平凡与非凡之间的区别就在于那一点点额外的努力。

To teach mathematics is to inspire the next generation of thinkers and problem solvers.

The knowledge that you have emerged wiser and stronger from setbacks means that you are, ever after, secure in your ability to survive. You will never truly know yourself, or the strength of your relationships, until both have been tested by adversity. Such knowledge is a true gift, for all that it is painfully won, and it has been worth more than any qualification I ever earned.

"In observational studies, we often have to rely on assumptions that are not directly testable."