数学中最深刻的思想往往源于最简单的观察。

Stray birds of summer come to my window to sing and fly away。 And yellow leaves of autumn， which have no songs， flutter and fall there with a sigh。

对少数人有用的东西对多数人不起作用。

AdS/CFT对应是理解量子引力的有力工具。