Absorption is just the opposite of emission, so instead of starting at a high energy level and dropping down, when we absorb light we start low and we absorb energy to bring ourselves up to an n final that's higher.

吸收就是发射的逆过程,与从一个高能量到低能量不同，当吸收光时，我们从低能量开始,吸收能量到一个更高的能量。

麻省理工公开课 - 化学原理课程节选

And not be too critical or expect that you should be at a very high level when you're just beginning.

不要太挑剔，也不要奢望自己刚开始的时候就可以达到很高的水平。

学外语的时候 - SpeakingMax英语口语达人

So, for example, we have this average level, and then it can go high where we have the peak, or it can go very low. We can also discuss sound waves, so again it's just the periodic variation of some property -- in this case we're talking about density, so we have high density areas and low density areas.

例如这是平均位置，在峰的位置水位高，在谷水位低，我们也可以,讨论声波它也是某种,量的周期变化，在这里我们,讨论的是密度,我们有高密度区和低密度区。

麻省理工公开课 - 化学原理课程节选

We're going to talk in some detail, not a very high level of detail, but in some detail about how this communication takes place between cells and how the information is passed down one of these cells today.

我们还要讨论些细节问题,但不是太深,今天只讲细胞间通讯的发生原理,和信息怎样从一个细胞传递到另一个细胞

耶鲁公开课 - 生物医学工程探索课程节选