International politics is a brutal and unforgiving arena, where states constantly strive to maximize their power and security.

贫贱时，对富贵漠然置之，他日得志一定不自矜；富贵之时，心中不忘贫贱之日，即便失却富贵心中也必无怪怨。

数学中的每个问题都是一个等待解决的谜题，而乐趣就在于解决的过程。