生命短暂，但如果我们活得正确，一次就足够了。
Life is short, but if we live it right, once is enough.
"Education never ends, Watson. It is a series of lessons, with the greatest for the last."
变化是不可避免的，但进步是一种选择。
The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.
系统的稳定性取决于开环传递函数在复平面上的行为。