我曾把许多东西握在手中，但都失去了；但无论我把什么放在上帝的手中，我仍然拥有它。
I have held many things in my hands, and I have lost them all; but whatever I have placed in God's hands, that I still possess.
数学的本质不仅在于解决问题，还在于提出正确的问题。
你唯一的限制就是你相信的限制。
The young do not know enough to be prudent, and therefore they attempt the impossible – and achieve it, generation after generation.
元素可以分为具有相似性质的组。