The only limit is the one you set yourself.
I have now taken a serious task upon myself and I fear a greater one than is in the power of any man to perform.
The universe is not only stranger than we imagine, it is stranger than we can imagine.
Success is not final, failure is not fatal: It is the courage to continue that counts.
学习数学的唯一方法就是做数学。
You can’t lead people if they don’t believe you care about them.
有时候你必须独处才能真正找到自己。
The future of coal is bright if we fight for it.