You can't direct a film unless you know what the end is going to be.
Every problem in mathematics is a puzzle waiting to be solved, and the joy is in the solving.
你能写出真相的唯一方法就是假设你写下的东西永远不会被读到。
核心技术是买不来的,必须靠自己研发。
What we learn from history is that people don't learn from history.