The essence of mathematics is not to make simple things complicated, but to make complicated things simple.

States are rational actors that seek to maximize their power and security in an anarchic international system.

友谊不在于你认识谁最久，而在于谁走进你的生活说"我在这里支持你"，并且证明了这一点。

The most dangerous phrase in business is 'We've always done it this way.'

老虎间，还可以相互靠近，人即使很熟悉，还是不能真正亲近；在你面前议论别人是非的人，其实这种人就是一个搬弄是非的人。