[外语类试卷]大学英语四级改革适用(阅读)模拟试卷52及答案与解析.doc
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1、大学英语四级改革适用(阅读)模拟试卷 52及答案与解析 Section C 0 Imagine an animal that becomes frozen in cold weather. Then, when it gets warmer, the animal simply unfreezes and goes back to its normal life. Although this may sound like something from a science-fiction movie, it is exactly what happens to the wood frog ove
2、r winter and spring. When winter begins, the frog, which is found throughout much of Canada, buries itself in leaves and dirt. As the ground begins to freeze, so does the frog s body. Normally, if a living creature is frozen, the cells inside its body are destroyed, leading to death. How, then, does
3、 the wood frog survive? The secret lies in the fact that although the water between the cells in the frog s body becomes frozen, the water inside the cells does not freeze. Before the winter begins, the frog stores starch in its body. As the weather gets colder, the drop in temperature causes the fr
4、og s body to change this starch into glucose. This glucose, in turn, lowers the temperature at which the liquid inside the frogs cells freezes. As a result, the cells do not freeze even at very low temperatures, allowing the frog to stay alive. Some wood frogs stay in this frozen state with their he
5、arts stopped completely for months without harm. Now researchers are hoping to adapt the wood frog s secret to help them preserve human organs for transplants. Currently, after organs are removed from a donor s body, they are packed in a special liquid and kept very cold. However, they cannot be fro
6、zen because the ice would damage the cells in the organs. For this reason, the organs must be used quickly. If doctors had a way to preserve organs longer, they would have more time to find the best matches among people waiting for organ transplants. There is still a lot about the wood frog that sci
7、entists do not understand. They still have to work out, for example, exactly how the frog is able to unfreeze itself and what actually restarts the frogs heart when the weather becomes warmer. What is clear, however, is that lessons learned by studying this tiny creature could be of great benefit to
8、 humans in the near future. 1 The wood frog is unusual because it_. ( A) can move about easily on frozen ground ( B) buries itself in leaves and dirt at the start of spring ( C) survives even after its body has become frozen ( D) lives a normal life even in very cold weather 2 What effect does the g
9、lucose produced in the wood frog s body have? ( A) It stops the water in the frog s cells from freezing in cold weather. ( B) It lowers the temperature in the spaces between the frog s cells. ( C) It causes the frog s cells to produce more starch. ( D) It allows the frog s cells to produce more wate
10、r. 3 Researchers are hoping to use the wood frog s secret to allow them to_. ( A) use transplant organs more quickly ( B) remove organs from a donor more easily ( C) unfreeze transplant organs with chemicals from the frogs ( D) keep transplant organs longer than they can now 4 Which is one thing tha
11、t scientists would like to find out about the wood frog? ( A) Whether it becomes frozen in the spring. ( B) How its heart starts again when it unfreezes. ( C) Which parts of its body freeze in cold weather. ( D) Why it takes so long to unfreeze at the end of winter. 5 Which of the following is true?
12、 ( A) The wood frog needs starch in order to stop the cells in its body from dying. ( B) Researchers are trying to find a way to transplant the organs of wood frogs. ( C) Wood frogs use the glucose in their cells to unfreeze their bodies at the end of winter. ( D) Scientists are now using the proces
13、s that takes place in a wood frogs body to prepare human organs for transplant. 5 Since ancient times, the destructive effects of earthquakes on human lives and property have encouraged the search for reliable methods of earthquake prediction. This challenge remains and modern scientists continue to
14、 search for reliable methods to determine the time, place and intensity of individual quakes. One prediction technique involves an analysis of the recurrence(重现 )rates of earthquakes as indicators of future activity. Earthquakes are concentrated in certain areas of the world which are subject to con
15、stant movements of earth s plates and it is in these areas that scientists focus their investigations. This search for pre-earthquake phenomena has received particular attention. In contrast to the ancient Greeks and Romans, who relied on the crying of dogs as a warning sign, modern scientists have
16、focused on physical evidence for a coming earthquake. Evidence of plate strain can be found by measuring relative movements, while chemical changes also offer signals for scientists. Analysis of the changes in magnetic properties and conductivity(传导性 )of rocks provides further data for prediction. T
17、he electrical and magnetic properties of crustal(地壳的 )rocks are particularly sensitive to strain. The conductivity of crustal rock is determined by the degree to which the rock is soaked with fluid and the electrolytic properties of those fluids. Before large earthquakes, small fractures develop in
18、rocks, which change the quantity of fluid present. These changes can be measured and provide useful data. However, similar changes in the fluid, bearing capacity of rock can occur as a result of other factors such as changes in the water table, and therefore this technique is not entirely reliable.
19、The ancient believe that the behavior of birds, cats and dogs provides evidence of inevitable earthquakes has recently been attended as a result of tests carried out in California. It has been shown that changes taking place in the metabolic(新陈代谢的 )rates of these animals correlate with subsequent se
20、ismic activity. It is assumed that the animals are sensitive to the seismic waves which precede major quakes. In zones where earthquakes are known to occur, improved construction techniques can significantly reduce the effects of seismic waves. If more accurate information regarding the time and int
21、ensity were available, governments could take even more effective measures to reduce the impact on human life, if, however, an entirely accurate prediction technique became available, there would be significant social and political implications. 6 Recurrence rates of earthquakes can help predict fut
22、ure quakes because_. ( A) improvement in mathematics allows figures to be more accurate ( B) this method has been used since ancient times and proved very effective ( C) most scientists focus their investigations on the quakes of certain areas ( D) continuous plate movements often result in earthqua
23、kes in certain areas 7 Which of the following is used by modern scientists to indicate a coming earthquake? ( A) The crying of dogs. ( B) The conductivity of rocks. ( C) The changes in the water table. ( D) The quantity of fluid in earth. 8 Crustal rocks can be used to predict earthquakes for their_
24、. ( A) conductivity of electricity ( B) sensitivity to strain ( C) hardness to be cracked ( D) magnetic properties 9 A disadvantage of fluid measuring is that_. ( A) changes in quantity of fluid in rocks can be caused by other factors other than strain ( B) present scientific instruments are not abl
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- 外语类 试卷 大学 英语四 改革 适用 阅读 模拟 52 答案 解析 DOC
