There is not a simple answer. It depends on the subject and level of students,of course.

VOA: special.2009.12.17

Aristotle, in his Politics of course, tells us the most on this subject and often he is our source of information.

亚里士多德,在他的《政治学》中,告诉我们很多有关这个主题的知识,他经常也是我们信息的来源

耶鲁公开课 - 古希腊历史简介课程节选

I think it's reasonable for people who are considering the study of a particular subject in a college course to ask why they should.

大家都想将这一科目,作为一门学问做深入的研习,所以这个问题显得很为必要

耶鲁公开课 - 古希腊历史简介课程节选

Custom dictates that I say something about the subject matter of this course at its outset.

习惯使然，在这堂课开始时,我要说一些关于,这个主题的事。

耶鲁公开课 - 政治哲学导论课程节选

I'll talk about who will benefit from the course and a little bit about sort of the detailed subject matter that we'll cover in the course of this semester.

我会谈到何人将从中受益,以及本学期这门课程,涵盖的内容

耶鲁公开课 - 生物医学工程探索课程节选

Now of course, nutrition is the kind of subject that one could spend the whole semester on, could spend--do multiple classes on, because it's a very interesting, fascinating, and complex topic.

当然,要学习营养学这门课程,可能需要整个学期的时间,耗费很多课时,因为这个话题十分有趣,且吸引人,而又一言难尽

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

How can you use cultured cells to do things, and how do engineers build new things out of cultured cells is going to be a subject we talk about throughout the rest of the course and the chapter is listed here.

如何利用这些培养好的细胞,工程师们如何用培养的细胞制造新产品,这是我们接下来的课程要讨论的主题,相关章节都列在这儿了

耶鲁公开课 - 生物医学工程探索课程节选

So one of my purposes of this course is to get you, whether you study Biomedical Engineering after this or not, excited about the subject so that you start thinking about how you could innovate in this area where lots of problems are still left to solve, so I'll see you on Thursday hopefully.

我这门课的目的之一就在于,无论你们继续学习生物医学工程与否,我想激发你们对这门课的兴趣,思考在这个仍旧存在诸多问题的领域中,你们能做出什么样的创新,希望在周四的课程中再见

耶鲁公开课 - 生物医学工程探索课程节选