Always look at what you have left. Never look at what you have lost.

技术不仅仅是一种工具。它可以赋予学习者以前可能没有的声音。

数学是一种思维方式，而不仅仅是一堆事实。

I’ve learned that sometimes you have to be a little bit brave.

衡量一家公司成功的真正标准是它对人类和地球的影响。

You can't change what's going on around you until you start changing what's going on within you.

数学的本质在于它的自由。