凡是大国之所以不攻打小国的，必定是由于这个小国粮食充足，城郭修筑坚固，上下和谐一心。 

There's not a liberal America and a conservative America - there's the United States of America.

建筑师必须是一位科学家。

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

【译文】将知识默记在心，学习时，不感到满足，教人时，不感到倦怠，这三方面我做到了哪些呢？