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

And the best part I would have to say about it is the smiles I put on everybody's faces.

让我说，最好的一点就是我能让人人都微笑，开心。

我就是超人 - SpeakingMax英语口语达人