It was too cold for them to sleep much.

VOA: special.2009.07.22

There's a guy in about the fifth row there who's missed too much sleep, so somebody just nudge him. That's it, good.

第五排有一个同学,可能很缺乏睡眠吧,旁边的人把他叫醒吧

耶鲁公开课 - 博弈论课程节选