I don't count my sit-ups. I only start counting when it starts hurting.

谦虚：向苏格拉底和耶稣学习。

The existence of the natural world is the same kind of fact as the existence of any proposition.

数学不是观赏性运动，你必须参与其中才能理解。

在热量下降过程中，动力显然随冷热物体之间的温差增大而增加。