共用题干第二篇Late-night DrinkingCoffee lovers,be careful.Having a quick "pick-me...

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问题共用题干第二篇

Late-night Drinking

Coffee lovers,be careful.Having a quick "pick-me-up" cup of coffee late in the day will interrupt your
sleep. As well as being a stimulant（兴奋剂）,caffeine interrupts the flow of melatonin（褪黑激素）,the
brain hormone that sends people into a sleep.
Melatonin levels normally start to rise about two hours before bedtime.Levels then peak between 2 am
and 4 am , before falling again. " It 's the neurohormone（神经激素）that controls our sleep and tells our
body when to sleep and when to wake,"says Maurice Ohayon of the Stanford Sleep Epidemiology Research
Center at Stanford University in California. But researchers in Israel have found that caffeinated coffee halves
the body'S levels of this sleep hormone.
Lotan Shilo and a team at the Sapir Medical center in Tel Aviv University found that six volunteers slept
less well after a cup of caffeinated coffee than after drinking the same amount of decaf（脱咖啡因咖啡）.On
average,subjects slept 336 minutes per night after drinking caffeinated coffee,compared with 415 minutes
after decaf. They also took half an hour to drop off,twice as long as usual.
In the second phase of the experiment,the researchers woke the volunteers every three hours and asked
them to give a urine（尿）sample.Shilo measured concentrations of a breakdown product of melatonin.The
results suggest that melatonin concentrations in caffeine drinkers were half those in decaf drinkers.In a paper
accepted for publication in Sleep Medicine,the researchers suggest that caffeine blocks production of the
enzyme（酶）that drives melatonin production.
Because it can take many hours to eliminate caffeine from the body.Ohayon recommends that coffee
lovers switch to decaf after lunch.

选项 What does Paragraph 3 mainly discuss? A:Different effects of caffeinated coffee and decaf on sleep. B:Lotan Shilo'S research design on sleep. C:What the subjects did after drinking decaf at night. D:Why some subjects took half an hour to fall asleep.

答案 A

解析 pick-me-up 指提神饮料，也就是一种刺激物，在这篇文章里具体指咖啡。故选B。
文章第二段的第三句话讲到，“控制我们睡眠的是神经激素”，而这一段的最后一句话告诉我们“含咖啡因咖啡能使这种睡眠激素减半”。这正是咖啡因影响睡眠的原理，故选C。
第三段涉及一个实验，这个实验的目的是测试含咖啡因咖啡和脱咖啡因咖啡对睡眠的影响，该段主要谈论的是这个实验的结果。故选A。
第四段是第三段实验的继续，是该实验的第二个阶段。研究人员通过对志愿者的尿进行化验发现，咖啡因摄入者体内的褪黑激素（melatonin）仅为非咖啡因摄入者的一半。故选A。
文章最后一段最后一句话说："Ohayon建议爱喝咖啡的人午饭后应该换喝脱咖啡因咖啡”。故选B。第三篇本文主要讲述了阿司匹林作为一种止痛药，它的发明及畅销过程，以及发现它可以治疗心脏病发作的事情。

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共用题干第二篇Late-night DrinkingCoffee lovers,be careful.Having a quick "pick-me...