Read the following passage and mark th...

Câu hỏi: Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 55 to 64

A. The economic impact of air pollution. 

B. The effects of compounds added to the atmosphere

C. What constitutes an air pollutant 

D. How much harm air pollutants can cause.