The greatest obstacle to being heroic is the doubt whether one may not be going to prove one's self a fool; the truest heroism is to resist the doubt; and the profoundest wisdom, to know when it ought to be resisted, and when to be obeyed.

数学中最重要的技能是清晰思考的能力。

我们所认识的最美丽的人是那些经历过失败、痛苦、挣扎、失落，并找到了走出深渊之路的人。