译文：知识只有到实际运用的时候才会后悔自己当初读得太少了，事情如果没有亲身经历就不知道其中的艰难。赏析：年少时，我们不知道读书的意义，等到出生社会以后才明白读书的好处。人生很多事情，看似简单，但当我们真正地去做的时候，才发现并非易事。

If you borrow something， try to return it in better shape than you received it. Clean it， sharpen it， fill it up.

学习数学的唯一方法就是做数学。

The study of psychology is not just about understanding others; it's also about understanding ourselves and how we interact with the world around us.