An elderly person may nap during the day and then sleep only five hours a night.

上了年纪的人白天会小睡一会儿，然后晚上只睡5个小时。

《柯林斯英汉双解大词典》

To further confuse the issue, there is an enormous variation in the amount of sleep people feel happy with.

使这个问题进一步复杂化的是，人们感觉愉快的睡眠时间相差很大。

《柯林斯英汉双解大词典》

Other studies have found that even infants in East Asia sleep about an hour less than European infants.

其他研究发现，即使是东亚的婴儿也比欧洲的婴儿少睡一小时左右。

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On the other hand, those who aren't getting seven hours of sleep may be kept up by another condition -- anxiety, sleep apnea, or an undiagnosed illness -- that could be the real risk factor.

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On the pro sleep-training side, an Australian study published in September followed 326 children with parent-reported sleep problems at 7 months.

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When you need to take a break, close the lid and VAIO goes into an energy-efficient deep sleep, keeping your data stored safely for up to 90 days1 without running out of power.

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