过去总是紧张的，而未来是完美的。

Mathematics is not about numbers, equations, computations, or algorithms: it is about understanding.

在每个故事中，都有作者的一片心，他们灵魂的一角裸露给世界看。

Well, the first rule is that you can’t really know anything if you just remember isolated facts and try and bang ’em back. If the facts don’t hang together on a latticework of theory, you don’t have them in a usable form.

所以，储备是国家最重要的事；粮食是国家的宝物；武器是国家的利爪；城池是守卫国家的屏障。