If you want to understand a system, try changing it.

The farmer is the only man in our economy who buys everything at retail, sells everything at wholesale, and pays the freight both ways.

挑战是伪装的机遇；拥抱它们并变得更强大。

"Every saint has a past, and every sinner has a future."

物理学的美丽在于它能够揭示宇宙表面复杂性之下的深刻简单性。