每种心理状态都有其存在的目的；要理解它，我们必须询问它在更广泛的行为系统中发挥什么功能。
"Every role I take is a piece of my soul that I leave behind."
不用圆规和曲尺，就不能画出方形和圆形。比喻做事要遵循一定的法则。
The development of efficient algorithms is as much an art as it is a science.
The only way to do great work is to love what you do.