抱最好的希望，做最坏的打算。

The concept of NP-completeness has provided a powerful tool for understanding the complexity of problems.

The person who tries to live alone will not succeed as a human being. His heart withers if it does not answer another heart. His mind shrinks away if he hears only the echoes of his own thoughts and finds no other inspiration.

 大胆行动，全心全意地投入，连上苍也会受感动。

A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.

暴君死了，他的统治结束了；殉道者死了，他的统治开始了。

All my life through, the new sights of Nature made me rejoice like a child.