1.Clean air is important to good health.If the aircontains impurities,they may be absorbed by ourbodies and make us ill.We need clean air,butunfortunately,air pollution is generally present,especially in cities. 2.Our...1.Clean air is important to good health.If the aircontains impurities,they may be absorbed by ourbodies and make us ill.We need clean air,butunfortunately,air pollution is generally present,especially in cities. 2.Our cities have many factories,which we need tomake food products,clothing and many other things.展开更多
文摘1.Clean air is important to good health.If the aircontains impurities,they may be absorbed by ourbodies and make us ill.We need clean air,butunfortunately,air pollution is generally present,especially in cities. 2.Our cities have many factories,which we need tomake food products,clothing and many other things.
