No. 2, we believe that young people have to be a key part of building that ethos One of the reasons for that is purely demographic.

其次，我们认为青年人,必须成为建立该社会风气的主力,其中的一个原因,纯粹是从人口统计学来考虑的。

普林斯顿公开课 - 人性课程节选

All of those slave societies had a population of slaves that was from one-quarter to one-half, and sometimes more, of the total population.

这些奴隶社会的奴隶人口都占总人口,的三分之一到一半,有时甚至更多

耶鲁公开课 - 美国内战与重建课程节选

What is inescapable is farmers are a sociological category of people, different from non-farmers in all kinds of critical ways, and it is just an example of how this whole business has disappeared.

不可否认的是,农业人口是一种社会学对人口的分类,和非农业人口是完全不同的,这只不过是,整个产业走向消亡的一个例子罢了

耶鲁公开课 - 古希腊历史简介课程节选

Now, in any society changing this much, this fast, doubling its own population--doubling--in twenty-five years.

现在,在任何变化如此巨大的社会,如此迅速地,在二十五年内,人口增至两倍

耶鲁公开课 - 美国内战与重建课程节选