The writer must believe that what he is doing is the most important thing in the world. And he must hold to this illusion even when he knows it is not true.

The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.

城市是社会的一面镜子。

教育学中的实验方法不仅是研究的工具，更是所有教育实践的基本原则。

It is a sad fate for a man to die too well known to everybody else and still unknown to himself.