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More and more, the operations of our businesses, governments, and financial institutions are controlled by information that exists only inside computer memories. Anyone clever enough to modify（修改，更改）this information for his own purposes can reap（收获）substantial reward. Even worse, a number of people who have done this and been caught at it have managed to get away without punishment.
It's easy for computer crimes to go undetected if no one checks up on what the computer is doing. But even if the crime is detected, the criminal may walk away not only unpunished but with a glowing recommendation from his former employers.
Of course, we have no statistics on crimes that go undetected. But it's disturbing to note how many of the crimes we do know about were detected by accident, not by systematic inspections or other security procedures. The computer criminals who have been caught may have been the victims of uncommonly bad luck.
For example, a certain keypunch（打孔机), operator complained of having to stay overtime to punch extra cards. Investigation revealed that the extra cards she was being asked to punch were for dishonest transactions. In another case, dissatisfied employees of the thief tipped off the company that was being robbed.
Unlike other lawbreakers, who must leave the country, commit suicide, or go to jail, computer criminals sometimes escape punishment, demanding not only that they not be charged but that they be given good recommendations and perhaps other benefits. All too often, their demands have been met.
Why? Because company executives are afraid of the bad publicity that would result if the public found out that their computer had been misused. They hesitate at the thought of a criminal boasting in open court of how he juggled（欺骗）the most confidential（机密的）records right under the noses of the company's executives, accountants and security staff. And so another computer criminal departs with just the recommendations he needs to continue his crimes elsewhere.
1
It can be concluded from the passage that_____.
A.
it is still impossible to detect computer crimes today
B.
people commit computer crimes at the request of their company
C.
computer criminals escape punishment because they can't be detected
D.
computer crimes are the most serious problem in the operation of financial institutions
本题答案：
A
B
C
D
参考答案：
D
系统解析：
推断题。根据文章第二、第三段可排除选项A和C；根据全文内容，选项B明显错误；根据文章第—段，正确答案应是D。
2
It is implied in the third paragraph that_____.
A.
most computer criminals who are caught blame their bad luck
B.
the rapid increase of computer crimes is a troublesome problem
C.
most computer criminals are smart enough to cover up their crimes
D.
many more computer crimes go undetected than are discovered
本题答案：
A
B
C
D
参考答案：
D
系统解析：
推断题。第三段第三句“The computer criminals who have been caught may have been the victims of uncommonly bad luck”意思是“被抓到的罪犯都是非常罕见的运气不好的人”，即大多数罪犯都未被抓到。所以可以推断出D项正确。第三段未提到选项A、B和C。
3
Which of the following is mentioned in the passage?
A.
A strict law against computer crimes must be enforced.
B.
Companies usually hesitate to uncover computer crimes to protect their reputation.
C.
Companies will guard against computer crimes to protect their reputation.
D.
Companies need to impose restrictions on confidential information.
本题答案：
A
B
C
D
参考答案：
B
系统解析：
判断题。根据文章最后一段可排除选项A、C和D。
4
What may happen to computer criminals once they are caught?
A.
With a bad reputation they can hardly find another job.
B.
They may walk away and easily find another job.
C.
They will be denied access to confidential records.
D.
They must leave the country or go to jail.
本题答案：
A
B
C
D
参考答案：
B
系统解析：
细节题。根据第二段的最后一句话、第五段、第六段最后一句可知B项是正确答案。选项A、C和与文章意思相反。
5
The passage is mainly about _____.
A.
why computer criminals are often able to escape punishment
B.
why computer crimes are difficult to detect by systematic inspections
C.
how computer criminals manage to get good recommendations from their former employers
D.
why computer crimes can't be eliminated
本题答案：
A
B
C
D
参考答案：
A
系统解析：
主旨题。本文主要给我们举例说明利用计算机犯罪的情况并分析了这种罪犯不但可以不受惩罚， 反而可以轻而易举地得以继续犯罪的原因。第一段是主题段，提出计算机罪犯可以轻而易举地逃脱惩罚；第二至第四段说明第原因，即计算机犯罪很难被发现；第五至第六段说明第二个原因，即为了公司的声誉，公司主管即使发现了计算机罪犯也不会惩罚他们，反而还要给他们提供推荐及其他的好处。
It is a sheer（绝对的）chance that the moon，because of its size and orbit（轨道）, neatly I covers the sun during a total eclipse like a plug in a drain. For scientists，it is nothing less than heaven-sent luck. The sun is so bright that most early solar research had to be done during i eclipses. Space stations and the coronagraph（日冕仪）, a telescope that produces an artificial [eclipse，have changed that. But still, researchers from Russia, Brazil, Japan，the U.S. and other countries fanned out（扇形展开）across Asia last week for a few fleeting seconds of quality observation time useful for a range of disciplines.
Many were trying to determine the exact diameter of the sun，which remains unknown. On Borneo，Professor John Parkinson of University College London wanted an exact timing of the eclipse's duration，which，together with information about the size and distance of the moon, could determine the figure for the sun's size. Indian scientists took a different approach: they sought a precise（精确的）measurement of the shadow cast on the earth. Three Indian air force planes were deployed with cameramen and scientists to examine the shadow. Separately，a pair of MiG - 25 fighters（米格-25战斗机）were fitted with equipment to photograph the sun corona and the dust rings around it. They traveled along the path of the eclipse at 3,000 km/h，gaining several precious minutes of observation denied researchers stuck on the ground.
On earth, communications experts measured radio waves in an attempt to determine the exact change in the density of the atmosphere at different stages of the blackout. Botanists measured changes in plants as the light dimmed and temperatures dropped. Zoologists watched for unusual behavior among birds, fish and orangutans（猩猩）. In ancient times eclipses dispersed（驱散）armies in the midst of fierce battles; today they attract fresh troops carrying not swords or guns but cameras and computers.
6
The first sentence of the text means that it's rare that_____.
A.
the moon shelters the sun partially
B.
the moon blocks the sun completely
C.
the earth shadows the moon neatly
D.
the earth just covers the moon
本题答案：
A
B
C
D
参考答案：
B
系统解析：
细节题，也考查个别词汇。第一句原文用的是neatly covers，与选项B中的blocks completely意思相同，都有“完全覆盖，全部遮挡”的意思。
7
Which of the following happened during the eclipse?
A.
Professor Parkinson took pictures of the sun and its dust rings.
B.
British scientists went near to the moon's shadow and studied it.
C.
Indian fighters flew at high speed to see how long the eclipse lasted-
D.
Indian scientists measured the shadow of eclipse cast on the earth.
本题答案：
A
B
C
D
参考答案：
D
系统解析：
细节题。答案参见第二段。根据第二段第三句“Indian scientists took a different approach: they sought a precise measurement of the shadow cast on the earth.”可知，D项是正确答案。
8
The writer seems to suggest that a total eclipse is _____.
A.
quite unusual
B.
common in history
C.
less useful than an artificial one
D.
harmful to plants and animals
本题答案：
A
B
C
D
参考答案：
D
系统解析：
推断题。第一段第一句话明确提到选项A的内容，而本题使用suggest，意思是“暗含什么意思”，所以排除选项A；选项B与选项A意思相反，也不符合题意，明显不对；本章第三段提到植物学家和动物学家在日食发生时观察到了植物的变化和动物的异常行为，由此可推断出正确答案为D项。
9
From the second paragraph we learn that_____.
A.
even now we can't say for sure how large the moon is
B.
it is difficult to determine how long an eclipse will last
C.
the sun's size is still something to be estimated and decided
D.
the moon's shadow denies researchers enough time for observation
本题答案：
A
B
C
D
参考答案：
C
系统解析：
细节题。根据第二段第一句，太阳的直径还不为人知，所以选C项。
10
According to the writer, what would ancient people possibly do during an eclipse?
A.
People would rush out of their dwellings to see it.
B.
People would watch for unusual behaviors of animals.
C.
People would fight an even more fierce battle.
D.
People would be terribly scared and flee for shelter.
本题答案：
A
B
C
D
参考答案：
D
系统解析：
细节题。根据第三段最后一句“In ancient times eclipses dispersed armies in the midst of fierce battles... ”可知，古代人对日食缺乏了解，因此会产生恐惧心理：日食发生时，正在激烈战斗的士兵都会四下溃散，所以选D项。
During past ages dramatic changes have taken place inside the earth. And changes are still going on today. They show themselves in the occurrence of earthquakes, in the outbursts of volcanoes, and in the uplift of mountain ranges.
In outward appearance，the earth is a nearly spherical（球形的）ball with a radius（半径）of 6,350 kilometers. Internally the earth consists of two parts，a core and a mantle（地幔，地核与地壳之间的部分，主要由氧和硅构成，占地绿体积的80%）. The core is made of rather dense stuff. The materials at the center of the earth is at least thirteen times as heavy as ordinary water, while at the outer parts of the core the material is about ten times as heavy as ordinary water.
The mantle possesses a thin outer crust（地壳）that is exceptional（异常的）in being composed of a particularly light kind of rock. Over the continents of the world this crustal（硬壳，外壳）rock is about thirty-five kilometers thick, while over the oceans it is at most only two or three kilometers thick. Below the crustal layer comes a different, dense rock, probably of a basic silicate（硅酸盐）variety. Indeed apart from the thin outer crust，the rocks of the whole mantle are of a basic silicate variety right down to the junction（结合处）with the core, at a depth below the surface of about 2,900 kilometers. As we go inwards to greater and greater depths, the density of rocks of the earth's mantle increases. The density immediately below the outer crust is about 3.3 times that of water. We may compare this with a density of 4.0 at a depth of 500 kilometers, 4. 5 at 1,000 kilometers, about 5. 0 at 2,000 kilometers, and with about 5.6 at the surface of the core, which is at a depth of 2,900 kilometers.
The last of these values is important. We are now saying that in the part of mantle immediately outside the core, the density is about 5.6 times that of water. On the other hand immediately inside the core the density is about 9.7. This means that at the surface of the core there is not only a change from liquid on the inside to solid on the outside, but there is also a very considerable change in the density of material, from 9. 7 on the inside to 5. 6 on the outside. This change gives an important clue to the nature of the material in the core.
11
Changes inside the earth show themselves in the forms of _____.
A.
the happening of earthquakes
B.
the eruption of volcanoes
C.
the uplift of mountains
D.
all of the above
本题答案：
A
B
C
D
参考答案：
D
系统解析：
细节题。答案参见文章第一段第三句“show themselves in the occurrence of earthquake, in the outbursts of volcanoes, and in the uplift of mountain ranges”，这句话告诉我们地球内部的变化在地表上的表现包括地震、火山喷发和山脉的上升隆起，因此只能选B项，前三个选项都不全面，所以不对。
12
According to the passage, the diameter of the earth is about_____.
A.
6,350 kilometers
B.
12,700 kilometers
C.
3,450 kilometers
D.
6,900 kilometers
本题答案：
A
B
C
D
参考答案：
B
系统解析：
细节题。根据文章第二段第一句“the earth is a nearly spherical ball with a radius of 6,350 kilometers”，可知地球的半径是6350千米，直径（diameter）应该是12700千米.所以选B项。
13
The word "dense" (Line 4，Para.3) could possibly mean_____.
A.
flat
B.
sensitive
C.
thick
D.
oval
本题答案：
A
B
C
D
参考答案：
C
系统解析：
词汇根据文韋第三段第二句“over the continents of the world this crustal rock is about thirty-five kilometers thick, while over the oceans...kilometers thick”，可知接下来的这句话中 dense 修饰rock，应该与上文的thick同义，所以选C项。
14
The great change in the density of the material inside and outside the core throws light on
A.
the nature of the material in the core
B.
the pressures occurring inside the earth
C.
the shape of the earth
D.
the density of the material at the depth of 500 kilometers inside the core
本题答案：
A
B
C
D
参考答案：
A
系统解析：
细节题。根据第四段最后一句“This change gives an important clue to the nature of the material in the core”，可知地核内外的物质密度的变化正好说明了地核内物质的特性。所以选A项。
15
The passage mainly informs the reader_____.
A.
the changes inside the earth
B.
the interior of the earth
C.
the composition of the mantle
D.
the appearance of the core
本题答案：
A
B
C
D
参考答案：
B
系统解析：
主旨题。本文以地球内部的大小、结构、物质密度和地表变化等为主线展开说明，对地表变化的说明主要是为了说明其内部的变化，所以应选B项。
Imagine eating everything delicious you want with none of the fat. That would be great, wouldn't it?
New "fake fat" products appear on store shelves in the United States recently, but not everyone is happy about it. Makers of the products，which contain a compound called olestra, say food manufacturers can now eliminate fat from certain foods. Critics, however, say the new compound can rob the body of essential vitamins and nutrients（营养物）and can also cause unpleasant side effects in some people. So it's up to consumers to decide whether the new fat free products taste good enough to keep eating.
Chemists discovered olestra in the late 1960s, when they were searching for fat that could be digested by infants more easily. Instead of finding the desired fat, the researchers created a fat that can't be digested at all.
Normally, special chemicals in the intestines（肠）"grab" molecules of regular fat and break them down so they can be used by the body. A molecule of regular fat is made up of three molecules of substances called fatty acids.
The fatty acids are absorbed by the intestines and bring with them the essential vitamins A, D, E, and K. When fat molecules are present in the intestines with any of those vitamins, the vitamins attach to the molecules and are carried into the bloodstream.
Olestra, which is made from six to eight molecules of fatty acids, is too large for the intestines to absorb. It just slides through the intestines without being broken down. Manufactures say it's that ability to slide unchanged through the intestines that makes olestra so valuable as a fat substitute. It provides consumers with the taste of regular fat without any bad effects on the body. But critics say olestra can prevent vitamins A, D, E, and K from being absorbed. It can also prevent the absorption of carotenoids（类胡萝卜素）, compounds that may reduce the risk of cancer, heart disease, etc.
Manufacturers are adding vitamins A, D，E, and K as well as carotenoids to their products now. Even so, some nutritionists are still concerned that people might eat unlimited amounts of food made with the fat substitute without worrying about how many calories they are consuming.
16
We learn from the passage that olestra is a substance that _____.
A.
contains plenty of nutrients
B.
makes foods fat-free while keeping them delicious
C.
renders foods calorie-free while retaining their vitamins
D.
makes food easily digestible
本题答案：
A
B
C
D
参考答案：
B
系统解析：
推新题。olestra 去除了食品中的脂肪，保留了食物的美味。文章第二段第二句指出生产这种含有olestra的食物的人说他们已从食物中去除了脂肪；最后一句谈到消费者根据食品的味道来决定是否长期食用，换言之，消费者并没有发现这种新食品不好吃。因此选项B正确。其他选项均与文章内容不符。
17
The result of the search for an easily digestible fat turned out to be_____.
A.
just as anticipated
B.
commercially useless
C.
quite unexpected
D.
somewhat controversial
本题答案：
A
B
C
D
参考答案：
C
系统解析：
推断题。文中第二段说化学家们在60年代末想找到易于婴儿消化的一种脂肪，结果却找到了根本不能消化的olestra，因此选项C正确。选项A与文章意思相反；文章未提到选项B和选项D。
18
Olestra is different from ordinary fats in that_____.
A.
it facilitates the absorption of vitamins by the body
B.
it passes through the intestines without being absorbed
C.
it helps reduce the incidence of heart disease
D.
it prevents excessive intake of vitamins
本题答案：
A
B
C
D
参考答案：
B
系统解析：
细节题。文章第六段第一、第二句说到“Olestra, which is made from six to eight molecules of fatty acids, is too large for the intestines to absorb. It just slides through the intestines without being broken down.”。由此可确定选项B正确。选项A和C与文中意思相反。文章未提及选项D。
19
What is possible negative effect of olestra according to some critics?
A.
It may increase the risk of cancer.
B.
It may impair the digestive system.
C.
It may spoil the consumers' appetite.
D.
It may affect the overall fat intake.
本题答案：
A
B
C
D
参考答案：
A
系统解析：
推断题。文章第六段最后一句说olestra阻止了类胡萝卜素和其他一些化合物被人体吸收，而这些化合物会减少癌症和心脏病的发生，由此得出答案是A项。文中未提到选项B、C和D。
20
Why are nutritionists concerned about adding vitamins to Olestra ?
A.
People may be induced to eat more than is necessary.
B.
It may trigger a new wave of fake food production.
C.
It may lead to the over-consumption of vitamins.
D.
The function of intestines may be weakened.
本题答案：
A
B
C
D
参考答案：
A
系统解析：
推断题。根据文章最后一段最后一句“Even so, some nutritionists are still concerned that people might eat unlimited amounts of food made with the fat substitute without worrying about how many calories they are consuming.”可以推断，A项正确。其他选项文章均未提到。
The temperature of the Sun is over 5,000 degrees Fahrenheit at the surface, but it rises to perhaps more than 16 million degrees at the center. The Sun is so much hotter than the Earth that matter can exist only as a gas, except at the core. In the core of the Sun, the pressures are so great against the gases that, despite the high temperature, there may be a small solid core. However, no one really knows, since the center of the Sun can never be directly observed.
Solar astronomers do know that the Sun is divided into five layers of zones. Starting at the outside and going down into the sun，the zones are the corona（日冕）, chromosphere（色球层）,photosphere（光球层）, convection zone（对流层）, and finally the core（日核）. The first three zones are regarded as the Sun's atmosphere ends and the main body of the Sun begins.
The Sun's outermost layer begins about 10, 000 miles above the visible surface and goes outward for millions of miles. This is the only part of the Sun that can be seen during an eclipse such as the one in February 1979. At any other time, the corona can be seen only when special instruments are used on cameras and telescopes to shut out the glare of the Sun's rays.
The corona is a brilliant, pearly white, filmy light, about as bright as the full Moon. Its beautiful rays are a sensational sight during an eclipse. The corona's rays flash out in a brilliant fan that has wispy spider like rays near the Sun's north and south poles. The corona is thickest at the Sun's equator（赤道似的圈圆）.
The corona rays are made up of gases streaming outward at tremendous speeds and reaching a temperature of more than 2 million degrees Fahrenheit. The rays of gas thin out（变弱）as they reach the space around the planets. By the time the Sun's corona rays reach the Earth，they are weak and invisible.
21
Matter on the Sun can exist only in the form of gas because of the Sun's _____.
A.
size
B.
age
C.
location
D.
temperature
本题答案：
A
B
C
D
参考答案：
D
系统解析：
细节题。根据文章第一段第二句“The Sun is so much hotter than the Earth that matter can exist only as gas.”可知，D项为正确答案。
22
With what topic is the second paragraph mainly concerned?
A.
How the sun evolved.
B.
The structure of the Sun.
C.
Why scientists study the Sun.
D.
The distance of the Sun from the planets.
本题答案：
A
B
C
D
参考答案：
B
系统解析：
推断题。很明显，文章第二段说明了太阳结构分为五层。故B项为正确答案。
23
All of the following are parts of the Sun's atmosphere EXCEPT the _____.
A.
corona
B.
chromosphere
C.
photosphere
D.
core
本题答案：
A
B
C
D
参考答案：
D
系统解析：
细节题。根据文章第二段最后一句“The first three zones are regarded as the Sun's atmosphere...”可知，the first three zones 指上句话提到的 corona（日冕层），chromosphere（色球层）和 photosphere（光球层），所以D项为正确答案。
24
According to the passage, as the corona rays reach the planets, they become_____.
A.
hotter
B.
clearer
C.
thinner
D.
stronger
本题答案：
A
B
C
D
参考答案：
C
系统解析：
细节题。根据文聿第五段第二句“The rays of has thin out...”可知，C项正确。
25
The paragraph following the passage will most likely discuss_____.
A.
the remaining layers of the Sun
B.
the evolution of the Sun to its present form
C.
comparison between the Sun and the Moon
D.
what does the sun do to people
本题答案：
A
B
C
D
参考答案：
A
系统解析：
推断题。做这类题目，除了了解文章的总体结构之外，主要看最后一段作者论述的内容。文章第四段和第五段详细说明了 corona（日冕层）的情况，由此可知，作者很可能下文将按太阳由外向里的分层结构逐一说明。所以A项正确。
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