数学中最重要的是理解概念，而不仅仅是记忆公式。

无论你来自哪里，音乐都能带你到你想去的地方。

What we have to remember is that we can still do anything. We can change our minds. We can start over.

The art of doing mathematics consists in finding that special case which contains all the germs of generality.

美联储的工作就是在派对刚开始时把酒杯拿走。