A new study found better results in four-year-olds who go to bed around the same time every night and sleep at least eleven hours.

VOA: special.2010.06.09

On day four, The heavenly bodies that give off light by day or night are created.

在第四天，那些在白天或者晚上发光的天体被创造了。

耶鲁公开课 - 旧约导论课程节选

If you want to remember your dream by the way keep your dreams--keep a dream diary, very useful, but everybody dreams three to four times a night.

如果你想记得自己梦见什么,那就写一本梦境日记，这是非常有用的，每个人平均一晚作三四次梦。

耶鲁公开课 - 心理学导论课程节选

One night in eighteen sixty-four, President Lincoln survived an assassination attempt.

VOA: special.2010.05.10

And for the space of four hours every night, I feel no boredom.

每晚四小时的学习，我一点也不觉得无聊。

耶鲁公开课 - 政治哲学导论课程节选

Recent studies say four hundred or more people died that night.

VOA: special.2009.11.11