最简单的词语往往承载最重的分量。
效率是把事情做对；效能是做对的事情。
写作是我存在于世界的方式。
计算效率的概念是学习算法设计的核心。
The most necessary, the most important, the principal, the most essential thing for a musician is this: to know what he wants, what he can do, and what he ought to do.