经济理论提供工具，但现实世界的测试会完善它们。

So happiness is the most popular word we have heard through the past two years. Happiness is not only related to personal experiences and personal values, but also, it's about the environment.

可以同他交谈却没有交谈，这是错过了人才。不可以同他交谈却要同他交谈，这是白费口舌。聪明的人既不错过人才，又不浪费语言。

A good detective knows that every answer leads to another question.