Forests are the lungs of our planet; we must treat them with the care they deserve.

The propensity to truck， barter， and exchange one thing for another is common to all men， and to be found in no other race of animals.

抽象的力量使数学能够超越物理现实的限制。

The rich are different from you and me.

In mathematics, the art of proposing a question must be held of higher value than solving it.

天下的一切事物不可以没有标准，做人要有做人的标准，即原则;做事要有做事的标准，即规则;治国要有治国的标准，即法则。不遵循一定的标准而能成事者，自古以来是没有的。

爱国不是选择，而是责任。