数学家的工作永无止境；总有新的问题要问，新的谜题要解。

一个没有记忆的国家是没有未来的国家。

Change is not made without inconvenience, even from worse to better.

As to the gods, I do not know whether they exist or not, nor what they are like in form; for there are many things that hinder sure knowledge, the obscurity of the matter and the shortness of human life.

可持续性不是一种选择，而是一种责任。