共用题干Late-night DrinkingCoffee 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 con-trols 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 break-down 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 Medi-cine,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.The author mentions“pick-me-up” to indicate that______.A: melatonin levels need to be raisedB: coffee is a stimulantC: neurohormone can wake us upD: caffeine can balance our brain hormone
共用题干
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 con-trols 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 break-down 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 Medi-cine,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.
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 con-trols 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 break-down 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 Medi-cine,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.
The author mentions“pick-me-up” to indicate that______.
A: melatonin levels need to be raised
B: coffee is a stimulant
C: neurohormone can wake us up
D: caffeine can balance our brain hormone
A: melatonin levels need to be raised
B: coffee is a stimulant
C: neurohormone can wake us up
D: caffeine can balance our brain hormone
参考解析
解析：题干意为“作者提到‘pick-me-up’指出咖啡是一种兴奋剂。”短文第一段第二、三句提到“一天中稍晚的时候来一杯‘提神’咖啡会影响你的睡眠。除了作为一种兴奋剂，咖啡还能阻断褪黑色素的流动”，故选B。
题干意为“下列哪一项告诉我们咖啡是如何影响睡眠的？ 它使体内睡眠激素水平减半。”短文第二段最后一句提到“以色列的研究人员发现，含咖啡因的咖啡能使睡眠激素的水平减半”，而正是这些激素控制我们的睡眠的，故选C。
题干意为“第三段主要讨论什么？”含咖啡因的咖啡与无咖啡因的咖啡对睡眠的不同作用。短文第三段第一句提出“希洛和一个在特拉维夫大学中的萨玉尔医疗中心的团队对6名志愿者进行观察，发现他们喝完一杯含咖啡因的咖啡比喝完相同数量的无咖啡因咖啡时睡得要少”，故选A。
题干意为“第四段提到的实验发现，咖啡因摄入者产生的褪黑色素少。”短文第四段第二、三句提到“希洛测量了志愿者尿液中褪黑色素的一种分解产物的浓度，发现咖啡因摄入者的褪黑色素浓度是无咖啡因摄入者的一半”，故选A。
题干意为“奥哈永建议咖啡爱好者午餐之后喝低咖啡因的咖啡。”短文最后一段提到“因为将咖啡因从体内排除需要几个小时的时间，奥哈永建议咖啡爱好者午餐之后就改换成低咖啡因咖啡”，故选B。
题干意为“下列哪一项告诉我们咖啡是如何影响睡眠的？ 它使体内睡眠激素水平减半。”短文第二段最后一句提到“以色列的研究人员发现，含咖啡因的咖啡能使睡眠激素的水平减半”，而正是这些激素控制我们的睡眠的，故选C。
题干意为“第三段主要讨论什么？”含咖啡因的咖啡与无咖啡因的咖啡对睡眠的不同作用。短文第三段第一句提出“希洛和一个在特拉维夫大学中的萨玉尔医疗中心的团队对6名志愿者进行观察，发现他们喝完一杯含咖啡因的咖啡比喝完相同数量的无咖啡因咖啡时睡得要少”，故选A。
题干意为“第四段提到的实验发现，咖啡因摄入者产生的褪黑色素少。”短文第四段第二、三句提到“希洛测量了志愿者尿液中褪黑色素的一种分解产物的浓度，发现咖啡因摄入者的褪黑色素浓度是无咖啡因摄入者的一半”，故选A。
题干意为“奥哈永建议咖啡爱好者午餐之后喝低咖啡因的咖啡。”短文最后一段提到“因为将咖啡因从体内排除需要几个小时的时间，奥哈永建议咖啡爱好者午餐之后就改换成低咖啡因咖啡”，故选B。