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

And they attribute it to the fact that, for all sorts of reasons, the ugly kid just matters less to the parent.

他们把这个现象归因为，不知道为什么，父母就是没那么喜欢丑小孩。

耶鲁公开课 - 心理学导论课程节选

The theory doesn't try to explain why they separated. We don't know Perhaps it was disaffection.

这一理论并着力解释他们为什么分离，我们不知道,也许是因为逆反之意。

耶鲁公开课 - 旧约导论课程节选

So, let's see how some of this works, and hopefully your counterparts from 100 years ago would also be able to think about how this works, even if they don't have the quantum mechanics behind the individual electron configurations for atoms.

那么，下面让我们来看一下它是怎么用的，希望一百年前想你们一样的同学,也能够弄懂它为什么能用，尽管他们没有量子力学,不知道原子的电子排布。

麻省理工公开课 - 化学原理课程节选

I don't know why they make that choice.

我不知道为什么他们做出这样的选择。

麻省理工公开课 - 固态化学导论课程节选

Because they wanted to understand why.

因为他们想知道为什么。

哈佛公开课 - 幸福课课程节选

We detected a 132 000 alpha particles.

他们为什么要这么做？，我们知道。

麻省理工公开课 - 化学原理课程节选