A legal system is a system of rules which are valid according to the system's own criteria of validity.

I always thought I wanted to play professionally, and I always knew that to do that I'd have to make a lot of sacrifices.

心理学必须是一门功能的科学，而不仅仅是事实的科学。

The act of writing is an act of courage.

读得越多，越发现自己所知甚少。

“唯一真正永恒的是人类精神。”

The imagination imitates. It is the critical spirit that creates.

The best way to make people happy is to make them laugh.

The great thing about being old is that you don’t have to worry about the future.

森林是地球的肺，我们不要让它窒息。