The world's history is the world's judgment.

Don't search for defining moments because they will never come. The moment that define you have already happened, and they will already happen again.

A good mathematician should be both rigorous and imaginative.

The thing about life is that it's never the way you think it's going to be.

I want to liberate America from fear. I want people to feel free to express themselves.

可持续发展不再是选择，而是任何希望长期繁荣的企业的必需品。