Every setback is a setup for a comeback.

The past is always there, and it's always different every time you look at it.

学习数学的最好方法就是去做数学。

Making something variable is easy. Controlling duration of constancy is the trick.

没有分析，就没有合成；没有合成，也就没有分析。

Never be afraid to take risks. The biggest rewards often come from the biggest risks.