That is,this kind of pull-yourself-up-by-your-bootstraps, that with enough determination and hard work that you can transcend limitations of money or class or gender.

VOA: special.2010.03.08

It's a little bit easier to pull the ball hard then it is to hit the ball to the opposite field. Yes?

从另一侧击球的话,更容易打出大力球,你还有什么想法

耶鲁公开课 - 博弈论课程节选

Now, to some extent, similarity is hard to pull apart from proximity.

某种程度上，相似性和邻近性是很难区分的。

耶鲁公开课 - 心理学导论课程节选

This proves to be really difficult in the real world because in the real world it's hard to pull apart genes and environments So, you and me will have different personalities ? Why?

这在现实中是很难区分的,因为现实中很难,把基因和环境分开来讲,你和我有不同的性格,为什么？

耶鲁公开课 - 心理学导论课程节选