参考范文：
No air means death. Although we can't see it, there is air round us.So air is everywhere and it gives life to every living thing. Without it we can't live. Bad air makes people ill.We must have fresh air to keep us healthy.In the city there are a great many people and there are too many cars running on the roads. The gas which the cars spread out is full of poison.
Every day we breathe it in and out.Besides so many cars, there are many factories too.From the chimneys of these factories, we get the smoke usually in a black or grey color. This kind of smoke, when it mixes with the air, is dangerous to our health.
It is because smoke contains many small poisonous soils and gases. So inorder to keep healthy we have to go out to the countryside to breathe more fresh air. Or we can go up hills to get more fresh air.
参考译文：
没有空气就意味着死亡。虽然我们看不见它,我们有空气。空气无处不在,它让生活的每一个东西。没有它我们无法生存。糟糕的空气使人生病。我们必须有新鲜空气来保持我们的健康。在城市里有许多人,有太多的汽车在道路上运行。的天然气汽车展开充满了毒药。
我们每天都呼吸它。除了这么多汽车,也有许多工厂。从这些工厂的烟囱,我们得到烟通常在黑色或灰色的颜色。这种烟,当它与空气混合,对我们的健康是很危险的。
这是因为烟包含许多小有毒土壤和气体。所以为了保持健康我们必须去乡下呼吸更多的新鲜空气。或者我们可以得到更多的新鲜空气。