迷宫里的老鼠可以自由地去任何地方，只要它待在迷宫里。
A rat in a maze is free to go anywhere, as long as it stays inside the maze.
一个好计划的最大敌人是完美计划的梦想。
The use of a program to prove the 4-color theorem will not change mathematics - it merely demonstrates that the theorem, a challenge for a century, is probably not important to mathematics.
——〈在北京基督教等六教会欢迎会的演说〉，1912年9月5日
I'm not afraid to fall in love. I'm afraid to fall for the wrong person again.