Barbara Klein has more. The band that brought us one of the best albums of the decade is back with a new CD, It is Green Day's eighth studio album.

VOA: special.2009.05.29

Probably the best answer is our body is worn out during the day and sleep is necessary to put it back into shape.

最佳的答案应该是,一天下来，我们的身体已经疲惫了,有必要进行睡眠，以恢复状态。

耶鲁公开课 - 心理学导论课程节选