All of a sudden, I hear midnight laughter. The sound is muffled, as if not to wake those who sleep; yet all around the air resounds to this laughter.

我忽而听到夜半的笑声，吃吃地，似乎不愿意惊动睡着的人，然而四围的空气都应和着笑。

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Yet sleep scientist Ying-Hui Fu at the University of California, San Francisco,says little is known about the basic need for sleep.

VOA: special.2009.08.26

Well, for a start, there are those eyes, which are famously of a hue that would make a gemologist give little groaning sounds in his sleep, yet the look that they deliver mingles the come-hither with the stay-away.

NEWYORKER: Devotions

Yet sleep has a very long evolutionary history.

NEWYORKER: Up All Night

Yet Blankfein can't sleep some nights, fretful over what could go wrong "when the unforeseeable happens, " he says.

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