With the (61)___ (develop) of industry,air pollution is getting more and more serious.In Beijing,many people suffer different kinds of illnesses because (62)___ air pollution.
Air pollution is caused by the following (63)___:about half of the problem is caused by vehicles.There are more and more cars,buses on the roads,and they give off (64)___ (poison) gases.25% of air pollution is caused by factories.Another factor is the smokers.Smoking not only does harm
to their health (65)___ to others.(66)___ these,about 10% of air pollution is caused by other reasons.
We should take some measures to fight (67)___ pollution.New fuel can be used to take (68)___ place of gas.We can plant more trees.If everybody realizes the (69)___ (important) of environment and does something to stop pollution,the problem will (70)___ (solve).