Often visible as smog, ozone is formed in the atmosphere from hydrocarbons and nitrogen oxides, two major pollutants emitted by automobiles, react with sunlight.
显示答案
正确答案: B
- KMF解析
- 网友解析
题目基本信息
- 所属科目:语法SC
- 题目来源1:OG12-84
- 题目来源2:OG15-88
- 正确率: 70%
- 难度: 易