In mathematics, you don't understand things. You just get used to them.
Twenty years from now, you will be more disappointed by the things you didn’t do than the ones you did.So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover. （注：这句说话被部分人质疑不是由马克·吐温所说的。）
"The world is a mysterious place, and we are all just trying to find our way through it."