In mathematics, truth is always relative to the system you're working in.
人们为了保护自己不受伤害,会伤害他人。
永远不要停止学习,因为生活永远不会停止教导。
有时候最有力的时刻是那些未说出口的时刻。
The only way to learn mathematics is to do mathematics.
The only fence against the world is a thorough knowledge of it.