2. 考研
  3. The Earth’s daily clock, measured in a single revolution, is twenty-four hours. The human clock,【B1】______, is actually about tw

The Earth’s daily clock, measured in a single revolution, is twenty-four hours. The human clock,【B1】______, is actually about tw

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问题     The Earth’s daily clock, measured in a single revolution, is twenty-four hours. The human clock,【B1】______, is actually about twenty-five hours. That’s【B2】______scientists who study sleep have determined from human subjects who live for several weeks in observation chambers with no 【B3】______ of day or night. Sleep researchers have 【B4】______ other surprising discoveries as well.
    We spend about one-third of our lives asleep, a fact that suggests sleeping,【B5】______eating and breathing, is a fundamental life process. Yet some people almost never sleep, getting by on as 【B6】______ as fifteen minutes a day. And more than seventy years of【B7】______into sleep deprivation, in which people have been kept 【B8】______ for three to ten days, has 【B9】______ only one certain finding: Sleep loss makes a person sleepy and that’s about all; it causes no lasting ill【B10】______. Too much sleep, however, may be【B11】______for you.
    These findings【B12】______some long-held views of sleep, and they【B13】______questions about its fundamental purpose in our lives. In【B14】______, scientists don’t know just why sleep is necessary.
    Some scientists think sleep is more the result of evolutionary habit than【B15】______actual need, Animals sleep for some parts of the day perhaps because it is the【B16】______thing for them to do: it keeps them【B17】______and hidden from predators; it’s a survival tactic. Before the advent of electricity, humans had to spend at least some of each day in【B18】______and had little reason to question the reason or need for【B19】______. But the development of the electroencephalograph and the resulting discovery in 1937 of dramatic【B20】______in brain activity between sleep and wakefulness opened the way for scientific inquiry in the subject.
【B16】
选项 A、worst
B、best
C、only
D、natural
答案B
解析 此处句意为“动物在一天中的某些时候睡觉，可能是因为睡觉对于它们来说是______的事”。根据下文的hidden from predators(躲开食肉动物)，it’s a survival tactic(这是一条生存策略)可知B．best符合题意，为正确答案。
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考研英语一

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