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? A. 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. 这是削弱吧?A选项意思是否是:“即使睡觉时A的浓度很低,A链接的sites数量仍然很多”
B. Caffeine, which has the effect of making people remain wakeful, is known to interfere with the binding of adenosine to sites on brain cells. 正确选项,这里是不是算取非削弱? 原文binding…sites增加→sleep Interfere binding…sites→wakeful
C. Besides binding to sites in the brain, adenosine is known to be involved in biochemical reactions throughout the body. biochemical reactions throughout the body无关
D. Some areas of the brain that are relatively inactive nonetheless release some adenosine. 无关
E. Stress resulting from a dangerous situation can preserve wakefulness even when brain levels of bound adenosine are high. 特例
NN,请教一下我分析的对么~~~-- by 会员 UlysessHope (2011/10/30 20:16:37)
Good work. The key is to focus on the conclusion: onset of sleep is caused by A binds to a large number of site.
A) is wrong because it talks about AFTER onset of sleep. |