生活，我们在世上是为了对它尽力增益，而不是从中竭力索取。
A mathematician's intuition is as important as rigorous proof.
过去从未死去，它甚至还未过去。
A hundred times every day I remind myself that my inner and outer life are based on the labors of other men, living and dead, and that I must exert myself in order to give in the same measure as I have received and am still receiving...