Quality is never an accident; it is always the result of intelligent effort.

Natural experiments can provide valuable insights into economic questions.

Materials are the words of architecture.

所以，根基树立不牢的人，不要期望有茂盛的枝叶。 

Be governed not by the tyranny of the urgent but by the elevation of the important.

解释：死亡、生存、惊恐、惧怕等观念都进入不到他的内心中，因而遇到任何事情都不害怕。

如果你认为强悍的人很危险，那就等着看弱者能做什么。