The only source of knowledge is experience.

A man takes a rocket ship into the stars, and all I got is this broken guitar.

当今煤炭行业的领导力意味着在经济需求和环境责任之间找到微妙的平衡。

States are rational actors that seek to maximize their relative power in order to ensure their survival in a competitive international system.

美好的生活不是没有悲伤，而是在痛苦中能促进我们成长的生活。

The concept of law is a complex one, and it is not easy to define.