My bid concern is that you have this huge group of people on the planet 2 young people between ages of say 12 and 19 or 21 or 22 all asking the question: Who am I?

我最关注的是,我们在世界上拥有如此巨大的一个群体,即年龄介于12到19岁，或者21，22岁的青年人2,都在问一个问题：,我是谁？

普林斯顿公开课 - 人性课程节选

The key line in the society of the Dark Ages appears to be certainly not between monarchy and everybody else, but between nobility and commoners.

黑暗时代的社会中,最重要的主线,显然不是君主阶级和平民们之间,而是贵族和平民之间

耶鲁公开课 - 古希腊历史简介课程节选