【正确答案】
My topic today is "The Car and Air Pollution". In particular, I want firstly to discuss the ways in which the car causes air pollution; and secondly, how we can control or reduce air pollution from the car.
First, then, how does the car cause air pollution? What happens is that the cars internal combustion engine is a kind of chemical factory on a small scale. It uses a mixture of petrol and air, and this mixture explodes and burns, to produce the energy which propels the car. But while this is happening, many complicated chemical reactions are taking place. In particular, part of the petrol-air mixture is not completely burned up, and so the exhaust gases from the engine contain some very dangerous chemicals, such as carbon monoxide, nitrogen oxides, lead and hydrocarbons.
This is the situation, then, and its going to get much worse, unless we do something about it. So let's focus our attention now on ways of controlling or reducing the amount of air pollution caused by the car. I want to mention two major possibilities. First, we can discourage the use of cars. For example, we can put higher taxes on petrol and on cars themselvesespecially the larger ones that use a lot of petrol. Second, we can encourage alternative methods of transport, both between and within urban areas. For instance, we can make train and bus services cheaper and more convenient. And we can build a mass transit system in large cities, particularly an underground railway system such as those in London, New York, Moscow and Tokyo.