正确答案：
Cars and Air Pollution Cars are indispensable in modern society. However, too many cars have created a lot of serious problems. Besides traffic congestion, accidents and fast fuel consumption, cars are responsible for a good part of air pollution in big cities. All the time, they are pumping a huge amount of waste gases into the atmosphere. These gases are very harmful, causing disease and even death. Last winter, car fumes formed heavy smog over Beijing, making the sky gloomy for weeks and doing harm to people’s health.
One possible solution to the problem is to develop clean cars and clean fuels. In Beijing some of the buses have begun to run on natural gas, which does not give off as much carbon dioxide as the petrol. In Tsinghua University, campus buses are driven by electricity. But it may take decades for the new models of clean cars and clean fuels to completely replace the traditional ones.
Another solution is to improve modern public transportation systems and restrict the use of private cars. If the public transportation system is efficient and convenient enough, most people will choose means of public transportation over private cars. And the total number of cars in big cities will be reduced greatly.
On the whole, the problem of air pollution caused by cars can only be solved by the co-efforts from the government and the public and with the help of science and technology.
解析：
本篇作文同样属于问题解决型，作文第一段首先肯定了汽车在现代生活中占据着不可替代的位置，接着提出汽车过多排放出大量尾气，对环境造成的严重影响；第二、三段提出了可能的解决办法，即开发清洁能源和提高交通系统，减少私家车的数量；最后一段强调汽车所造成的空气污染问题需要政府和公众联合的努力。
【闪光词汇】
indispensable adj. 不可缺少的；绝对必要的
traffic congestion交通拥堵；信号拥堵
co-effort共同努力
