The best time to plant a tree was twenty years ago. The second best time is now.

The only way to tell the truth is to speak without a mouth.

希望是最后消亡的东西。

这些墙很有趣。刚入狱的时候，你痛恨周围的高墙；慢慢地，你习惯了生活在其中；最终你会发现自己不得不依靠它而生存。这就叫体制化。

The personal example of a teacher is the most useful sunshine that nothing can replace for the soul of young people.

世界需要科学，科学也需要世界。