He was extremely tired but sleep eluded him.

他累极了，却睡不着。

《牛津词典》

As is often the case with human beings, many animals sleep a lot when young, but sleep much less when they get older.

和人类一样，许多动物年幼时睡得多，但长大后睡少了很多。

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Right now, to reduce the risk of sudden infant death syndrome, the American Academy of Pediatrics recommends that mothers not sleep in the same bed as their babies but sleep in the same room.

现在，为了降低婴儿猝死综合症的风险，美国儿科学会建议母亲不要和她们的宝宝睡在同一张床上，但可以睡在同一个房间里。

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Many people could do nothing but sleep.

VOA: special.2010.07.31

But my only criterion is if you talk in your sleep, now that's not allowed because talking is not allowed.

我唯一的要求就是别说梦话,因为我的课上不准说话的

耶鲁公开课 - 基础物理课程节选

But think of the various periods during the night in which you are in a deep, deep dreamless sleep.

但请设想你处在这样的夜晚,你处于熟睡，安枕无梦。

耶鲁公开课 - 死亡课程节选

But sleep was running away from Oknov.

NEWYORKER: So It Is in Life

Dr. Sanjay Gupta, CNN chief medical correspondent: You're not likely to have a doctor ever advise giving the sleep hormone melatonin to your teenagers, but sleep experts tell CNN they've seen a tremendous upsurge in the use of melatonin in kids, by parents.

CNN: Should your teen take melatonin for help with sleep?

The average adult sleeps seven hours a night but many sleep considerably less than this, especially people over 50.

BBC: Thatcher: Can people get by on four hours' sleep?