The great secret that all old people share is that you really haven't changed in seventy or eighty years. Your body changes, but you don't change at all. And that, of course, causes great confusion.

I don't think you should ever have to apologize for your excitement.

The use of a program to prove the 4-color theorem will not change mathematics - it merely demonstrates that the theorem, a challenge for a century, is probably not important to mathematics.

I’m a fighter, I believe in the power of positivity and hard work.

我不是说唱歌手，我是一个非洲的传奇。

I can't go on, I'll go on.

The American farmer is the only man in our economy who has to buy everything he buys at retail, sell everything he sells at wholesale, and pay the freight both ways.