我不必那么害怕告别，因为告别不一定是永远的。

世界的历史是各民族交融的历史。

The past does not equal the future.

Persistence is the key to unlocking the mysteries of medicine.

所有的变化，即使是最渴望的，也带着忧郁；因为我们留下的是一部分的自己；我们必须告别一种生活，才能进入另一种。

农业的成功源于对土地和耕种者的理解。

Welcome, O life! I go to encounter for the millionth time the reality of experience and to forge in the smithy of my soul the uncreated conscience of my race.

The opening up of new markets, foreign or domestic, and the organizational development from the craft shop and factory to such concerns as U.S. Steel illustrate the same process of industrial mutation—if I may use that biological term—that incessantly revolutionizes the economic structure from within, incessantly destroying the old one, incessantly creating a new one.