解释：先前所使用的，现在或许要抛弃。现在要抛弃的，将来或许会用到。

When I look at the world I'm pessimistic, but when I look at people I am optimistic.

非暴力是人类拥有的最伟大的力量。

My favorite things in life don't cost any money. It's really clear that the most precious resource we all have is time.

所有人的生活里都有一部历史。

追求知识是一场没有终点的旅程，每一次发现都为新的奥秘打开了大门。