时间是我们学习的学校，时间是我们燃烧的火焰。

孔子说：“有益的朋友有三种，有害的朋友有三种。与正直的人交朋友、与诚实的人交朋友、与见多识广的人交朋友，有益处；与走邪门歪道的人交朋友、与谗媚奉迎的人交朋友、与花言巧语的人交朋友，有害处。”

People, even more than things, have to be restored, revived, reclaimed and redeemed; never throw out anyone.

我想像鸟儿歌唱一样作画。

Nature has placed mankind under the governance of two sovereign masters， pain and pleasure.

Mathematics is not a deductive science—that's a cliché. When you try to prove a theorem, you don't just list the hypotheses and then start to reason. What you do is trial and error, experimentation, guesswork.