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。

The best way to learn econometrics is by doing—working with real data and real problems.

The only way to deal with an unfree world is to become so absolutely free that your very existence is an act of rebellion.

The light constantly changes, and that alters the atmosphere and beauty of things every minute.