"The only way to learn mathematics is to do mathematics."

We're not going to run out of ammunition.

Quality is never an accident; it is always the result of intelligent effort.

行动是正确的，因为它们倾向于促进幸福；错误是因为它们倾向于产生与幸福相反的结果。

Sustainability isn't an option; it's our responsibility to the next generation.

The greatest enemy of a good plan is the dream of a perfect plan.