四、阅读理解(共15题，每题3分，共45分)

　　阅读下列短文，然后根据短文的内容从每题的四个选项中选出最佳的一项。

　　Passage 1

　　There are millions of pain nerves in the body, and when any of them are even slightly disturbed, they flash a pain impulse to the brain. The brain weighs this message, evaluates it in terms of so much pain or discomfort. When a state of tension exists, it causes the brain to overvalue pain impulses --- thus causing you to feel far more uncomfortable than you otherwise would. On the other hand, when you are relaxed, pain messages tend to be evaluated on a much lower scale. Tests show that up to 75 percent of the pain (or disagreeable sensation) which exists when a person is tense vanishes entirely when he relaxes.

　　56. The author of this passage is most interested in telling us about _______.

　　A. the result of tests carried out on tense persons

　　B. the way the pain nerves work

　　C. the relationship of the brain to the pain feeling

　　D. the effect of tension on comfort or discomfort

　　57. The main idea of the passage is that ________.

　　A. the brain evaluates each pain signal in terms of so much pain or discomfort

　　B. the brain evaluates a pain impulse in accordance with the degree of tension in the body

　　C. tests show that up to 75 percent of pain which exists when a person is tense vanishes when he relaxes

　　D. the millions of pain nerves in the body are each able to flash a pain message to the brain when even slightly disturbed

　　58. To reduce pain, it would be probably best to _______.

　　A. evaluate pain messages on a lower scale

　　B. build up tension in your body

　　C. learn to relax

　　D. increase your sense of mental well-being

　　59. We can conclude from the passage that a person s feeling of discomfort _______.

　　A. is the result of bodily states beyond his control

　　B. is controlled by his brain and thus is beyond his influence

　　C. is influenced by his mental and emotional state

　　D. depends on how the individual evaluates it

　　60. When people relax, _______.

　　A. pain messages tend to be evaluated on a much lower scale

　　B. pain nerves are slightly disturbed

　　C. they feel far more uncomfortable

　　D. the pain still exists

　　Passage 2

　　There are many ways of putting out a fire. You may have seen people put out burning cigarettes by stepping on them. Stepping on a burning cigarette shuts off the air and puts out the fire. Many fires are put out with water. Water cools the material that is burning. It helps smoother a fire, too. Some of the water is changed into steam when it strikes the hot fire. The steam shots off air from the fire and helps put it out.

　　Some fires cannot be put out with water. They have to be smothered with sand or with chemicals of some kind, such as those used in some fire extinguishers. Suppose a tank full of gasoline is on fire. Gasoline is lighter than water. If you poured water into the tank of gasoline, the water would sink to the bottom of the tank. The gasoline would float on top of the water and would probably keep on burning. If you keep on putting water on the fire, the gasoline would flow over the edge of the tank. Then the fire would spread.

　　61. What are the major ways of putting out fires as mentioned in the passage?

　　A. With water and sand and chemicals.

　　B. With water and sand and steam.

　　C. With water and steam.

　　D. With water and materials and chemicals.

　　62. Water can put out a fire because .

　　A. water is cold and cool

　　B. water is the only way to put out a fire

　　C. water cools the material on fire and the steam shuts off air

　　D. water can be changed into steam

　　63. Gasoline fires cannot be put out with .

　　A. sand B. water C. chemicals D. extinguisher

　　64. If you put water into the tank of gasoline, .

　　A. gasoline would sink to the bottom of the tank

　　B. gasoline would be mixed with water

　　C. water would float on the top of gasoline

　　D. water would not be mixed with gasoline

　　65. The best title of the passage would be .

　　A. Water and Fire B. How to Put Out a Fire

　　C. Gasoline on Fire D. Why Can Water Put Out Fire