每一种化学结合完全且仅仅依赖于两种对立的力量，即正电和负电。
自由是做法律允许的事情的权利。
The test of our progress is not whether we add more to the abundance of those who have much; it is whether we provide enough for those who have too little.
International politics is a ruthless and dangerous business, and it is foolish to expect states to behave according to moral principles.