交换、交易和互换的倾向普遍存在于所有人之中，而在其他动物种族中找不到。
The propensity to truck， barter， and exchange one thing for another is common to all men， and to be found in no other race of animals.
The goal of synthesis should be to make molecules as easily as possible, not just possible.
Hard work and perseverance are the keys to overcoming any challenge.
The highest goal of art is to create harmony between man and his environment.
To feed the world, we must first understand it.