劳动经济学从根本上讲是理解人们的选择和约束。

A society grows great when old men plant trees whose shade they know they shall never sit in.

世界是一个舞台，但我们大多数人只是舞台工作人员。

If you don't know where you are going, any road will get you there.

向清洁能源的转型是不可逆转的。