第一篇:《005-阅读理解-第五篇 在深夜饮咖啡》
第五篇-Night Drinking
Coffee lovers beware〔当心〕. Having a quick "pick-me-up" cup of coffee late in the day will play havoc〔破坏〕with your sleep. As well as being a stimulant〔〕, caffeine interrupts〔打断〕 the flow of melatonin〔褪黑激素〕,the brain hormone〔荷尔蒙〕that sends people into a sleep.
Melatonin levels normally start to rise about two hours before bedtime. Levels then peak（山峰）betweenn2 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（志愿者）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 4l5 minutes after decaf. They also took half an hour to drop off- twice as long as usual -and jigged around in bed twice as much.
In the second phase(阶段)of the experiment, the researchers woke the volunteers every three hours and asked them to give a urine(尿) sample. Shilo measured
concentrations（浓度）of a breakdown（分解）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 that drives melatonin production.
Because it can take many hours to eliminate（排除）caffeine from the body, Ohayon recommends that coffee lovers switch to decaf after lunch.
练习:
l. The author mentions "pick-me-up" to indicate（表明）that
A melatonin levels need to be raised.
B neurohormone can wake us up.
C coffee is a stimulant.
D decaf is a caffeinated coffee.
2. Which of the following tells us how caffeine affects sleep?
A Caffeine blocks production of the enzyme that stops melatonin production.
B Caffeine interrupts the flow of the hormone that prevents people from
sleeping.
C Caffeine halves the body's levels of sleep hormone.
D Caffeine stays in the body for many hours.
3. What does paragraph 3 mainly discuss?
A Different effects of caffeinated coffee and decaf on sleep.
B Different findings of Lotan Shilo and a team about caffeine.
C The fact that the subjects slept 4l5 minutes per night after drinking decaf.
D The proof that the subjects took half an hour to fall asleep.
4. What does the experiment mentioned in paragraph 4 prove?
A There are more experiment in decaf drinkers' urine sample.
B There are more melatonin concentrations in caffeine drinkers' urine sample.
C Decaf drinkers produce less melatonin.
D Caffeine drinkers produce less sleep hormone.
5. The author of this passage probably agrees that
A coffee lovers sleep less than those who do not drink coffee.
B we should not drink coffee after supper.
C people sleep more soundly at midnight than at 3 am.
D if we feel sleepy at night , we should go to bed immediately.
第五篇在深夜饮咖啡
咖啡爱好者注意了。在深夜喝一杯快速提神的咖啡会严重影响你的睡眠，跟一样，咖啡因会扰乱褪黑激素的自由流动，这种褪黑激素是大脑里促人睡眠的一种荷尔蒙。
在上床睡觉前约2 小时的时候褪黑激素含量开始上升，在凌晨2 点到4 点达到最高值，然后再次下降。加州斯坦福大学斯坦福睡眠流行病学研究中心的Maurice Ohayon 说"控制我们睡眠的'是神经激素，它告诉我们的身体什么时候睡觉，什么时候醒来。"而以色列的研究人员发现含咖啡因的咖啡使这种睡眠荷尔蒙浓度降至一半。
Lotan Shilo 和Tel Aviv 大学"Sapir医学中心"的一组人员，在给六位志愿者做实验时发现，他们在饮了咖啡因的咖啡后比饮了脱咖啡因的咖啡后睡眠质量要差。平均来说，在喝了含咖啡因的咖啡后每晚睡眠时间为336 分钟，而喝了脱咖啡因的咖啡后则睡415 分钟。同时他们得花半个小时入睡，是通常情况的两倍。另外，他们在床上辗转次数也要长一倍。
在实验的第二阶段，研究人员每三个小时便叫醒一次志愿者，并叫他们提供尿样。Shilo 检验了他们褪黑激素分解产物的浓度，结果显示，咖啡因摄入者体内的褪黑激素是非咖啡因摄入者的一半。在《睡眠医学》刊物上发表的文章中，研究人员暗示说，褪黑激素的生成由酶来促成，而咖啡因阻止了酶的生成。
因为要花许多小时的时间才能将身体中的咖啡因除去， Ohayon 建议咖啡爱好者应在午后换喝脱咖啡因的咖啡。
第五篇Late-Night Drinking
Coffee lovers beware〔当心〕. Having a quick "pick-me-up" cup of coffee late in the day will play havoc with your sleep. As well as being a stimulant, caffeine interrupts the flow of melatonin,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 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. On average, subjects slept 336 minutes per night after drinking caffeinated coffee, compared with 4l5 minutes after decaf. They also took half an hour to drop off- twice as long as usual -and jigged around in bed twice as much.
In the second phase of the experiment, the researchers woke the volunteers every three hours and asked them to give a urine sample. Shilo measured concentrationsof 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 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.
学识谷
