有必要尽快建立更多的低排放区。

It's necessary to create more low-emission zones as soon as possible.

youdao

同时我们也计划2012年一月之前在伦敦建立低排放区，卡车等最污染空气的机动车也在规划之内。

We are also proposing to include the dirtiest lorries and vans in the London low emission zone by early January 2012.

youdao

大部分的时间里激光是暗的，产生低强度的光区伴随着偶尔短暂的高强度光的闪烁。

Most of the time the lasers are dark, producing areas of light with low intensities with the occasionally brief but brilliant flashes of high - intensity light.

youdao

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