专四考前恶补阅读完型(1)(3)
文章出处： 发布时间：2006-07-09
C. They began to specialize in private investment.
D. There were insufficient numbers of trained people to operate them.
18. Why does the author mention the Sierra Nevada in line 17?
A. To argue that a more direct route to the West could have been taken.
B. To identify a historically significant mountain range in the West.
C. To point out the location of a serious train accident.
D. To give an example of an obstacle faced by the central pacific.
19. The word “subsidy” in line 27 is closest in meaning to _____.
A. persuasion B. financing C. explanation D. penalty
TEXT B
Certainly no creature in the sea is odder than the common sea cucumber. All living creature, especially human beings, have their peculiarities, but everything about the little sea cucumber seems unusual. What else can be said about a bizarre animal that, among other eccentricities, eats mud, feeds almost continuously day and night but can live without eating for long periods, and can be poisonous but is considered supremely edible by gourmets?For some fifty million years, despite all its eccentricities, the sea cucumber has subsisted on its diet of mud. It is adaptable enough to live attached to rocks by its tube feet, under rocks in shallow water, or on the surface of mud flats. Common in cool water on both Atlantic and Pacific shores, it has the ability to suck up mud or sand and digest whatever nutrients are present.Sea cucumbers come in a variety of colors, ranging from black to reddishbrown to sandcolor and nearly white. One form even has vivid purple tentacles. Usually the creatures are cucumbershaped—hence their name—and because they are typically rock inhabitants, this shape, combined with flexibility, enables them to squeeze into crevices where they are safe from predators and ocean currents.
Although they have voracious appetites, eating day and night, sea cucumbers have the capacity to become quiescent and live at a low metabolic rate—feeding sparingly or not at all for long periods, so that the marine organisms that provid their food have a chance to multiply. If it were not for this faculty, they would devour all the food available in a short time and would probably starve themselves out of existence.
But the most spectacular thing about the sea cucumber is the way it defends itself. Its major enemies are fish and crabs, when attacked, it squirts all its internal organs into water. It also casts off attached structures such as tentacles. The sea cucumber will eviscerate and regenerate itself if it is attacked or even touched; it will do the same if the surrounding water temperature is too high or if the water becomes too polluted.
20. According to the passage, why is the shape of sea cucumbers important?
A. It helps them to digest their food.
B. It helps them to protect themselves from danger.
C. It makes it easier for them to move through the mud.
D. It makes them attractive to fish.
21. The fourth paragraph of the passage primarily discusses ____.
A. the reproduction of sea cucumbers
B. the food sources of sea cucumbers
C. the eating habits of sea cucumbers
D. threats to sea cucumbers’ existence
22. What can be inferred about the defence mechanisms of the sea cucumber?
A. They are very sensitive to surrounding stimuli.
B. They are almost useless.
C. They require group cooperation.
D. They are similar to those of most sea creatures.
23. Which of the following would NOT cause a sea cucumber to release its internal organs into the water?
A. A touch. B. Food.
C. Unusually warm water. D. Pollution.
TEXT C
Human beings have used tools for a very long time. In some parts of the world you can still find tools that people used more than two million years ago. They made these tools by hitting one stone against another. In this way, they broke off pieces from one of the stones. These chips of stone were usually sharp on one side. People used them for cutting meat and skin from dead animals, and also for making other tools out of wood. Human beings needed to use tools because they did not have sharp teeth like other meateating animals, such as lions and tigers. Tools helped people to get food more easily.
Working with tools also helped to develop human intelligence. The human brain grew bigger, and human beings began to invent more and more tools and machines. The stone chip was one of the first tools that people used, and perhaps it is
the most important. Some scientists say that it was the key to success of mankind.
Since 1960 a new kind of tool has appeared. This is the silicon chip—a little chip of silicon crystal. It is smaller than a fingernail, but it can store more than a million “bits” of information. It is an electronic brain.Every year these chips get cleverer, but their size gets smaller, and their cost gets less. They are used in watches, calculators and intelligent machines that we can use in many ways.
In the future we will not need to work with tools in the old way. Machines will do everything for us. They will even talk and play games with us. People will have plenty of spare time. But what will they do with it?
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