Language is a skin: I rub my language against the other. It is as if I had words instead of fingers, or fingers at the tips of my words.

你有没有为将来打算过呢？

要想成功，你必须无所畏惧。

怀疑是智慧的开端，而非敌人。

数学的研究对科学的发展就像空气或水一样。