国际体系本质上是竞争性的，国家不断试图互相超越。

我总是相信，如果你陷入困境，也许事情并不顺利，你会变得更强大。

One ought never to turn one's back on a threatened danger and try to run away from it. If you do that, you will double the danger. But if you meet it promptly and without flinching, you will reduce the danger by half.

写作是探索生命奥秘的一种方式。

I don't think that everyone should become a mathematician, but I do believe that many students don't give mathematics a real chance.