You've got to make sure that if you explain to others how to do this problem, then somebody else contributes to something else, but you know what everybody contributed in the end.

你得能保证,如果你和别人解释了题目的解法,然后另一个人对别的题目又有独到见解,最后你知道每个人都没有浑水摸鱼

耶鲁公开课 - 基础物理课程节选