ét ô ét giúp với cần gấp =)))

III. Choose the best answer a, b, c or d to complete the sentence. 1. Air pollution has many effects the environment and living organisms. C. for A. in В. of D. on 2. The volcano has erupted approximately once every ten years В. in 1970. A. since C. from D. for 3. After a severe storm, ...