public or not. Among other things, this makes it much easier to find all the classes, both for you and for the compiler.
It is a bit questionable that you're willing to destroy the list in order to test whether it's palindromic, but inasmuch as you are willing to do so, you could perform your palindrome test more efficiently. You would use two primary Node references, one that advances one position for every two that the other advances. Using the trailing reference, you would reverse the front portion of the list as you go, so that when the lead reference finds the end of the list, the trailing reference is at the midpoint, with a reference to the reversed first half already in hand. I'm sure you see how to proceed from there.
You could also consider using an auxiliary data structure to build the reverse half-list or an equivalent; in particular, pushing the nodes one by one onto a stack would have a comparable effect. This could be done in a way that does not destroy the original list.
Or on the third hand, if you were willing to change to a doubly-linked list, and especially if you were willing to represent the list itself with a separate data structure that contained a reference to the tail in addition to the reference to the head, then the palindrome test could be performed much more simply. You would just start at both ends and work towards the middle. That doesn't modify the list, either.
@PellMel already covered very nicely the various considerations for the logic of checking if the elements form a palindrome. I will focus on techniques.
### Improving Node
If the Node class is only used by Palindrome, then it would make sense to make it a static inner class, to hide from outside. This would be good encapsulation / information hiding.
The data in Node is an int, but your algorithm can easily work with anything. Consider using generics, to increase the usefulness of classes.
The data field is never reassigned, so it could be final. It's good to make fields final when you can, to avoid accidental unintended reassignments.
### Improving reverse
This method is quite nicely done, but a few improvements can make it better.
prev is an OK name, but perhaps newHead would convey better its purpose and the logic behind it.
next is only used inside the loop, so it can be declared there, instead of outside. It's recommended to declare variables in the smallest scope where they are needed, to prevent accidental misuses.
At the end of the method, you assign prev to head and return head. head is a parameter of the method, and reassigning to method parameters is not recommended. In any case, this reassignment is pointless, because you could simply return prev.
The above suggestions applied, the method becomes:
static Node reverse(Node head) {
Node newHead = null;
Node current = head;
while (current != null) {
Node next = current.next;
current.next = newHead;
newHead = current;
current = next;
}
return newHead;
}
### Improving isPalindrome
The logic of finding the length could be extracted to its own helper method. It's good to have many small methods that have a single responsibility. It increases modularity and thereby reusability. It also improves encapsulation, by hiding the variables used by the logic of the implementation. A good method name usually obviates the need for a comment to describe the logic.
Similarly, the logic of traversing until the middle can be extracted too, for the same benefits.
head1 is obviously a poor name. How about reversedSecondHalf ? Actually, a common name for a linked list iterator variable is "runner". I would recommend this writing style:
Node runner1 = head;
Node runner2 = reverse(iterateToSecondHalf(head, length));
for (int i = 0; i < length / 2; i++) {
// ...
}
But the worst part of this method is the flag variable isPalindrome. You don't need it. When you know the list is not a palindrome, instead of setting a variable to false, and crossing fingers that the rest of the method doesn't screw anything up and returns it correctly, you could just return false immediately. If the end of the loop is reached, evidently the list is a palindrome, so you can return true. No flag variable is needed.
1
static public boolean That's an unconventional order, fix to public static boolean.
2
Your algorithm seems to chop of the very last element for some reason. Also, you could rewrite it a bit:
public static boolean isPalindromeV2(Node head) {
int length = getListLength(head);
if (length < 2) {
// An empty list or a list of one node is trivially a palindrome.
// This also handles the case where 'head' is 'null'. However, you
// might want to deal with the 'null' case differently. I leave it
// to you.
return true;
}
int reversedSubListLength = length / 2;
Node auxHead = null;
for (int counter = 0; counter < reversedSubListLength; ++counter) {
Node current = head;
head = head.next;
current.next = auxHead;
auxHead = current;
}
Node finger1 = auxHead;
Node finger2 = head;
if (length % 2 == 1) {
// Once here, the list is of odd length: skip the middle element.
finger2 = finger2.next;
}
boolean isPalindrome = true;
for (int i = 0; i < reversedSubListLength; ++i) {
if (finger1.data != finger2.data) {
isPalindrome = false;
break;
}
finger1 = finger1.next;
finger2 = finger2.next;
}
// Reverse the first half of the list so that the input list is in the
// same state as it was when passed to this routine.
for (int counter = 0; counter < reversedSubListLength; ++counter) {
Node current = auxHead;
auxHead = auxHead.next;
current.next = head;
head = current;
}
return isPalindrome;
}
private static int getListLength(Node head) {
Node node = head;
int length = 0;
while (node != null) {
node = node.next;
++length;
}
return length;
}
Hope that helps.
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2020-01-19 00:34:03
|
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http://forum.delphiarea.com/viewtopic.php?f=5&t=1862
|
## CreateProcess problem?
Please discuss general Delphi programming topics here.
### CreateProcess problem?
Trying to make Games Explorer here, functionally similar to one in Vista/7 (that, honestly, fails to serve it's purpose most of the time)
I'm using CreateProcess() to launch the game executable (or anything else for that matter).
Code: Select all
function LaunchTarget(Target: string): BOOL;var SI: TStartupInfo; PI: TProcessInformation;begin ZeroMemory(@SI, SizeOf(SI)); SI.cb := SizeOf(SI); ZeroMemory(@PI, SizeOf(PI)); Result := CreateProcess(nil, PChar(Target), nil, nil, false, 0, nil, PChar(ExtractFilePath(Target)), SI, PI);end;
Most games work this way. One does not. When it's run from Windows Explorer (e.g., directly or using a shortcut), everything is ok.
When run from my program, using the code above, it crashes.
Could it be that my CreateProcess code is wrong?
cralias
Member
Posts: 4
Joined: August 25th, 2010, 10:20 pm
Location: Latvia
### Re: CreateProcess problem?
Recently I had a similar problem with CreateProcess. The application that I wanted to execute needed elevation, and CreateProcess couldn't run it.
I used ShellExecuteEx and then all was fine.
Kambiz
Kambiz
Posts: 2424
Joined: March 7th, 2003, 7:10 pm
### Re: CreateProcess problem?
Finally got to it. I have dug so far that it was a problem with Games for Windows Live taking a dislike and updating the game itself solves it. Protection against piracy up to the teeth, so to speak.
Anyway, I'll use more powerful ShellExecuteEx from now on, more useful for my purpose. I was just about to look for how to get the default program for opening files. Thanks.
cralias
Member
Posts: 4
Joined: August 25th, 2010, 10:20 pm
Location: Latvia
### Who is online
Users browsing this forum: Bing [Bot] and 1 guest
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2018-12-10 11:16:12
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https://bookdown.org/bkrauth/BOOK/introduction.html
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# Chapter 1 Introduction
Chapter goals
In this chapter we will:
• Review educational goals and establish course expectations
• Gather resources and tools, including all needed computer software.
## 1.1 Course goals and context
ECON 233 is the first course in the two-course econometrics sequence that is required for all economics majors. If you’ve never seen the word before, “econometrics” just means statistics and data analysis for economics.
Course goals
By the end of this course:
You will develop computer skills:
1. Clean and analyze data in Excel.
2. Analyze and graph data in R.
3. Follow recomended practices for data management and reproducible analysis.
You will become familiar with basic statistical concepts:
1. Calculate and interpret probabilities and expected values.
2. Explain the relationship between population and sample.
3. Describe the properties of a statistic or estimator including its probability distribution, expected value, variance, bias, and mean squared error.
4. State and apply the law of large numbers and central limit theorem.
You will be able to apply these skills in combination to analyze real-world economic data:
1. Construct and interpret common charts including histograms, scatter plots, and time-series plots.
2. Construct and interpret freqency tables and cross-tabulations.
3. Construct and interpret common univariate and bivariate statistics, including mean, variance, standard deviation, covariance and correlation.
4. Construct and interpret hypothesis tests and confidence intervals.
We will be switching back and forth between theory, data analysis and applications. All three skill sets are valuable.
Hopefully you are in this course because you are fascinated by the course material, and would take it even if it wasn’t required for the economics major. But that isn’t the case for many of you, so I’d like to motivate everyone to take this course as an opportunity to learn some very useful skills.
Today’s world is awash in data:
• retailers maintain databases of transactions
• manufacturers track product quality and costs
• marketers collect data on customers and potential customers
• government records everyone’s interactions with schools, tax authorities, social welfare, healthcare and criminal justice,
• employers maintain detailed personnel records.
These databases can be linked and analyzed in various ways, and many of the world’s most successful companies rely heavily on the innovative gathering and usage of data:
• Google’s core product (the search engine) is built on the innovative analysis of massive amounts of data.
• Both Google and the major social media companies are based on providing valuable “free” services in order to gather data on consumers that can then be sold (in some form) to other businesses.
• Amazon and other retailers use what is called A/B testing to fine-tune product descriptions and set prices so as to maximize profits.
Some of this data analysis is done by computer scientists, but much of it is done by economists: for example, Amazon is the second-largest employer of PhD economists in the US (after the Federal Reserve System).
I always tell students thinking about the future to remember supply and demand in the labour market. In the labour market your skills and effort are the product, and you are the seller. Like all sellers, you want to be expensive. This requires that you have skills that are:
• Useful (high demand)
• Uncommon (low supply)
The ability to analyze data in a sophisticated way, and to explain the results in written or oral presentation, is an extremely useful and uncommon skill. Most of you do not have the technical skills of your colleagues in Computer Science, but if you can combine a reasonable level of computer skills with writing, knowledge of the underlying statistical principles, and the ability to recognize the economic considerations in a situation, you will do quite well.
All economics majors have the option of taking ECON 233 or BUS 232, so you may be wondering what the difference is. Either course is suitable preparation for ECON 333, but there are some key differences:
• Tools: ECON 233 uses both Excel and R, while BUS 232 uses Excel.
• You are likely to use R in ECON 333 and other upper-division ECON courses, so it is nice to get used to it now.
• Applications: ECON 233 emphasizes economics applications, while BUS 232 emphasizes business applications.
ECON 233 is part of the Social Data and Analytics (SDA) minor; if you are an economics student and are interested in that minor you are recommended to take ECON 233.
Related courses
ECON 333 is the second course in the two-course econometrics sequence requirred for all economics majors. In ECON 333, you will learn more advanced techniques including linear regression, you will use R more extensively, and you will go deeper into the theory.
If you find you enjoy and/or do well in this course, I would strongly encourage you to take further courses in econometrics:
I would also encourage you to take courses outside of the economics department, and to consider a Statistics minor or the new interdisciplinary Social Data Analytics (SDA) minor .
## 1.2 Organization and expectations
The course Canvas page is available at https://canvas.sfu.ca/courses/59191. It includes information on lectures, tutorials, quizzes, and assignments.
The course is constructed under the assumptions that:
• You have taken introductory microeconomics (ECON 103 at SFU) and introductory macroeconomics (ECON 105 at SFU). We will use ideas from those courses in applications and examples.
• You have seen some probability and statistics content in high school, though you may not remember much.
• You can do high-school level math including algebra and basic set theory and have taken or are currently taken an introductory calculus course.
• You have access to a desktop or laptop computer, and basic computer skills.
This is not a class in introductory economics, high school math, or basic computer skills. If you are a little behind in those skills you will need to ask for help, but I am happy to help anyone who asks.
## 1.3 Computer resources
To do the computer work you will need a computer with internet access and the following software packages installed:
• Microsoft Excel
• R
• RStudio
The required software packages are available free of charge for SFU students. They are also installed on all campus lab computers,
I will teach the course using Windows, and can provide technical support for Windows. All of the necessary tools are also available for macOS, but my ability to provide technical support is more limited. I’ll do the best I can.
### 1.3.1 Installing Microsoft Excel
Microsoft Excel is a well-known spreadsheet program that is available for both Windows and macOS. Alternatives to Excel include Google Sheets and Apple Numbers.
SFU has a licensing agreement with Microsoft that allows its students free installation of the entire Microsoft Office suite, including Excel. Installation instructions are available at
Once you have installed Excel, you should confirm that it is working by starting the program. You should see something that looks like this:
### 1.3.2 Installing R and RStudio
Later in the semester, we will also be using a more specialized statistical program called R, and a related program called RStudio.
• R is a programming language used for statistical analysis.
• RStudio is an “Integrated Development Environment” for R, that is it is an integrated set of tools for building and running R programs.
Both R and RStudio are open-source, and are available free of charge for both Windows and macOS. Installation instructions are available at:
NOTE: install R first, then RStudio.
After installing R and RStudio, you should confirm that they are working by opening RStudio. You should see something like this:
### 1.3.3 Installing the Tidyverse package for R
One of the most useful features of R is that it allows users to write and distribute packages that extend its capabilities.
One of the most popular and useful packages is called the Tidyverse. R is a very powerful program, but it is also a very old one: the underlying language (called “S”) was originally created in 1976. The result of this is that some of the original commands are outdated in design and aren’t well suited for modern capabilities or principles of software development. The Tidyverse solves this problem by adding new, more modern versions of these commands. You can learn more about the Tidyverse at https://www.tidyverse.org/.
To install the Tidyverse package:
1. Open RStudio if it isn’t already open.
2. Click in the Console window (you will see it towards the bottom of the screen)
3. Enter install.packages("tidyverse") (i.e., type it and hit the <enter> key)
Once the installation is concluded and the > prompt reappears you can test to make sure the installation worked.
1. Enter library(tidyverse) in the console window.
• If you don’t get an error message, the installation worked.
• If you get an error message, drop by office hours to get help.
If you run into trouble, don’t worry. We will not need the Tidyverse for a few weeks, so there is plenty of time to get help.
## 1.4 Conventions of this book
This book uses consistent visual conventions to convey information.
• Organization:
• Each chapter corresponds to one week of the course.
• Typography:
• Computer code or other inputs are shown like this.
• When new terminology is introduced, it is shown like this.
• Boxes:
• Pull-out information is shown in colored boxes.
Boxes like this are for examples
Boxes that look like this are for showing course or chapter goals.
Boxes like this are for providing economic background
Boxes like this are for providing optional information that might be of interest to some students.
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2021-06-14 06:37:02
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https://www.ziiai.com/project/494
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# stanfordnlp/CoreNLP
Stanford CoreNLP: A Java suite of core NLP tools.
22 次浏览
# Stanford CoreNLP
Stanford CoreNLP provides a set of natural language analysis tools written in Java. It can take raw human language text input and give the base forms of words, their parts of speech, whether they are names of companies, people, etc., normalize and interpret dates, times, and numeric quantities, mark up the structure of sentences in terms of phrases or word dependencies, and indicate which noun phrases refer to the same entities. It was originally developed for English, but now also provides varying levels of support for (Modern Standard) Arabic, (mainland) Chinese, French, German, and Spanish. Stanford CoreNLP is an integrated framework, which make it very easy to apply a bunch of language analysis tools to a piece of text. Starting from plain text, you can run all the tools with just two lines of code. Its analyses provide the foundational building blocks for higher-level and domain-specific text understanding applications. Stanford CoreNLP is a set of stable and well-tested natural language processing tools, widely used by various groups in academia, industry, and government. The tools variously use rule-based, probabilistic machine learning, and deep learning components.
The Stanford CoreNLP code is written in Java and licensed under the GNU General Public License (v3 or later). Note that this is the full GPL, which allows many free uses, but not its use in proprietary software that you distribute to others.
### Build Instructions
Several times a year we distribute a new version of the software, which corresponds to a stable commit.
During the time between releases, one can always use the latest, under development version of our code.
Here are some helpful instructions to use the latest code:
#### Provided build
Sometimes we will provide updated jars here which have the latest version of the code.
At present the current released version of the code is our most recent released jar, though you can always build the very latest from GitHub HEAD yourself.
#### Build with Ant
1. Make sure you have Ant installed, details here: http://ant.apache.org/
2. Compile the code with this command: cd CoreNLP ; ant
3. Then run this command to build a jar with the latest version of the code: cd CoreNLP/classes ; jar -cf ../stanford-corenlp.jar edu
4. This will create a new jar called stanford-corenlp.jar in the CoreNLP folder which contains the latest code
5. The dependencies that work with the latest code are in CoreNLP/lib and CoreNLP/liblocal, so make sure to include those in your CLASSPATH.
#### Build with Maven
1. Make sure you have Maven installed, details here: https://maven.apache.org/
2. If you run this command in the CoreNLP directory: mvn package , it should run the tests and build this jar file: CoreNLP/target/stanford-corenlp-3.9.2.jar
4. If you want to use Stanford CoreNLP as part of a Maven project you need to install the models jars into your Maven repository. Below is a sample command for installing the Spanish models jar. For other languages just change the language name in the command. To install stanford-corenlp-models-current.jar you will need to set -Dclassifier=models. Here is the sample command for Spanish: mvn install:install-file -Dfile=/location/of/stanford-spanish-corenlp-models-current.jar -DgroupId=edu.stanford.nlp -DartifactId=stanford-corenlp -Dversion=3.9.2 -Dclassifier=models-spanish -Dpackaging=jar
### Useful resources
You can find releases of Stanford CoreNLP on Maven Central.
You can find more explanation and documentation on the Stanford CoreNLP homepage.
The most recent models associated with the code in the HEAD of this repository can be found here.
Some of the larger (English) models -- like the shift-reduce parser and WikiDict -- are not distributed with our default models jar. The most recent version of these models can be found here.
We distribute resources for other languages as well, including Arabic models, Chinese models, French models, German models, and Spanish models.
For information about making contributions to Stanford CoreNLP, see the file CONTRIBUTING.md.
Questions about CoreNLP can either be posted on StackOverflow with the tag stanford-nlp, or on the mailing lists.
stanfordnlp
• 最近提交：2019-01-10
• 创建时间：2013-06-27
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2020-03-29 05:51:06
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https://arne.schlueter.is/working-on/earth-observation-for-journalism/sources/02d-spectral-indices.html
|
# Generalized Spectral Index Calculation¶
Elaborating on the work done in previous sections, this section contains a complete implementation of the calculation of various spectral indicators.
It does not contain code to download products from the Open Access Hub1. It is rather a re-usable notebook that can be re-used for the calculation of indices only.
The calculation in this notebook depends on three parameters:
• product_path is the path to a previously downloaded product
• index_to_calculate is one of the supported indices; these are
• BSI: Bare Soil Index
• NBR: Normalized Burn Ratio
• NDVI: Normalized Difference Vegetation Index
• NDWI: normalized Difference Water Index
The formulas for the indices below are ported from versions provided by Sentinel Hub, which implements indices listed in the Index DataBase.
When running this notebook interactively, Kernel → Restart and Run All Cells can be used to re-evaluate all cells in this notebook after configuring the pipeline. The path of the output file containing the processed values will be printed below the last cell.
from pathlib import Path
# pick one product to calculate the index for and define it as product_path
products = sorted(Path('resources/a_folder_containing_downloaded_products').glob('*.zip'))
product_path = products[0]
# pick one of the indices above
index_to_calculate = 'ndwi'
## Product Preview¶
The following lines can be uncommented to plot a true color image of the downloaded data:
#from sentinel_helpers import scihub_band_paths
#import rasterio.plot as rplot
#
#tci = scihub_band_paths(product_path, 'TCI', '60m')[0]
#with r.open(tci) as src:
# rplot.show(src)
## Define Formulas¶
Formulas are defined as data so that the bands can be substituted with actual values later on. By declaratively expressing the formula calculations computations can be executed lazily and only when needed. This is done so the formulas can be defined independent from actual data, which is needed only much later.
### Operators¶
Many spectral indicators can be expressed using band arithmetic with formulas similar to the NDVI:
$\text{NDVI} = \frac{\text{B08} - \text{B04}}{\text{B08} + \text{B04}}$
To define the index calculation formulas in this way, first the basic arithmetic operations +, -, * and / are wrapped in functions taking variadic arguments:
from functools import reduce
def add(nums):
return reduce(lambda a, b: a + b, nums)
def sub(nums):
return reduce(lambda a, b: a - b, nums)
def div(nums):
return reduce(lambda a, b: a / b, nums)
def mul(nums):
return reduce(lambda a, b: a * b, nums)
### Indices¶
These function are used to define formulas for the selection of indices mentioned in the introduction. These indices are not exhaustive - there are many spectral indices which are not implemented in this notebook. The general shape of theses formulas however allows for enough flexibility to implement other indices as well.
The formulas are defined in a lisp-like prefix notation: (add, 1, 2, 3) translates to 1 + 2 + 3. Each element in a formula can be either a function, a string or a tuple. Tuples are delimited using (). The first element of these tuples is one of the operations defined above. It is followed by at least one other element, which can be any of the following:
• Tuples, allowing the recursive expression of formulas.
• Strings, which encode band numbers.
• Constants, i.e. integers or floats.
indices = {
# normalized burn ratio
'nbr': (div, (sub, 'B08', 'B12'), (add, 'B08', 'B12')),
# normalized difference vegetation index
'ndvi': (div, (sub, 'B08', 'B04'), (add, 'B08', 'B04')),
# normalized difference water index
'ndwi': (div, (sub, 'B03', 'B08'), (add, 'B03', 'B08')),
# bare soil index
'bsi': (div, (sub, (add, 'B11', 'B04'), (add, 'B08', 'B02')),
(add, (add, 'B11', 'B04'), (add, 'B08', 'B02')))
}
An error is thrown if index_to_calculate does not mach any of the implemented indices above:
supported_indices = ', '.join(indices.keys())
assert index_to_calculate in supported_indices, f'Only the following indices are supported: {supported_indices}'
### Resolving the Formulas¶
get_bands is a function that returns all of the bands referenced in a recursive formula. This is necessary to resolve these references to actual data sets.
def get_bands(formula):
bands = set()
for element in formula:
if type(element) == tuple:
# recur for sub-formula
for band in get_bands(element):
bands.add(band)
elif type(element) == str:
bands.add(element)
return bands
The resolving process needs a band_map in the form of band_numnumpy.array. By defining the arithmetic operations like above, it can be treated like any other python function - read from the formula and called using op(args):
def evaluate_formula(band_map, formula):
op = formula[0]
args = []
for element in formula[1:]:
if type(element) == tuple:
# recur on sub-formula
args.append(evaluate_formula(band_map, element))
elif type(element) == str:
# substitute band number
args.append(band_map[element])
else:
# just append the number
args.append(element)
return op(args)
Because the prefix-notation is not commonly used to define mathematical formula, a function is defined that converts prefix a formula from above to infix notation. This should help to avoid errors when transcribing the index formulas, which are usually given in common infix notation:
def prefix_to_infix_str(formula):
'''
Returns a human-readable string of the above data-based notation. Useful
for debugging.
'''
result = ['(']
# operation
op = formula[0]
if op == add:
sym = ' + '
elif op == sub:
sym = ' - '
elif op == div:
sym = ' / '
elif op == mul:
sym = ' * '
operands = formula[1:]
for idx, operand in enumerate(operands, start=1):
if type(operand) == tuple:
result.append(prefix_to_infix_str(operand))
else:
result.append(str(operand))
if idx < len(operands):
result.append(sym)
result.append(')')
return ''.join(result)
#### Test Cases¶
formula = (add, *range(5), (mul, *range(1, 4))) # == (add, 0, 1, 2, 3, 4, (mul, 1, 2, 3))
prefix_to_infix_str(formula)
'(0 + 1 + 2 + 3 + 4 + (1 * 2 * 3))'
evaluate_formula({}, formula)
16
prefix_to_infix_str(indices['nbr'])
'((B08 - B12) / (B08 + B12))'
## Extraction of Relevant Band File Paths¶
Subsections from here on below contain the actual calculations. They start with the list of bands are referenced by the index formula given by index_to_calculate:
bands = get_bands(indices[index_to_calculate])
bands = list(bands)
bands
['B03', 'B08']
## Resampling¶
Some bands are not available in all resolutions - the band B08 for example is available only at a resolution of 10m and the band B12 only up to 20m.
The lower-resolution bands are upsampled to the highest resolution band:
# sorting the band path alphabetically sorts the bands first by band number,
# then by resolution
from sentinel_helpers import scihub_band_paths
band_paths = sorted(scihub_band_paths(product_path, bands))
band_paths[:3]
[PosixPath('zip+file:/home/jovyan/sources/resources/forest_fires/S2B_MSIL2A_20190701T102029_N0212_R065_T32UPE_20190701T134657.zip!/S2B_MSIL2A_20190701T102029_N0212_R065_T32UPE_20190701T134657.SAFE/GRANULE/L2A_T32UPE_A012103_20190701T102032/IMG_DATA/R10m/T32UPE_20190701T102029_B03_10m.jp2'),
PosixPath('zip+file:/home/jovyan/sources/resources/forest_fires/S2B_MSIL2A_20190701T102029_N0212_R065_T32UPE_20190701T134657.zip!/S2B_MSIL2A_20190701T102029_N0212_R065_T32UPE_20190701T134657.SAFE/GRANULE/L2A_T32UPE_A012103_20190701T102032/IMG_DATA/R10m/T32UPE_20190701T102029_B08_10m.jp2'),
PosixPath('zip+file:/home/jovyan/sources/resources/forest_fires/S2B_MSIL2A_20190701T102029_N0212_R065_T32UPE_20190701T134657.zip!/S2B_MSIL2A_20190701T102029_N0212_R065_T32UPE_20190701T134657.SAFE/GRANULE/L2A_T32UPE_A012103_20190701T102032/IMG_DATA/R20m/T32UPE_20190701T102029_B03_20m.jp2')]
highest_resolution_band_paths = []
# covered_bands ensures that only the highest resolution band is kept
covered_bands = set()
for band in band_paths:
band_num = band.name.split('_')[-2]
if band_num in covered_bands:
continue
else:
highest_resolution_band_paths.append(band)
covered_bands.add(band_num)
def resolution(band_path):
'''
Return the resolution encoded in a raster file's path.
'''
if isinstance(band_path, Path):
band_path = band_path.name
return int(band_path.split('_')[-1].split('.')[0].replace('m', ''))
# using the function above, we parse the highest resolution out of the first band path
target_resolution = sorted(resolution(band) for band in highest_resolution_band_paths)[0]
## Raster Cloud Mask Generation¶
Spectral indices can get distorted by highly reflective clouds. To avoid this the products include cloud masks, which contain information about the cloud positions in a product in order to discard them.
To construct a cloud mask, it is essential to know the transformation from the coordinates given by the raster’s coordinate reference system to the pixel coordinates of the highest resolution raster.
These are encoded as metadata in the raster file:
from sentinel_helpers import scihub_cloud_mask
import matplotlib.pyplot as plt
# pixels with clouds are True, pixels without are False
raster_cloud_mask, _ = scihub_cloud_mask(product_path)
plt.imshow(raster_cloud_mask[0])
<matplotlib.image.AxesImage at 0x7f240ea481c0>
## Index Calculation¶
import numpy as np
import numpy.ma as ma
import rasterio as r
from rasterio.enums import Resampling
import rasterio.plot as rplt
from sentinel_helpers import RasterReaderList, scihub_cloud_mask
from tqdm import tqdm
from tempfile import NamedTemporaryFile
out_dir = Path('resources/spectral_indices/')
out_dir.mkdir(exist_ok=True, parents=True)
%%time
with RasterReaderList(highest_resolution_band_paths) as readers:
# build the band_map as described above and scale up where needed
band_map = {}
for reader in tqdm(readers, desc='Resampling datasets'):
band_num = reader.name.split('_')[-2]
data_resolution = resolution(reader.name)
scale_factor = int(data_resolution / target_resolution)
out_shape = (
int(reader.height * scale_factor),
int(reader.width * scale_factor)
)
band_map[band_num] = (np.clip(
# we read only the first band to obtain a two-dimensional ndarray
reader.read(1, out_shape=out_shape, resampling=Resampling.bilinear, masked=True),
0, 10_000) / 10_000).astype('float32')
if scale_factor == 1:
# this is the target resolution which defines the shape of the
# raster file the data is written to
out_name = Path(reader.name).name.replace(band_num, index_to_calculate.upper())
out_name = out_name.replace('.jp2', '.tif')
out_path = out_dir / out_name
out_meta = reader.meta.copy()
# ignore numpy division errors (i.e. divide by 0) in this context;
# divide by zero results in nan. clouds are masked using the
# raster_cloud_mask created above
with np.errstate(divide='ignore', invalid='ignore'):
index = evaluate_formula(band_map, indices[index_to_calculate])
# we need to invert the cloud mask (~) because we want to hide those pixels that are cloudy
index.mask = index.mask | raster_cloud_mask
out_meta.update({
'count': 1,
'driver': 'COG',
'dtype': 'float32'
})
with r.open(out_path, 'w+', **out_meta) as dst:
dst.write(index.data, 1)
# note that the mask has to be inverted because "False" means masked
# when written, but unmasked for a numpy.ma.MaskedArray
dst.write_mask(~index.mask)
print(f'Wrote result to {out_path}')
Resampling datasets: 100%|██████████| 2/2 [00:32<00:00, 16.22s/it]
Wrote result to resources/spectral_indices/T32UPE_20190701T102029_NDWI_10m.tif
CPU times: user 1min 32s, sys: 19.8 s, total: 1min 52s
Wall time: 1min 4s
### Plot of Spectral Index¶
plt.figure(figsize=(6,6))
plt.imshow(index.data)
<matplotlib.image.AxesImage at 0x7f240d1265b0>
### Plot of Mask¶
White values are visible, black values are masked out.
plt.figure(figsize=(6,6))
plt.imshow(index.mask, cmap='Greys')
<matplotlib.image.AxesImage at 0x7f240c8837c0>
1
See Download Process for details
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2021-05-07 13:49:11
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http://desperatehomeschoolers.com/pages/273302-fender-fct-2-tuner
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What Started The Civil War, Floor Tile Calculator With Pattern, Dow Jones & Company, Serif Photoplus X8, Lakeland College Admission Requirements, Pepsi Logo New, How To Make Lime From Shells, Tissue Culture Teak Plant Growth, The Broad Museum Architecture, … Continue reading →" /> What Started The Civil War, Floor Tile Calculator With Pattern, Dow Jones & Company, Serif Photoplus X8, Lakeland College Admission Requirements, Pepsi Logo New, How To Make Lime From Shells, Tissue Culture Teak Plant Growth, The Broad Museum Architecture, … Continue reading →" />
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Find the square root for 40 using long division method. Given, Number = 40. Approach: Long division is a very common method to find the square root of a number. Solution. Square Roots. Is it possible to calculate? Join now. If the number of digits in it is odd, then the left-most single digit too will have a bar.Thus we have, 7 29.So 1st bar is on 29 and 2nd bar is on 7. Each pair and the remaining digit (if any) is called a period. How to extract a square root without a calculator, using the method most like long division : Group the digits by 2 with commas, starting on the right : 1,82,25. 5 years ago. ... For this particular assignment, I have to use the long division method. Carry down 96 down. This is the lost art of how they calculated the square root of 2304 by hand before modern technology was invented. Not the long division method, but another method I like that does not require a calculator. Squares and Square Roots. Actually we follow the same method as before and it is only when we do the remainder check we will have some additional work. Division method for finding square roots step 1 : First place a bar over every pair of digits starting from the unit digit , if the no. Sum of all three digit numbers divisible by 7 Solution. Questions in other subjects: English, 19.02.2020 05:10. Maths. In this video we will learn long division method step by step to find the square root of number. If you want to know the square root of 10 value approximately (exact value difficult to find), we must use the long division method definitely. To find the square root of five or six digit numbers we will expand on the method we have already seen to find the square root of three or four digit numbers. Find the Square root Shortcut Trick and Easy Way. Show Answer. Sum of all three digit numbers divisible by 6. As the number 10 is not a perfect square, so we cannot get root 10 value easily. Write the decimal number and make pairs of integer and fractional parts separately. Lv 7. 2 Answers. Find the square root of 5 2 9 using long division method. Math, 19.02.2020 05:10. how or why the method long division for finding square root of a number works. Concept Notes & Videos 249. B. Click hereto get an answer to your question ️ Find the square root of 42.25 using division method. 1. What was their driving speed on the way back? In this section we will discuss square root by long division method. Ask your question. Take this number as the divisor and also as the quotient. Ans . From left hand side for every two digits keep the bar as shown in fig. Put this under a root symbol. Correct answer to the question: Find the square root of 0.813604 by long division method - eanswers.in Let's understand why the square root by division method (digit by digit method) works. Show Answer. Log in. Answer. Question Bank Solutions 4748. Click hereto get an answer to your question ️ Find the square root of 0.09 using long division method. Square root times square root; What is the square root (sqrt) of 3? Click hereto get an answer to your question ️ Find the square root of 529 using long division method. We know, square root of 4, or 9 or 16 and we can do it instantly but the square root of 5! Show Answer. Step 1: Find the largest square smaller than 40, that's 36. Answers. So, 04 and 23 are two pairs. Find the largest perfect square of the first group -- in this case 1. Sum of all three digit numbers divisible by 7 . 13225 square root by long division method? Square Root of 5 – Long Division, Average & Equation Method. Find the greatest 3 digit and 4 digit perfect square. Translating the word problems in to algebraic expressions. L.C.M method to solve time and work problems. Ans . Group together the digits in groups of two, starting from the (virtual) decimal point: $3,61$.The first group, $3$, is larger or equal to $1^2$ and smaller than $2^2$.This means our first digit is $1$.. We subtract $1$ from $3$, which gives us $2$.Multiply by 100 and add the next group; this gives us … On their trip to Washington, DC, Jen and her parents drove 3 hours at a speed of 60 mph and then 3 hours at a speed of 40 mph. of digits are odd then the left most single digit will also have a bar Square Root of 5! Using long division find the square root of 39204 2 See answers Dharmendr Dharmendr Brainly User Brainly User √39204=198 Hope this is helpful New questions in Math. Advertisement . Concept Notes & Videos 270. Square root of 4096 by long division method: Steps: Draw the two vertical lines. How to find the square root of 676 by long division method Here we will show you how to calculate the square root of 676 using the long division method. Syllabus . Remainder when 17 power 23 is divided by 16. $$\sqrt {53824 } \ =?$$ (A) 202 (B) 232 (C) 242 (D) 332. EASY. square root of 72* square root of 338 . The square root of 64009 is : (A) 253 (B) 347 (C) 363 (D) 803. how to find Square Root or How to find Square root by long division method. Relevance. Answer Save. Square Root … Subtract 36 from 40 you will get the remainder 4. Find an answer to your question The square root of following numbers long division method 784 1. (i) 2304 Thus, Square root of 2304 = 48 Let’s look at individual steps as well Individual Steps are explained Step 1: Write the number We make pairs from right. Find the Square Root the Following by Long Division Method: 363609 Concept: Finding Square Root by Division Method. In between write the number 4096. Sum of all three digit numbers divisible by 8. To Find, Square Root of √40 using Long Division Method . A. Long division you normally know what to divide by ie 13225 / 4. Ask Question Asked 10 months ago. Put them together and you get 115. Square root of 5! Ask your question. Q.4. Syllabus. The digit in the unit’s place in the square root of 15876 is : (A) 2 (B) 4 (C) 6 (D) 8. Our apps. Finding square root using long division. ANDY. 40. Examples: Input: N = 484 Output: 22 22 2 = 484. Calculation of Square Root by Division Method. Find the square root of the following numbers using division method: 651.7809 CBSE CBSE Class 8. CBSE CBSE Class 8. Know and learn the method or the process from which you can find the approximate value of the square root of 10. Remainder when 2 power 256 is divided by 17. Steps involved in square root by long- division method. Input: N = 144 Output: 12 12 2 = 144 Recommended: Please try your approach on first, before moving on to the solution. Let's understand why the square root by division method (digit by digit method) works. Active 10 months ago. How to find the square root of 256 by long division method Here we will show you how to calculate the square root of 256 using the long division method. Remainder when 17 power 23 is divided by 16. Translating the word problems in to algebraic expressions. Q.1. Finding square root using long division. Answered The square root of following numbers long division method 784 2 See answers shashankshekhar3028 shashankshekhar3028 … Solution: Explanation: In the above example the number for which we have to calculate square root is 40. Please guide me. Question Bank Solutions 4910. Log in. This is the lost art of how they calculated the square root of 676 by hand before modern technology was invented. Following steps explain finding the square root of the decimal number 29.16 using a long division method: Step 1. How to find the square root of 2304 by long division method Here we will show you how to calculate the square root of 2304 using the long division method. Chemistry, … Answers. Step 1: Place a bar over every pair of digits starting from the unit digit. C. Solution. Driving back, they spen … t the same time. Divide the number by 2. Advertisement. Find the square root of the number 29.16. Find the Square Root the Following by Long Division Method: 390625 Concept: Square Roots - Finding Square Root by Division Method. Textbook Solutions 5346. Step II: Think of the largest number whose square is equal to or just less than the first period. Hello. Now take first two digits i.e. Ex 6.4, 1 Find the square root of each of the following numbers by Division method. Remainder when 2 power 256 is divided by 17. Many times, we surprised and shocked as well. Square Root of 5 – Long Division, Average & Equation Method. Step 2: Now, we find that number whose square is less than or equal to 23. Find the least 4 digit perfect square number. Put the square root of this on top of the root … This is the lost art of how they calculated the square root of 256 by hand before modern technology was invented. L.C.M method to solve time and work problems. Looking at it I would say that 11 x 11 = 132 and 5 x 5 = 25. Average that answer you get, with the number you divided with (2 is that number, in this first step). LEARNING APP; ANSWR; CODR; XPLOR; SCHOOL OS; 8th. Textbook Solutions 5345. If you're seeing this message, it means we're having trouble loading external resources on our website. Given an integer X which is a perfect square, the task is to find the square root of it by using long division method. Sum of all three digit numbers divisible by 6. If not you can always use newton's method for finding a square root which is much simpler then what you have above. Find the square root of 529... maths. Ans . shubhramahajan1622 shubhramahajan1622 20.05.2020 Math Secondary School +5 pts. Check that below 40 is there any perfect square number or not. Is it difficult? Steps of Long Division Method for Finding Square Roots: Step I: Group the digits in pairs, starting with the digit in the units place. Here we doing this using long division method. Solution Q.2. We can take 6 × 6 = 36 . Join now. Q.3. Viewed 179 times 1 $\begingroup$ I was wondering how this method developed and also how it works to give the square root of a number upto a large number of decimal digits .
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2021-01-16 18:04:10
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https://www.scienceopen.com/document?vid=5fdcd949-7e7e-42a2-be24-618fd7246147
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• Record: found
• Abstract: found
DNA nucleosides and their radical anions: molecular structures and electron affinities.
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There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
The deoxyribonucleosides have been studied to determine the properties of combinations of 2-deoxyribose with each of the isolated DNA bases for both neutral and anionic species. We have used a carefully calibrated theoretical method [Chem. Rev. 2002, 102, 231], employing the B3LYP hybrid Hartree-Fock/DFT functional with the DZP++ basis set. Predictions are made of the geometric parameters, adiabatic electron affinities, charge distributions based on natural population analysis, and decomposition enthalpy for the neutral and anionic forms of the four 2'-deoxyribonucleosides in DNA: 2'-deoxyriboadenosine (dA), 2'-deoxyribocytidine (dC), 2'-deoxyriboguanosine (dG), and 2'-deoxyribothymidine (dT). Geometric changes in the anions show that the glycosidic bond exhibits little change with excess charge for the guanosine but significant shortening for the adenosine and for the pyrimidines. The zero-point corrected adiabatic electron affinities in eV for each of the 2'-deoxyribonucleosides are as follows: 0.06, dA; 0.09, dG; 0.33, dC; and 0.44, dT. These values are uniformly greater than those of the corresponding isolated bases (-0.28, A; -0.07, G; 0.03, C; 0.20, T) and the isolated 2-deoxyribose (-0.38) at the same level of theory. The vertical detachment energies of dT and dC are substantial, 0.72 and 0.94 eV, and these anions should be observable. A high VDE, 0.91 eV, is also found for dA but its anion is unlikely to be stable due to the small AEA of 0.06 eV. The high VDE reflects the fact that the molecular structures of the anions and the corresponding neutral species are quite different. Valence character is displayed for the SOMOs of dA, dC, and dT, while some component of diffuse character is visible in the SOMO of dG. Further analysis of electronic changes upon electron attachment include an examination of the NPA charges, which show that in the neutral 2'-deoxyribonucleosides the sum of NPA charges for every base is the same, -0.28 with the sum of 2-deoxyribose charges being positive, +0.28. In the anions, the trend in charge division varies based on the nature of the excess electron in the anions. Thermodynamically, the overall enthalpy change for the reaction of water with the neutral nucleosides to give bases and ribose is approximately zero. The analogous decomposition is exothermic by 8 to 11 kcal mol-1 for the anions, indicating possible challenges for anionic gas-phase nucleoside exploration in the presence of water.
Author and article information
Journal
10.1021/ja030487m
15053630
Chemistry
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2019-04-21 06:44:25
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https://www.ademcetinkaya.com/2023/01/ex1-exopharm-limited.html
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Outlook: EXOPHARM LIMITED is assigned short-term Ba1 & long-term Ba1 estimated rating.
Dominant Strategy : Wait until speculative trend diminishes
Time series to forecast n: 20 Jan 2023 for (n+4 weeks)
Methodology : Ensemble Learning (ML)
## Abstract
EXOPHARM LIMITED prediction model is evaluated with Ensemble Learning (ML) and ElasticNet Regression1,2,3,4 and it is concluded that the EX1 stock is predictable in the short/long term. According to price forecasts for (n+4 weeks) period, the dominant strategy among neural network is: Wait until speculative trend diminishes
## Key Points
1. What statistical methods are used to analyze data?
2. Trust metric by Neural Network
3. What are buy sell or hold recommendations?
## EX1 Target Price Prediction Modeling Methodology
We consider EXOPHARM LIMITED Decision Process with Ensemble Learning (ML) where A is the set of discrete actions of EX1 stock holders, F is the set of discrete states, P : S × F × S → R is the transition probability distribution, R : S × F → R is the reaction function, and γ ∈ [0, 1] is a move factor for expectation.1,2,3,4
F(ElasticNet Regression)5,6,7= $\begin{array}{cccc}{p}_{a1}& {p}_{a2}& \dots & {p}_{1n}\\ & ⋮\\ {p}_{j1}& {p}_{j2}& \dots & {p}_{jn}\\ & ⋮\\ {p}_{k1}& {p}_{k2}& \dots & {p}_{kn}\\ & ⋮\\ {p}_{n1}& {p}_{n2}& \dots & {p}_{nn}\end{array}$ X R(Ensemble Learning (ML)) X S(n):→ (n+4 weeks) $\begin{array}{l}\int {r}^{s}\mathrm{rs}\end{array}$
n:Time series to forecast
p:Price signals of EX1 stock
j:Nash equilibria (Neural Network)
k:Dominated move
a:Best response for target price
For further technical information as per how our model work we invite you to visit the article below:
How do AC Investment Research machine learning (predictive) algorithms actually work?
## EX1 Stock Forecast (Buy or Sell) for (n+4 weeks)
Sample Set: Neural Network
Stock/Index: EX1 EXOPHARM LIMITED
Time series to forecast n: 20 Jan 2023 for (n+4 weeks)
According to price forecasts for (n+4 weeks) period, the dominant strategy among neural network is: Wait until speculative trend diminishes
X axis: *Likelihood% (The higher the percentage value, the more likely the event will occur.)
Y axis: *Potential Impact% (The higher the percentage value, the more likely the price will deviate.)
Z axis (Grey to Black): *Technical Analysis%
## IFRS Reconciliation Adjustments for EXOPHARM LIMITED
1. An equity method investment cannot be a hedged item in a fair value hedge. This is because the equity method recognises in profit or loss the investor's share of the investee's profit or loss, instead of changes in the investment's fair value. For a similar reason, an investment in a consolidated subsidiary cannot be a hedged item in a fair value hedge. This is because consolidation recognises in profit or loss the subsidiary's profit or loss, instead of changes in the investment's fair value. A hedge of a net investment in a foreign operation is different because it is a hedge of the foreign currency exposure, not a fair value hedge of the change in the value of the investment.
2. If an entity previously accounted at cost (in accordance with IAS 39), for an investment in an equity instrument that does not have a quoted price in an active market for an identical instrument (ie a Level 1 input) (or for a derivative asset that is linked to and must be settled by delivery of such an equity instrument) it shall measure that instrument at fair value at the date of initial application. Any difference between the previous carrying amount and the fair value shall be recognised in the opening retained earnings (or other component of equity, as appropriate) of the reporting period that includes the date of initial application.
3. There is a rebuttable presumption that unless inflation risk is contractually specified, it is not separately identifiable and reliably measurable and hence cannot be designated as a risk component of a financial instrument. However, in limited cases, it is possible to identify a risk component for inflation risk that is separately identifiable and reliably measurable because of the particular circumstances of the inflation environment and the relevant debt market
4. Such designation may be used whether paragraph 4.3.3 requires the embedded derivatives to be separated from the host contract or prohibits such separation. However, paragraph 4.3.5 would not justify designating the hybrid contract as at fair value through profit or loss in the cases set out in paragraph 4.3.5(a) and (b) because doing so would not reduce complexity or increase reliability.
*International Financial Reporting Standards (IFRS) adjustment process involves reviewing the company's financial statements and identifying any differences between the company's current accounting practices and the requirements of the IFRS. If there are any such differences, neural network makes adjustments to financial statements to bring them into compliance with the IFRS.
## Conclusions
EXOPHARM LIMITED is assigned short-term Ba1 & long-term Ba1 estimated rating. EXOPHARM LIMITED prediction model is evaluated with Ensemble Learning (ML) and ElasticNet Regression1,2,3,4 and it is concluded that the EX1 stock is predictable in the short/long term. According to price forecasts for (n+4 weeks) period, the dominant strategy among neural network is: Wait until speculative trend diminishes
### EX1 EXOPHARM LIMITED Financial Analysis*
Rating Short-Term Long-Term Senior
Outlook*Ba1Ba1
Income StatementBa2Baa2
Balance SheetBaa2Baa2
Leverage RatiosBaa2B2
Cash FlowCaa2Caa2
Rates of Return and ProfitabilityBaa2B3
*Financial analysis is the process of evaluating a company's financial performance and position by neural network. It involves reviewing the company's financial statements, including the balance sheet, income statement, and cash flow statement, as well as other financial reports and documents.
How does neural network examine financial reports and understand financial state of the company?
### Prediction Confidence Score
Trust metric by Neural Network: 92 out of 100 with 639 signals.
## References
1. uyer, S. Whiteson, B. Bakker, and N. A. Vlassis. Multiagent reinforcement learning for urban traffic control using coordination graphs. In Machine Learning and Knowledge Discovery in Databases, European Conference, ECML/PKDD 2008, Antwerp, Belgium, September 15-19, 2008, Proceedings, Part I, pages 656–671, 2008.
2. Chow, G. C. (1960), "Tests of equality between sets of coefficients in two linear regressions," Econometrica, 28, 591–605.
3. Hartford J, Lewis G, Taddy M. 2016. Counterfactual prediction with deep instrumental variables networks. arXiv:1612.09596 [stat.AP]
4. D. Bertsekas and J. Tsitsiklis. Neuro-dynamic programming. Athena Scientific, 1996.
5. Bell RM, Koren Y. 2007. Lessons from the Netflix prize challenge. ACM SIGKDD Explor. Newsl. 9:75–79
6. Breiman L. 1996. Bagging predictors. Mach. Learn. 24:123–40
7. A. Tamar, D. Di Castro, and S. Mannor. Policy gradients with variance related risk criteria. In Proceedings of the Twenty-Ninth International Conference on Machine Learning, pages 387–396, 2012.
Frequently Asked QuestionsQ: What is the prediction methodology for EX1 stock?
A: EX1 stock prediction methodology: We evaluate the prediction models Ensemble Learning (ML) and ElasticNet Regression
Q: Is EX1 stock a buy or sell?
A: The dominant strategy among neural network is to Wait until speculative trend diminishes EX1 Stock.
Q: Is EXOPHARM LIMITED stock a good investment?
A: The consensus rating for EXOPHARM LIMITED is Wait until speculative trend diminishes and is assigned short-term Ba1 & long-term Ba1 estimated rating.
Q: What is the consensus rating of EX1 stock?
A: The consensus rating for EX1 is Wait until speculative trend diminishes.
Q: What is the prediction period for EX1 stock?
A: The prediction period for EX1 is (n+4 weeks)
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2023-03-27 10:57:37
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https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Supplemental_Modules_(Biological_Chemistry)/Enzymes/Enzymatic_Kinetics/Turnover_Number
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# Turnover Number
In enzyme kinetics, we are interested to know how many maximum molecules of substrate can be converted into product per catalytic site of a given concentration of enzyme per unit time.
$k_{cat} =\dfrac{ V_{max}}{E_t}$
with
• The units of Turn over number (kcat) are $$k_{cat}$$ = (moles of product/sec)/ (moles of enzyme) or sec-1.
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2022-10-02 13:31:48
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http://mkweb.bcgsc.ca/pi/piday2018/methods.mhtml
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Here we are now at the middle of the fourth large part of this talk.get nowheremore quotes
# pi: fun
In Silico Flurries: Computing a world of snow. Scientific American. 23 December 2017
# visualization + design
The 2018 Pi Day art celebrates the 30th anniversary of $\pi$ day and connects friends stitching road maps from around the world. Pack a sandwich and let's go!
# $\pi$ Day 2018 Art Posters - Stitched city road maps from around the world
2018 $\pi$ day shrinks the world and celebrates road trips by stitching streets from around the world together. In this version, we look at the boonies, burbs and boutique of $\pi$ by drawing progressively denser patches of streets. Let's go places.
2017 $\pi$ day
2016 $\pi$ approximation day
2016 $\pi$ day
2015 $\pi$ day
2014 $\pi$ approx day
2014 $\pi$ day
2013 $\pi$ day
Circular $\pi$ art
On March 14th celebrate $\pi$ Day. Hug $\pi$—find a way to do it.
For those who favour $\tau=2\pi$ will have to postpone celebrations until July 26th. That's what you get for thinking that $\pi$ is wrong.
If you're not into details, you may opt to party on July 22nd, which is $\pi$ approximation day ($\pi$ ≈ 22/7). It's 20% more accurate that the official $\pi$ day!
Finally, if you believe that $\pi = 3$, you should read why $\pi$ is not equal to 3.
All art posters are available for purchase.
I take custom requests.
And if you've got to sleep a moment on the road
I will steer for you
And if you want to work the street alone
I'll disappear for you
This year's is the 30th anniversary of $\pi$ day. The theme of the art is bridging the world and making friends. So myself I again team up with my long-time friend and collaborator Jake Lever. I worled with Jake on the snowflake catalogue, where we build a world of flakes.
And so, this year we also build a world. We start with all the roads in the world and stitch them together in brand new ways. And if you walk more than 1 km in this world, you'll likely to be transported somewhere completely different.
This year's $\pi$ day song is Trance Groove: Paris. Why? Because it's worth to go to new places—real or imagined.
The input data set to the art are all the roads in the world, as obtained from Open Street Map.
Road segments between intersections are represented by polylines and ends at intersections are snapped together to coincide with a resolution of 5–10 meters.
There are 108,366,429 polylines and together they span about 39,930,000 km.
## extracting cities
We took 44 cities and sampled a square patch of 0.6 × 0.6 degrees of roads from the data set centered on the longitude and latitude coordinates below. This roughly corresponds to a square of 65 km × 65 km.
These center coordinates might be slightly different from the canonical ones associated with a city—I used Google Maps to center the coordinates on what I felt was a useful center for sampling streets. Below are these coordinates along with the number of polylines extracted.
CITY LATITUDE LONGITUDE POLYLINES
--------------- ------------ ------------- ---------
amsterdam 52.38179720 4.90840330 98,965
bangkok 13.72635950 100.53609560 154,348
barcelona 41.38759720 2.17333560 86,575
beijing 39.90487690 116.39331750 49,867
berlin 52.51864170 13.40732310 64,336
buenos_aires -34.61566250 -58.50333750 267,432
cairo 30.05371250 31.23528970 108,524
copenhagen 55.67346250 12.58781160 45,025
doha 25.28233490 51.53479620 50,458
dublin 53.34316360 -6.24433520 44,109
edinburgh 55.94884870 -3.18828100 34,211
hong_kong 22.31338230 114.16994610 36,329
istanbul 41.03592820 28.98158110 190,938
jakarta -6.21858830 106.85252890 253,211
johannesburg -26.20653880 28.05113830 128,840
lisbon 38.73064000 -9.13667460 98,118
london 51.50838960 -0.08585320 169,164
los_angeles 34.04362360 -118.24505510 193,899
marrakesh 31.63192610 -7.98895890 17,442
melbourne -37.88286720 145.11800540 140,817
mexico_city 19.39741470 -99.15827060 273,477
moscow 55.75202630 37.61531070 40,043
mumbai 19.18775070 72.97777590 65,316
nairobi -1.28718700 36.83157870 31,317
new_delhi 28.61245350 77.21369970 262,503
new_york 40.72187290 -73.92426750 199,652
nice 43.70006260 7.26974590 25,564
osaka 34.66944300 135.49965600 376,652
paris 48.85837360 2.29229260 175,028
prague 50.08022370 14.43002100 58,659
rome 41.89659480 12.49983650 81,370
san_francisco 37.77526950 -122.40966350 82,462
sao_paulo -23.57343700 -46.63341590 267,742
seoul 37.54869140 126.99479350 169,593
shanghai 31.22590500 121.47386710 50,036
st_petersburg 59.93029690 30.33955910 31,186
stockholm 59.32318770 18.07408060 48,321
sydney -33.86772020 151.20734660 76,820
tokyo 35.69220740 139.75613010 694,893
toronto 43.66328030 -79.38932030 73,173
vancouver 49.25782630 -123.19394300 34,081
vienna 48.20740250 16.37336040 53,669
warsaw 52.23101840 21.01639680 54,870
Each city's road coordinates were then transformed using the equirectangular projection to make the distance between longitude meridians constant with latitude. This was done by $$\phi' \leftarrow \phi - \text{avg}(\phi)$$ $$\lambda' \leftarrow (\lambda - avg(\lambda)) \text{cos} (avg(\phi))$$
where $\phi$ is the latitude and $\lambda$ is the longitude. The average is taken over the patch of roads extracted for the city. For all steps below these transformed coordinates were used.
## copenhagen
Let's look at one city—Copenhagen—to get a feel for the data set.
The roads in and around Copenhagen. (zoom)
In the zoom crop below, you can see the intersections (dots) and the individual polylines that connect the intersections.
Downtown Copenhagen. (zoom)
Zooming in even more you can see the Christiansborg Slot, one of the Danish Palaces and the seat of the Danish Parliament (corresponding Google Map view).
In and around Christiansborg Slot (red dot) in downtown Copenhagen. (zoom)
## creating city strips
City strips were created by sampling patches of 0.015 × 0.015 degrees (after transformation). This corresponds roughly to 1.7 km.
For each position in the strip, patches were sampled in order of the digits of $\pi$ only if the number of polylines in the was $40d \le N < 40(d+1)-1$ where $d$ is the digit of $\pi$. Patches for $d=9$ only need to have $360 \le N$ polylines.
For example, the first patch is assigned to $d=3$ and it must have $120 \le N < 159$ polylines. The second patch is sampled so that its density is $40 \le N < 79$ because it is associated with the next digit, $d=1$.
Further selection on acceptable patches is performed so that the streets line up with the previous patch. Minor local adjustments and stitching are performed to make the join appear seamless.
Below is an example of a set of city strips for Amsterdam, Bangkok, Beijing, Berlin, Copenhagen, Edinburgh, Hong Kong, Johannesburg, Marrakesh and Melbourne.
On the road with 10 digits of $\pi$. City strips for Moscow, Mumbai, Nairobi, New Delhi, Nice, Prague, Rome, Stockholm, Vancouver and Warsaw. (BUY ARTWORK)
Below I zoom in on a portion of the city strips above to show the result of the stitching—individual street patches are outlined in blue squares.
Close-up of stitched streets in a city strip.
It's interesting to see that some patches (e.g. 4th one on the bottom strip, which is Copenhagen) don't necessarily have roads that across the patch horizontally.
## creating world patches
World patches are a two-dimension version of city strips but they use more than one city.
Patches are sampled from cities based on the order of the digits of $\pi$, as arranged on a 6 × 6 grid. For example, the first row of patches corresponds to 314159 and the second 265358. Each digit is assigned to a city from which the corresponding patch is sampled.
As for city strips, patches are selected only if they align with previous patches. This is now trickier to do in two-dimensions because we must match a selected patch with up to two other patches already placed.
Unlike for city strips, there is no selection made for street density.
Below is a world patch using the following digit-to-city assignment: 0:Amsterdam, 1:Doha, 2:Marrakesh, 3:Mumbai, 4:Nairobi, 5:Rome, 6:San Francisco, 7:Seoul, 8:Shanghai and 9:Vancouver.
On the road with 36 digits of $\pi$. A world patch using Amsterdam, Doha, Marrakesh, Mumbai, Nairobi, Rome, San Francisco, Seoul, Shanghai and Vancouver (BUY ARTWORK)
Below I zoom in on patches in the center of the image and show the cities from which the patches were sampled.
Close-up of stitched streets in a world patch.
VIEW ALL
# Find and snap to colors in an image
Sat 29-12-2018
One of my color tools, the colorsnap application snaps colors in an image to a set of reference colors and reports their proportion.
Below is Times Square rendered using the colors of the MTA subway lines.
Colors used by the New York MTA subway lines.
Times Square in New York City.
Times Square in New York City rendered using colors of the MTA subway lines.
Granger rainbow snapped to subway lines colors from four cities. (zoom)
# Take your medicine ... now
Wed 19-12-2018
Drugs could be more effective if taken when the genetic proteins they target are most active.
Design tip: rediscover CMYK primaries.
More of my American Scientific Graphic Science designs
Ruben et al. A database of tissue-specific rhythmically expressed human genes has potential applications in circadian medicine Science Translational Medicine 10 Issue 458, eaat8806.
# Predicting with confidence and tolerance
Wed 07-11-2018
I abhor averages. I like the individual case. —J.D. Brandeis.
We focus on the important distinction between confidence intervals, typically used to express uncertainty of a sampling statistic such as the mean and, prediction and tolerance intervals, used to make statements about the next value to be drawn from the population.
Confidence intervals provide coverage of a single point—the population mean—with the assurance that the probability of non-coverage is some acceptable value (e.g. 0.05). On the other hand, prediction and tolerance intervals both give information about typical values from the population and the percentage of the population expected to be in the interval. For example, a tolerance interval can be configured to tell us what fraction of sampled values (e.g. 95%) will fall into an interval some fraction of the time (e.g. 95%).
Nature Methods Points of Significance column: Predicting with confidence and tolerance. (read)
Altman, N. & Krzywinski, M. (2018) Points of significance: Predicting with confidence and tolerance Nature Methods 15:843–844.
Krzywinski, M. & Altman, N. (2013) Points of significance: Importance of being uncertain. Nature Methods 10:809–810.
# 4-day Circos course
Wed 31-10-2018
A 4-day introductory course on genome data parsing and visualization using Circos. Prepared for the Bioinformatics and Genome Analysis course in Institut Pasteur Tunis, Tunis, Tunisia.
Composite of the kinds of images you will learn to make in this course.
# Oryza longistaminata genome cake
Mon 24-09-2018
Data visualization should be informative and, where possible, tasty.
Stefan Reuscher from Bioscience and Biotechnology Center at Nagoya University celebrates a publication with a Circos cake.
The cake shows an overview of a de-novo assembled genome of a wild rice species Oryza longistaminata.
Circos cake celebrating Reuscher et al. 2018 publication of the Oryza longistaminata genome.
# Optimal experimental design
Tue 31-07-2018
Customize the experiment for the setting instead of adjusting the setting to fit a classical design.
The presence of constraints in experiments, such as sample size restrictions, awkward blocking or disallowed treatment combinations may make using classical designs very difficult or impossible.
Optimal design is a powerful, general purpose alternative for high quality, statistically grounded designs under nonstandard conditions.
Nature Methods Points of Significance column: Optimal experimental design. (read)
We discuss two types of optimal designs (D-optimal and I-optimal) and show how it can be applied to a scenario with sample size and blocking constraints.
Smucker, B., Krzywinski, M. & Altman, N. (2018) Points of significance: Optimal experimental design Nature Methods 15:599–600.
Krzywinski, M., Altman, N. (2014) Points of significance: Two factor designs. Nature Methods 11:1187–1188.
Krzywinski, M. & Altman, N. (2014) Points of significance: Analysis of variance (ANOVA) and blocking. Nature Methods 11:699–700.
Krzywinski, M. & Altman, N. (2014) Points of significance: Designing comparative experiments. Nature Methods 11:597–598.
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2019-02-15 22:34:31
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https://ptwiddle.github.io/Graph-Theory-Notes/ch_graphs_on_surfaces.html
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# Chapter4Graphs on Surfaces
This chapter covers drawing graphs on surfaces. To motivate this topic, we will begin by thinking about videogames
We start with discussing whether or not graphs are planar, proving that $K_{3,3}$ and $K_5$ are not planar using a method we call the Planarity Algorithm for Hamiltonian graphs. We discuss the more general Kuratowski's theorem for proving any graph is planar or not. We introduce other surfaces, and how to draw graphs on them -- the sphere, Mobius band, and torus in particular. After a brief discussion of dual graphs, we prove Euler's theorem about planar graphs and explore several applications.
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2020-01-18 23:39:34
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