I will hazard a prediction. When you are 80 years old， and in a quiet moment of reflection narrating for only yourself the most personal version of your life story， the telling that will be most compact and meaningful will be the series of choices you have made. In the end， we are our choices. Build yourself a great story.

唯一的限制是你自己设定的限制。

The beauty of mathematics is that it is eternal, it doesn't change.

过去是一个陌生的国度；那里的人行事不同。