The world is everything that is the case.

The only thing that is constant is change.

住酒店时，把所有的东西都放在显眼的地方，不要放在抽屉里，全部集中到一个地方。这样你就不会落下任何东西。如果你需要把充电器之类的东西放在一边，在它旁边放几件其他的大件物品，你落下三样东西的可能性比落下一件要小很多。

I was working at a financial firm in New York City with a bunch of very smart people， and I had a brilliant boss that I much admired. I went to my boss and told him I wanted to start a company selling books on the Internet. He took me on a long walk in Central Park， listened carefully to me， and finally said， "That sounds like a really good idea， but it would be an even better idea for someone who didn't already have a good job." That logic made some sense to me， and he convinced me to think about it for 48 hours before making a final decision. Seen in that light， it really was a difficult choice， but ultimately， I decided I had to give it a shot. I didn't think I'd regret trying and failing. And I suspected I would always be haunted by a decision to not try at all. After much consideration， I took the less safe path to follow my passion， and I'm proud of that choice.

Investors should avoid trying to time the market; it's a losing strategy.

Profitability and purpose are not mutually exclusive.

To do mathematics is to explore an infinite landscape of ideas.

The best way to learn computer science is to do computer science.