清洁的空气对于健康是至关重要的。如果空气中含有杂质，这些杂质就有可能被我们的身体吸收，使人生病。我们需要清洁的空气，但不幸的是，目前普遍存在着空气污染，尤其是在城市里。城市里有许多食品厂、服装厂和制造其他东西的工厂。每天这些工厂把千百万吨的烟灰排放到空气中。工厂产生的东西过一个时期就会损坏，然后就作为垃圾扔掉。我们烧掉许多垃圾，烟灰就增多了。还有工厂生产的汽车，一旦出厂在街上行驶，将会吸进空气，排出有毒气体，并增加空气中的烟尘。
世界上没有任何一个地方可以彻底摆脱空气污染，我们必须采取措施来控制空气污染。现在越来越多的人正在认识到清洁空气的重要性。学校开设了关于污染问题的课程。企业开始帮着净化空气，他们安装了特别的设备来清除自己排放的烟雾。科学家和发明家正在努力开发更清洁的汽车和火车引擎。
或许，人们在城市里能呼吸新鲜空气的日子终将到来。
【参考译文】Clean air is vital to good health. If the air contains impurities, they may be absorbed by our bodies and make us ill. We need clean air, but unfortunately, air pollution is generally present, especially in cities. There are many food factories, garment factories and factories for making other products in cities. Every day these factories discharge million tons of smoke and soot into the air. Things made in factories wear out after a while and then are thrown away as trash. We burn a lot of trash, which produces more smoke and soot. And factory cars, once out of the factory on the street, will suck in air, emit toxic gases, and add to the air soot.
No area in the world can completely be free of air pollution. We must take measures to control it. Now more and more people are realizing the importance of clean air. Schools offers courses on pollution. Industries begin to help clean up, by installing equipment to clean up their smoke. Scientists and inventors are making efforts to develop cleaner automobiles and the engine of train.
Perhaps the day when people are able to breathe fresh air in cities will come at last.
