"Without some form of market incentive,we believe it will be very hard for them to keep conserving these forests."

VOA: standard.2009.12.17

How can we keep them in school beyond the age of 10 or 12 ? so that they don't join street gangs?

如何让他们在10或12岁后还留在学校2,让他们远离街头帮派？

哈佛公开课 - 幸福课课程节选

and I like to keep up to date with them because it's important that we learn about it.

我喜欢跟上潮流，因为学习潮流很重要。

推荐古老店铺 - SpeakingMax英语口语达人

"We have an electrical barrier in place that we are confident will keep them from moving en masse into the Great Lakes.

VOA: standard.2010.07.20

It doesn't arbitrarily stop anywhere because rhetoric and grammar remain irreducible. We have to keep thinking of them as being uncooperative with each other.

它不会武断地停到任何一个地方,因为修辞和语法是不可削减的，我们必须,一直把它们看成是相互不合作的。

耶鲁公开课 - 文学理论导论课程节选

"I congratulate him for that, and we need to keep up the pressure on them."

VOA: standard.2009.06.23

Before I do that though, let me try and give you an analogy to keep this in mind of why we want to basically build these abstractions and what we need in order to have them work together.

在我们看例子之前请让我打个比方,以便你们能记住我们,为什么要建立这些抽象,以及要使它们协调工作,我们需要做些什么。

麻省理工公开课 - 计算机科学及编程导论课程节选

The fish that,for one reason or another, that found their way past the barrier, we suppressed them and try to take them out of the system to keep them from establishing in Lake Michigan."

VOA: standard.2010.07.20

You might see them on the site and we just keep our operating expenses low so far and by doing that, we've been able to stay cash flow positive for basically the entire existence of the company.

在网站上可以看到,我们一直保持低成本运营，这样可以使得现金流的流入大于流出,自公司创办以来都是这样做的。

斯坦福公开课 - 扎克伯格谈Facebook创业过程课程节选

It's kind of ironic that we put this in the same lecture as we talk about atomic radii, which we also call r, but they're two different r's, so you need to keep them separated in terms of what you're talking about.

有点讽刺的是,我们在同一堂课里还讨论过了原子半径，它也是用，r，表示的，但是它们具有不同的意义，因此大家需要注意区分它们,弄清楚我们讨论的是哪一个。

麻省理工公开课 - 化学原理课程节选

So we know we always want to have our systems in as low an energy as possible, so it makes sense that a bond would happen any time we got a lower energy when we combine two atoms, versus when we keep them separate.

我们知道我们总是希望使我们的系统,处于能量尽可能低的状态，因此就应该有化学键产生,一旦我们合并两个原子之后体系的能量变得更低，相较于分开时。

麻省理工公开课 - 化学原理课程节选