Passage 3-|||-People all over the world today are beginning to hear and learn more and more about the-|||-problem of pollution.Pollution is caused either by man`s release of completely new and often-|||-artificial(人造的)substances into the environment,or by releasing greatly increased amounts of-|||-a natural substance(物质),such as oil from oil tankers into the sea.-|||-Whatever its underlying reasons,there is no doubt that much of the pollution caused could-|||-be controlled if only companies, individua and governments would make more efforts.In the-|||-home there is an obvious need to control litter and waste.Food comes wrapped up there or four-|||-times in packages that all have to be disposed of;drinks are increasingly sold in bottles or tins-|||-which cannot be reused.This not only causes a litter problem,but also is a great waste of-|||-resources,in terms of glass,metal and paper.Advertising has helped this process by persuading-|||-many of us not only to buy thing we neither want nor need,but also to throw away much of what-|||-we do buy.Pollution and waste combine to be a problem everyone can help to solve by cutting-|||-out unnecessary buying,excess use and careless disposal(处理)of the products we use in our-|||-daily lives.-|||-16.The main cause of pollution is __ .-|||-A.the release of artificial or natural substances into the environment-|||-B.the production of new industrial goods-|||-C.increased amounts of a natural substance-|||-D.our ever-increasing population-|||-17.Much of the pollution could be controlled if only __ _-|||-A.people would pay more attention to the problem-|||-B.governments would take effective measures-|||-C.all sides concerned would make more efforts-|||-D.farmers would use less artificial fertilizers-|||-18.Food packages,bottles and tins for drinks can cause __ .-|||-A.air and water pollution B.both a litter problem and a waste of resources-|||-C.to pay for the service D.to produce the receipt-|||-19.Which of the following can not help solving the problem of pollution?-|||-A.Cutting out unnecessary buying B.Eating less-|||-C.Reduce excess use D.Carefully dispose our daily products.-|||-20.What does the underlined word "litter" mean in paragraph 2 ?-|||-A.not many B.serious problem-|||-C.bits of waste things D.industrial pollution