A good mathematician is one who can see analogies between theorems; a great mathematician is one who can see analogies between analogies.
一个好的数学家是能看到定理之间类比的人；一个伟大的数学家是能看到类比之间的类比的人。
Life is a journey, and every experience is a lesson.
It is much easier to change how you think by changing your behavior， than it is to change your behavior by changing how you think. Act out the change you seek.
主要的义务规则是那些要求或禁止某些行为的规则。
在化学工业中，安全不是一个部门，而是一种文化。