数学中最深刻的问题往往源于最简单的问题。
The deepest problems in mathematics often arise from the simplest questions.
Hope is not an emotion, but a choice.
The only way to deal with an unfree world is to become so absolutely free that your very existence is an act of rebellion.
你必须承担个人责任。你无法改变环境、季节或风向,但你可以改变自己。