And I don't know why, but since time immemorial that is the way computer scientists have drawn trees.

叶子是在最下面的，我不知道为什么,但从记事以来他们就是这么画树的,这也许就是为什么我们。

麻省理工公开课 - 计算机科学及编程导论课程节选

In fact, I do this as well, I mean I have water with me and I have no idea why because I'm not particularly dehydrated.

事实上,我也整天带着水壶,我是说我随身带水,但又不知道为什么要带,因为我并没有特别的脱水症状

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选