NO2 is the main source of nitrate aerosols, which form an important fraction of PM2.5 and, in the presence of ultraviolet light, of ozone.

二氧化氮是硝酸盐气溶胶的主要来源，构成PM 2.5和在紫外线下臭氧的主要部分。

youdao

In the west of this region (at the upper edge of the main image) there are light-coloured, irregular protrusions.

在该区域的西侧(主图像中上部边缘)有一些浅色的不规则突起。

youdao

Otherwise, the main drawback is having to sit in front of the light for 30 to 60 minutes in the morning. CET-6, 2005.6.

另外，它最主要的缺点是你得每天花30到60分钟坐在光线前。

youdao

From the off, they grabbed the attention of the tens of thousands of festival-goers in front of the main stage with their sound and light show.

BBC: Muse

The major use of terbium is in compact fluorescent light bulbs (the other main one is in phosphors for TV screens).

FORBES: The EU Wastes 99% of its High Tech Metals

Three other franchise competitions had also been "paused" in light of the West Coast Main Line situation, Mr McLoughlin confirmed.

BBC: UK