According to the speaker what is the feature of air pollutants?A.Its contents often remai
选择题,
已帮助 人
According to the speaker, what is the feature of air pollutants?
A.Its contents often remain stable.
B.Its definition will change over time.
C.Air pollutants are natural.
D.Air pollutants are man-made.
此题为多项选择题。请帮忙给出正确答案和分析,谢谢!
