Quality is free. It's not a gift, but it's free. What costs money are the unquality things -- all the actions that involve not doing jobs right the first time.

可归约性的概念对于理解不同计算问题之间的关系至关重要。

成长就是丢掉一些幻想，以便获得另一些。

人生就是一场马拉松，别急，慢慢跑。