先阅读短文，然后根据短文内容从方框内所给的单词中选择恰当的词（注意词形变化）填入短文空白处，使短文完整、通顺。一词只用一次，一空限填一词。方框中有两个词是多余的。将能填入空白处的答案写在答题卡上的相应题号后。

The world itself is becoming much smaller by using modern traffic and modern communication. Life today is much       than it was hundreds of years ago, but it has brought new problems. One of the biggest is        . To pollute means to make things dirty. Pollution comes in many ways. We see it, drink it and even hear it.
Man has been polluting the earth. The more people are, the more pollution is. Many years ago, the problem was not so     because there were not so many people. When the land was      up or the river was dirty in a place, men moved to another one. But this is no         true. Man is now slowly pollution the      world.
Air pollution is still the most serious. It’s bad to all living things in the world, but it is not      one kind of pollution. Water pollution       our fish and pollutes our drinking water. Noise pollution makes us become angry more easily.
Many countries are making rules to        pollution. They stop the people from burning coal in houses and factories in the city, and from blowing dirty smoke into the air. The pollution of SO2 is now the most dangerous problem of air pollution. It is caused by heavy traffic. It is certain that if there are fewer people driving, there will be      air pollution.
The earth is our home. We must take care of it. That means       the land, water and air clean.