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Question

 

 

      Everyone wants to reduce pollution. But pollution problem is ______(1) complicated as it is serious. It is complicated ______(2) much pollution is caused by things that benefit people. For example, exhaust ______(3) automobiles causes a large percentage of all air pollution. But automobiles ______ (4) transportation for millions of people. Factories discharge much of the material ______(5) pollutes the air and water, but factories give employment to a large ______(6) of people. Too much fertilizer or pesticide can ruin soil, but fertilizers and pesticide ______ (7) important aids to the growing of crops. Thus, to end ______ (8) greatly reduces pollution immediately, people would have to ______ (9) using many things that benefit them. Most people do not want to do that, of course. But pollution can ______ (10) gradually reduced in several ways.