根据短文内容，完成下列各题。
The world itself is becoming much smaller by using modern traffic and modern communication means
(通讯设备). Life today is much easier ① it was hundreds of years ago, but it has brought new problems.
One of the biggest is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it,
smell it, drink it and even hear ② it.
Man has been polluting the earth. ③ The more people, the more pollution. Many years ago, the problem was
not so serious because there were not so many people. When the land was used up or the river was dirty in a
place, man moved to another place. But this is no longer true. Man is now slowly polluting the whole world.
Air pollution is still the most serious. It's bad to all living things in the world, but it is not only one kind of
pollution. Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us become angry
more easily.
Many countries are making rules to fight 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 less air pollution.
The earth is our home. We must take care of it. That means keeping the land, water and air clean. And we
must take care of the rise in population at the same time.
1. 在①处空白处填入合适的连词。
2. 选出②处画线单词“it”的意思。
A. water pollution B. air pollution C. noise pollution D. rubbish
3. 把③处画线部分翻译成汉语。
4. Why is air pollution the most serious kind of pollution?
5. What is the pollution of SO2 caused by?
