The invention of the cotton gin was the result of necessity and observation.
如果你不能安全地开采它,你根本不应该开采它。
释义:水一旦泼出去,就收不回来,后悔也来不及。
It is the greatest happiness of the greatest number that is the measure of right and wrong.
强大的品牌建立在透明和诚信之上。