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标题: 麻烦牛人们解释一下这道GWD的题。。 [打印本页]

作者: badman18 时间: 2010-9-1 16:59
标题: 麻烦牛人们解释一下这道GWD的题。。
看到B选项的时候我就觉得是无关的选项，但是为什么答案是B呢，也想不明白是什么逻辑关系。麻烦大牛们解释解释。。

The chemical adenosine is released by brain cells when those cells are active.
Adenosine then binds to more and more sites on cells in certain areas of the
brain, as the total amount released gradually increases during wakefulness.
During sleep, the number of sites to which adenosine is bound decreases. Some
researchers have hypothesized that it is the cumulative binding of adenosine to a
large number of sites that causes the onset of sleep.

Which of the following, if true, provides the most support for the researchers'
hypothesis?


	Even after long periods of sleep when adenosine is at its lowest concentration in the brain, the number of brain cells bound with adenosine remains very large.

	Caffeine, which has the effect of making people remain wakeful, is known to interfere with the binding of adenosine to sites on brain cells.

	Besides binding to sites in the brain, adenosine is known to be involved in biochemical reactions throughout the body.

	Some areas of the brain that are relatively inactive nonetheless release some adenosine.

	Stress resulting from a dangerous situation can preserve wakefulness even when brain levels of bound adenosine are high.

作者: zouchengru 时间: 2010-9-2 00:10
很难的题。
题中论述，醒着，Adenosine增加；睡着，Adenosine减少。研究者的结论是，Adenosine的大量积累导致人的睡眠。
B项提供另一种物质Caffeine，可以保持人清醒且阻碍adenosine。所以Caffeine和adenosine成反比例关系，adenosine积累导致Caffeine少，导致不清醒（睡觉）逻辑上的关系是这样。具体做题方法不知道，因为我也做错了

作者: shirly813 时间: 2010-9-2 18:52
(C)选项throughout the body说明了这是无关选项
(D)选项relatively inactive nonetheless release some adenosine样本不具说服力
(E)选项Stress resulting from a dangerous只说明在压力下的特例,也与题干无关
最后(A)选项是在说明即使在睡眠时adenosine浓度最低,他在脑中的浓度还是非常高,变成是在反驳了
因此只有(B)可选
但这题难在,(B)选项只提到了adenosine和Caffeine有交互关系,却没有说明是正向或负向的关系,在没有厘清其它选项绝对错误时,很难大胆选(B)

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