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.
I have a dream, and that dream is worth every sacrifice I make.
每个圣人都有过去,每个罪人都有未来。
Lightness is not just physical, but also psychological.
Out of my own great woe I make my little songs.