Well, a cross-sectional study would mean that you'd get a random group of the population and measure them in 1970 and then take another random group five years later and measure them, but it wouldn't be the same people necessarily, it would be different groups of people.

那么,横断面研究就是,1970年你在人群中随意选择一组人,并记录下相关数据,然后,五年后再随意选择一组人记录数据,但这不需要是同一组人,通常是不同的人

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

In college, there are a variety of people. What do you think about the different groups?

在大学里有各种各样的人。你对不同的人有什么看法？

学习和交际都重要 - SpeakingMax英语口语达人

because that way a lot of different groups can use the same space.

因为这样一来很多不同的团队可以用同一个空间。

学生会馆的实习部门 - SpeakingMax英语口语达人

What I want to talk about here though is a different aspect of how we think about human groups.

但我今天想讲的是,我们对群体的看法的另一个方面。

耶鲁公开课 - 心理学导论课程节选

Literally all over the world, there are different groups.

简直在全世界都有，不同的团体。

求职攻略 - SpeakingMax英语口语达人

We have tissues like the brain which are assembled to do functions that are different from any other groups of cells in the body.

像我们的脑组织,它们的功能,就截然不同于身体其他部分的细胞功能

耶鲁公开课 - 生物医学工程探索课程节选

So how are we to account for the diversification of languages, the spread of different ethnic linguistic groups throughout the lands of the earth if we all come from one common creative moment, one common ancestor?

所以，如果我们都起源于同一个时刻，来源于,同一个祖先，那又要怎样解释语言的多样性，怎样解释,使用不同语言的族群遍布地球上的所有土地,这一现象呢？

耶鲁公开课 - 旧约导论课程节选

" Why do different human groups differ in intelligence?"

为什么不同人群之间会有智力差异“

耶鲁公开课 - 心理学导论课程节选

So, these groups developed different cultures.

两队形成了不同的文化。

耶鲁公开课 - 心理学导论课程节选