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

If you think about it conceptually, try to figure out, well, I got this board up here, this tapestry, or whatever, where's my melody going to be in the texture: high, middle or low? Michael?

请从概念上来思考它,试着找出,面对这块黑板,或挂毯,或任何东西,我的旋律该在织体的哪个位置,高,中间,还是低,迈克尔你说

耶鲁公开课 - 聆听音乐课程节选