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.

【解释】脑力劳动者统治人，体力劳动者被人统治；被统治者养活别人，统治者靠别人养活，这是通行天下的原则。

"In the end, we will remember not the words of our enemies, but the silence of our friends."