以物易物、互通有无的倾向是人类共有的，也是其他动物所没有的。

每晚我上床睡觉，醒来时就更富有。

Your time is limited, so don't waste it living someone else's life.

The most dangerous phrase in the language is, "We've always done it this way."

It is never right to do wrong or to requite wrong with wrong, or when we suffer evil to defend ourselves by doing evil in return.

Never， never， never give in！