你永远不知道你的坏运气为你避免了什么更糟的运气。
You never know what worse luck your bad luck has saved you from.
The magic, the wonder, the mystery and the innocence of a child's heart are the seeds of creativity that will heal the world.
The best time to plant a tree was 20 years ago. The second-best time is now.
我不认为每个人都应该成为数学家，但我确实相信许多学生没有给数学一个真正的机会。