To accurately assess the level of second-hand smoke exposure, researchers tested for cotinine, which is produced when nicotine is metabolized.

VOA: standard.2010.06.15

But then it will also be taught at the second level, which is for every paper that you'll read, every paper that you'll write, you'll always be thinking, "Ok, how can I take these ideas and apply them to my life?

而教学内容的另一部分，你们读每一篇论文，写每一篇论文时，都需要思考，如何把这些理念运用到生活中去？

哈佛公开课 - 幸福课课程节选

At this point, we have no other choice but to double up before going to the next energy level, 2px so we'll put a second one in the 2 p x.

在这点上我们没有其他选择,而只有双倍填充,在到下一个能级之前，所以我们放入第二个电子至。

麻省理工公开课 - 化学原理课程节选

" Any of the crises we have seen since the second World War, you have not had this level of international cooperation."

VOA: standard.2009.04.01

And as I will explain in a second there are many reasons why this sense hasn't really been elucidated at the molecular level.

难以真正从分子学的角度阐明,这种感官的原因是多方面的,有关这一点,稍后我会另行解释。

斯坦福公开课 - 7个颠覆你思想的演讲课程节选

So, that, for me, was kind of the first connection that what went, "Woah, wait a second, I want to be thinking about these molecules all the way down to the level of individual atoms."

接下来我遇到的一个问题,哇哦，等等，让我想想，是我在学习,有机化学的时候“

麻省理工公开课 - 化学原理课程节选