Happiness is like a butterfly; the more you chase it, the more it will elude you. But if you turn your attention to other things, it will come and sit softly on your shoulder.

数学是一门活生生的学科，随着新的思想和发现不断演变。

I don't wait for moods. You accomplish nothing if you do that. Your mind must know it has got to get down to work.

"Every family has its secrets, but in some countries, the secrets are bigger and more dangerous."

The more you know, the more you can know.