The world itself is becoming much smaller by using modem traffic and modem communication means(通讯设备)．Life today is much easier than it was hundreds of years ago, but it has brought new problems．One of the biggest problems is pollution．To pollute means to make things dirty．Pollution comes in many ways．We see it, smell it, drink it and even hear it．

Man has polluted the earth．The more people, the more pollution．

Air pollution is still the most serious．It’s bad for all living things in the world, but it is not the only kind of pollution．Water pollution kills fish and pollutes our drinking water．Noise pollution makes us angry more easily．

Many countries are making rules to fight pollution．

They stop people from burning coal in houses and factories and from putting dirty smoke into the air．Pollution by SO₂ is now the most dangerous kind of air pollution．It is caused by heavy traffic．We are sure that if there are fewer people driving, there will be less air pollution．

The earth is our home．We must take care of it．

1．        , our world is becoming much smaller．

A．Thanks to the science development

B．Because of the rise in pollution

C．Because the earth is being polluted day and night

D．Because the earth is blown away by the wind every year

2．Hundreds of years ago, life was         it is today．

A．much easier than                                       B．as easy as

C．as hard as                                              D．much harder than

3．Pollution comes in many ways．We can even hear it．Here “it” means        ．

A．rubbish              B．air pollution          C．water pollution      D．noise pollution

4．Which of the following is NOT TRUE?

A．Many countries are making rules to fight pollution．

B．The problem of pollution is not so serious because there are not so many people living on the earth．

C．The pollution of the earth grows as fast as the world population does．

    D．If people could go to work by bus or bike instead of car or motorbike, it would be helpful in fighting against the problem of SO₂．

5．        is the most serious among the pollution．

A．Water pollution        B．Noise pollution      C．Air pollution          D．Light pollution

The world is not only hungry but also thirsty for water. This may seem strange to you, since nearly 70% of the earth’s surface is covered with water. But about 97% of that is sea water or salt water. Man can only drink and use the other 3% of fresh water from rivers, lakes, underground and so on. And we can not even use all of that because some of it has been made dirty.
Earth Day is April 22. But on all other days, we must also remember how important water is. The water that we use is the most important natural resource on the earth. Today we face serious water problems. One of them is water pollution. All kinds of things from cars, factories, farms and homes make our rivers, lakes and oceans dirty. Polluted water is very bad for people to drink. And dirty water is bad for fish, too.
How do cars and factories make our water dirty? First they pollute the air. Then when it rains, the rain water makes our drinking water dirty. Dirty rain, called acid rain is also bad for plants, animals and buildings. Scientists say that in 30 years, more than half of the people in the world won’t have enough clean water. We have to learn how to stop wasting water. One of the first steps is to develop ways of reusing it. Today in most large cities, water is used only once and then sent out into a sewer system (下水道). From there it returns to the sea or goes underground.
But even though every large city reused its water, we would still not have enough. So we should make use of sea water by removing the salt in it. If we can take these steps, fresh water won’t be used up.
【小题1】The world is thirsty for water because _______.