和平不是免费的,需要不断努力维护。
Peace is not free, it requires constant effort to maintain.
The hardest part of designing a system is deciding what to build.
The moment you think you understand a great work of literature, you're probably wrong.
Science is an adventure into the unknown, every discovery is a reverence for nature.
要这样行动,使得你意志的准则任何时候都能同时被看作一个普遍立法的原则。