善意并不是自己内心发出的，不能保留；行为自身不能够理解和辨别的，不能去做。

It’s not just what you say that stirs people. It’s the way that you say it.

The only way to achieve the impossible is to believe it is possible.

Freedom is the right to tell people what they do not want to hear.

在数学中，提出问题的艺术必须比解决问题更有价值。