We don't inherit the earth from our ancestors; we borrow it from our children.
领导力是关于愿景和责任，而不是权力。
The young do not know enough to be prudent, and therefore they attempt the impossible – and achieve it, generation after generation.
学习数学的唯一方法就是做数学。
实现明天的唯一限制是我们今天的疑虑。