Bài I:
Everyone wants to reduce pollution. But the pollution problem is as complicated as it's serious. It's 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 the automobile provides transportation for millions of people. Factories discharge much of the material that pollutes air and water, but factories give employment to a large number of people.  

Thus, to end or greatly reduce pollution immediately, people would have to stop using many things thatbenefit them. Most people do not want to do that, of course. But pollution can be gradually reduced in several ways. scientists and engineers can work to find ways to lessen the amount of pollution that such things as automobiles and factories cause. Goverment can pass and enforce laws that require businesses and individuals to stop, or cut down on certain polluting activities.