考前30天阅读理解练习四

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A

Suppose we built a robot to explore the planet Mars. We provide the robot with seeing detectors（探测器） to keep it away from danger. It is powered entirely by the sun. Should we program the robot to be equally active at all times？ No， the robot would be using up energy at a time when it was not receiving any. So we would probably program it to stop its activity at night and to wake up at dawn the next morning.

According to evolutionary（进化的） theory of sleep， evolution equipped us with a regular pattern of sleeping and waking for the same reason. The theory does not deny that sleep provides some important restorative functions. It merely says that evolution has programmed us to perform those functions at a time when activity would be inefficient and possibly dangerous. However， sleep protects us only from the sort of trouble we might walk into; it does not protect us from trouble that comes looking for us. So we sleep well when we are in a familiar， safe place， but we sleep lightly， if at all， when we fear that bears will nose into the tent.

The evolutionary theory explain the differences in sleep among creatures. Why do cats， for instance， sleep so much， while horses sleep so little？ Surely cats do not need five times as much repair and restoration as horses do. But cats can afford to have long periods of inactivity because they spend little time eating and are unlikely to be attacked while they sleep. Horses must spend almost all their waking hours eating， because what they eat is very low in energy value. Moreover， they cannot afford to sleep too long or too deeply， because their survival depends on their ability to run away from attackers.

1. The author uses the example of the robot in space exploration to tell us .

A. the differences between robots and men

B. the reason why men need to sleep

C. about the need for robots to save power

D. about the danger of men working at night

2. Evolution has programmed man to sleep at night chiefly to help him ．

A. keep up a regular pattern of life

B. prevent trouble that comes looking for him

C. avoid danger and inefficient labor

D. restore his bodily functions

3. Which of the following is the main idea of the passage？

A. Evolution has equipped all creatures with a regular pattern of sleeping and waking

B. The study of sleep is an important art of the evolutionary theory

C. Sleeping patterns must be taken into consideration in the designing of robots

D. The sleeping pattern of a living creature is determined by the food it eats

B

Believe it or not， optical illusion（错觉） can cut highway crashes．

Japan is a case in point. It has reduced automobile crashes on some roads by nearly 75 percent using a simple optical illusion. But stripes， called chevrons（人字形）， painted on the roads make drivers think that they are driving faster than they really are， and thus drivers slow down．

Now the American Automobile Association Foundation（基金会） for Traffic Safety in Washington D.C. is planning to repeat Japans success. Starting next year， the foundation will paint chevrons and other patterns of stripes on selected roads around the country to test how well the patterns reduce highway crashes．

Excessive （too great） speed plays a major role in as much as one fifth of all fatal traffic accidents， according to the foundation. To help reduce those accidents， the foundation will conduct its tests in areas where speedrelated hazards （danger） are the greatest curves， exit slopes， traffic circles， and bridges．

Some studies suggest that straight， horizontal bars painted across roads can initially cut the average speed of drivers in half. However， traffic often returns to full speed within months as drivers become used to seeing the painted bars．

Chevrons， scientists say， not only give drivers the impression that they are driving faster than they really are but also make a lane appear to be narrower. The result is a longer lasting reduction in highway speed and the number of traffic accidents．

1. The passage mainly discusses ．

A. a new way of highway speed control

B. a new pattern for painting highways

C. a new way of training drivers

D. a new type of optical illusion

2. On roads painted with chevrons， drivers tend to feel that ．

A. they should avoid speedrelated hazards

B. they are driving in the wrong lane

C. they should slow down their speed

D. they are coming near to the speed limit

3. The advantage of chevrons over straight， horizontal bars is that the former ．

A. can keep drivers awake

B. can cut road accidents in half

C. will look more attractive

D. will have a longer effect on drivers

4. The American Automobile Association Foundation for Traffic Safety plans to ．

A. try out the Japanese method in certain areas

B. change the road signs across the country

C. replace straight， horizontal bars with chevrons

D. repeat the Japanese road patterns

5. What does the author say about straight， horizontal bars painted across roads？

A. They are suitable only on broad roads

B. They are falling out of use in the United States

C. They are ignored in a long period of time

D. They cannot be used successfully to traffic circles

C

The common cold is the worlds most widespread illness， which is plagues（疫病） that flesh receives．

The most widespread mistake of all is that colds are caused by cold. They are not. They are caused by viruses（病毒） passing on from person to person. You catch a cold by coming into contact， directly or indirectly， with someone who already has one. If cold causes colds， it would be reasonable to expect the Eskimos to suffer from them forever. But they do not. And in isolated Arctic regions explorers have reported being free from colds until coming into contact again with infected people from the outside world by way of packages and mail dropped from airplanes.

During the First World War soldiers who spent long periods in the trenches（战壕）， cold and wet， showed no increased tendency to catch colds.

In the Second World War prisoners at the notorious Auschwitz concentration camp（奥斯维辛集中营）， naked and starving， were astonished to find that they seldom had colds．

At the Common Cold Research Unit in England， volunteers took part in Experiments in which they gave themselves to the discomforts of being cold and wet for long stretches of time. After taking hot baths， they put on bathing suits， allowed themselves to be with cold water， and then stood about dripping wet in drafty room. Some wore wet socks all day while others exercised in the rain until close to exhaustion. Not one of the volunteers came down with a cold unless a cold virus was actually dropped in his nose.

If， then， cold and wet have nothing to do with catching colds， why are they more frequent in the winter？ Despite the most pains―taking research， no one has yet found the answer. One explanation offered by scientists is that people tend to stay together indoors more in cold weather than at other times， and this makes it easier for cold viruses to be passed on.

No one has yet found a cure for the cold. There are drugs and pain suppressors（止痛片） such as aspirin， but all they do is to relieve the symptoms（症状）.

1. The writer offered examples to support his argument.

A. 4B. 5

C. 6D. 3

2. Which of the following does not agree with the chosen passage？

A. The Eskimos do not suffer from colds all the time

B. Colds are not caused by cold

C. People suffer from colds just because they like to stay indoors

D. A person may catch a cold by touching someone who already had one

3. Arctic explorers may catch colds when ．

A. they are working in the isolated Arctic regions

B. they are writing reports in terribly cold weather

C. they are free from work in the isolated Arctic regions

D. they are coming into touch again with the outside world

4. The passage mainly discusses ．

A. the experiments on the common cold

B. the fallacy about the common cold

C. the reason and the way people catch colds

D. the continued spread of common colds

D

Zinc（锌） is one of about 20 elements necessary for good health. It is present in the body in a very small amount but makes it possible for important chemical actions to be carried out in cells. Scientists are just beginning to discover how zinc and other elements work.

Researchers first studied zinc as a way to speed recovery. Dr. Waltor Powys formerly with the United States Air Force noted that the laboratory animals recovered faster when some matters were added to their food. One of these matters was zinc. Dr. Powys later tested the zinc treatment on an American airman recovering from medical operations. The airman who received zinc sulphate（硫酸盐） recovered in half of the usual time. Other doctors studied persons who had a number of strange disorders. The doctors learned that all of these problems were caused by lack of zinc in the body. They treated these disorders successfully by giving the patients zinc sulphate.

The amount of zinc in the body can be found by examining blood and hair. A lack of this important element is not uncommon among people in both industrial and developing countries. Zinc is found in most high protein（蛋白质） foods such as meat， milk， fish and eggs. It is also found in whole grains. But many people do not eat enough of these food. Food markets should add these elements so that more people could get needed amount of these necessary matters.

1. Which of the following statements is true？

A. Scientists found how zinc works a long time ago

B. People need a large amount of zinc to be healthy

C. Zinc allows important chemical actions to take place in cells

D. Zinc must be used in the course of medical operation

2. One of the results from the study of zinc is that .

A. theres only a little zinc in the human body

B. food rich in protein contains more zinc

C. some physical problems are caused by lack of zinc

D. any patient who receives zinc sulphate gets well immediately

3. The best title for the passage may be .

A. A New Discovery

B. Zinc and Health

C. How Zinc Works

D. Add Zinc to Your Food