过去是一张地图，显示我们曾去过哪里。

Combinatorics is like the art of counting without actually counting.

Everyone is shy. Other people are waiting for you to introduce yourself to them， they are waiting for you to send them an email， they are waiting for you to ask them on a date. Go ahead.

We cannot know the cause, and therefore the effect, by reason alone.

The world is full of stories, but the stories are all one.

心灵是一个连续的事件流。