The study of mathematics is like air or gravity—it is everywhere, and you can't see it, but you know it's there.

"La única manera de librarse de la tentación es caer en ella."

孤独是清醒的代价。

墨子说：言论如果能够付诸行动的就可以讲；不能够付诸行动的就别多说。言论不能付诸行动的而常讲，这就是卖弄口才了。