KHOANH ĐÁP ÁN ĐÚNG 11. I never go to Australia. I _________ to Australia yet. A. went B. have been C. will go D. haven’t been 12. I’m _________ Let’s do something. How about going to a movie? A. boring B. bore C. bored D. being bored 13. She knows that he worked really __________ this semester. A. good B. hardly C. better D. hard 14. If someone into the store, smile and say, “May I help you?” A. comes B. came C. come D. should come 15. The death rate would decrease if hygienic conditions improved. A. was B. is C. were D. had been 16. Air pollution has many effects_________ the environment and living organisms. A. in B. of C. for D. on 17. The volcano has erupted approximately once every ten years_________ 1970. A. since B. in C. from D. for 18. This beautiful picture by Mary. A. is drawn B. is drew C. is draw D. is drawing 19. _________ plastic takes so long to break down, it pollutes the land and water. A. Even though B. While C. Since D. Because of 20. If she him, she would be very happy. A. would meet B. will meet C. met D. should meet