Everyone wants to reduce pollution. But pollution problem is as complicated as it is serious. It is complicated because much pollution is caused by things that benefit people. For example, exhaust from automobiles causes a large percentage of all air pollution. But automobiles provide transportation for millions of people. Factories discharge much of the material which pollutes the air and water, but factories give jobs to a large number of people. Too much fertilizer or pesticide can ruin soil, but fertilizers and pesticide are important aids to the growing of crops. Thus, to end or reduce pollution immediately, people would have to stop using many things that benefit them. Most people do not want to do that, of course. But pollution can be gradually reduced in several ways. 28. What problem is complicated as it is serious? 1 điểm A. pesticide B. crop C. pollution D. factory 29. Exhaust from automobiles causes _______. 1 điểm A. air pollution B. noise pollution C. water pollution D. light pollution 30. Discharge from factories pollutes _______. 1 điểm A. fertilizer and crop B. factory and transportation C. soil and crop D. air and water 31. What does the word “pesticide” mean? 1 điểm A. a metal container B. chemical used for killing pests C. any substance like air D. a cold drink 32. The word “several” can best be replaced by ________. 1 điểm A. some B. any C. few D. little