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2017年英语四级阅读练习和答案解析
Modern scientists divide the process of dying into two stages—clinical or (emporary death and biological death. Clinical death occurs when the vital organs, such as the heart or lungs, have ceased to function, but have not suffered permanent damage. The organism can still be revived (复活). Biological death occurs when changes in the organism lead to the disintegration(解体) of vital cells and tissues. Death is then irreversible and final.
Scientists have been seeking a way to prolong the period of clinical death so (hat the organism can be revived before biological death occurs. The best method developed so far involves cooling of the organism, combined with sleep. By slowing down the body’s metabolism(新成代谢) , cooling delays the processes leading to biological death.
To illustrate how this works, scientists performed an experiment on a six-year-old female monkey called Keta. The scientists put Keta to sleep. Then they surrounded her body with ice-bags and began checking her body temperature. When it had dropped to 28 degrees the scientists began draining blood from an its body. The monkey’s blood pressure decreased and an hour later both the heart and breathing stopped; clinical death set in. For twenty minutes Keta remained in this state. Her temperature dropped to 22 degrees. At this point the scientists pumped blood into its body in the direction of the heart and started artificial breathing. After two minutes the monkey’s heart became active once more. After fifteen minutes, spontaneous breathing began, and after four hours Keta opened her eyes and lifted her head. After six hours, when the scientists tried to give her a penicillin injection, Keta seized the syringe and ran with it around the room. Her behavior differed little from that of a healthy animal.
26. This passage focuses on_______.
A. the difference between biological and clinical death.
B. the process of dying
C. prolonging the period of clinical death
D. the nature of clinical death
27. The best statement of the main idea of this passage is that
A. modem scientists divide the process of dying into clinical and biological death
B. biological death occurs when vital organs have suffered permanent damage
C. scientists have found a way to prolong the period of clinical death
D. cooling delays the processes leading to biological death
28. One characteristic of clinical death is______.
A. lasting damage to the lungs B. destruction of the tissues
C. temporary non-functioning of the heartD. that the organism cannot be revived
29. According to the passage, cooling an organism
A. speeds up the body’s metabolism B. slows disintegration of body tissues
C. prevents damage to organs D. revives damaged organs
30. One possible benefit of the experiment discussed in the passage is______.
A. less crowded cities B. victory over death
C. protection against fatal injury D. fewer deaths from heart attacks
答案：
26. C 27. C 28. C 29. B 30. D
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