你必须是自己幸福的最好判断者。

"The great secret that all old people share is that you really haven't changed in seventy or eighty years. Your body changes, but you don't change at all. And that, of course, causes great confusion."

人类的历史在很大程度上是与环境斗争的历史。

物理定律在宇宙中无处不在，这是一个深刻的真理，将我们所有人联系在一起。

Your most unhappy customers are your greatest source of learning.