Who knows? And that's a different type of search. I'm trying to urge the SETI community to change their tactics a bit."

VOA: standard.2010.04.16

Maybe somebody who knows Citizen Kane and would like to have a grade for the first 50 pages.

也许比较清楚了解的同学可以做,需要先读前50页的内容。

麻省理工公开课 - 电影哲学课程节选

I'm going to live here for, who knows how long. Quite a long time.

我打算定居在这儿，不知道多久。会是相当长一段时间。

追忆艾米 - SpeakingMax英语口语达人

"So if you get an audience of 10 million people there's a lot of 'don't knows' who watch you and what you say, what you do,in those 90 minutes could be quite decisive."

VOA: standard.2010.04.23

Anybody whose read a basic finance text, as a matter of fact, I think anybody who thinks about investments in a common sense fashion knows that diversification is an important fundamental tenet of portfolio management.

事实上,任何一个读过金融基础教材的人,任何一个,以正常思维来考虑投资问题的人,都知道分散投资是投资管理的,一条重要的基本原则

耶鲁公开课 - 金融市场课程节选

I usually ask for advice from a friend who knows those materials very well.

我都会向一个精通电子产品的朋友请教。

What kind of 课堂 - SpeakingMax英语口语达人

That is, if you plot the relationships between people We can take each person in this room, find everybody you know and who knows you and draw a line, but if we were to do this you wouldn't find an even mesh of wires.

也就是说如果要划出人们之间的关系,例如这个教室里的人，把互相认识的人用线划出来，如果我们这样做,得到的结果不是一个分布均匀的网状图。

耶鲁公开课 - 心理学导论课程节选