Open your eyes and see what you can with them before they close forever.
In mathematics, you don't understand things. You just get used to them.
没有目标的利润就像没有催化剂的化学反应,可能发生,但缓慢而低效得令人痛苦。
一棵树的真正价值不在于它的板材体积,而在于它的根系和影响。