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标题: GMAT-25-36请教求解思路 [打印本页]

作者: sv2000 时间: 2005-11-11 14:35
标题: GMAT-25-36请教求解思路

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 concen-
tration 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: yangsh 时间: 2005-11-11 15:41
B

作者: williamweizh 时间: 2005-11-12 03:26

不太清楚, 有人可以解释一下吗?

作者: 王海波的老婆 时间: 2005-11-12 15:13

选B.

题目说大脑的细胞分泌一种A当这些细胞活跃的时候.当人醒着的时候,分泌的A越来越多,A就bind to越来越多大脑里的sites.在睡觉期间,A bind to的sites越来越少.研究者们就认为是由于A bind to到大量的sites导致了睡觉.问支持.

看选项A说即使在很长的睡眠后,当A处于在大脑中最低的集中状态的时候,A bind to的细胞还是很多.

题中说在睡觉期间,A bind to的细胞是越来越少的.这里说很多.无法支持结论.

B说咖啡因能让人保持清醒,防碍了A bind to细胞上的sites的,防碍了A去bind to sites,也就防碍了睡眠.支持了结论A bind to 细胞上的sites到一定数量导致了睡眠.

C说A除了bind to sites这个功能还有别的功能,这个无关.

D说大脑里的一些相对inactive不活跃的areas也能分泌A.题中说睡觉的时候A bind to sites的数量减少,如果睡觉的时候也能分泌A,那怎么会越来越少呢.

E说危险情况带来的压力能够使人保持清醒,即使大脑中的A很高.结论说是A很高导致睡眠,这里说A很高无法导致睡眠,weaken.

大家一起讨论吧,手都写酸了,不知道说清楚没有.

作者: sv2000 时间: 2005-11-13 08:46

谢谢4楼的解释。见过波波，但没见过他老婆，呵呵！

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