Man has been polluting the earth. 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, men 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 (法规) to fight pollution. They stop the people from burning coal(煤) 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 (引起)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 keep careful of the rise in pollution at the same time.

1. Our world is becoming much smaller 　　　　 . ?

A . because the earth is being polluted day and night?

B. thanks to science developing?

C. because of the rise in pollution?

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

2. Thousands 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. water pollution　　　　　　　　　　  B. air pollution   

C. noise pollution　　   　　　　　　   D. rubbish

4. Air pollution is the most serious kind of pollution because 　　　　 . ?

A. it’s bad to all living things in the world?

B. it makes much noise?

C. it has made our rivers and lakes dirty?

D. it makes us become angry more easily

5. Which of the following is not true?

A. Many countries are making rules to fight pollution. ?

B. The pollution on the earth grows as fast as the world’s population does. ?

C. From now on, maybe people try to go to work by bus or bike instead of car or motorbike. It is helpful to fight against the problem of SO_2.

D. The problem of pollution is not so serious because there are not so many people.

　　 Factories often make the air in big cities very dirty. Millions of tons of waste and poisonous （有毒）gases（气）are sent into the air with smoke. Oil is burnt in cars, trucks and buses. They produce waste gases almost as harmful as the gases from factories. In big cities during cold winter months, many old people die from the polluted air. In places around big factories, the bad air kills trees and vegetables.

　　 Another kind of polltion is noise. Very loud noises can make people ill, hurt their ears, or even drive them mad（发疯的）. Houses near the airports sometimes have their windows broken by the noise of jet planes（喷气式飞机）passing overhead.

　　 Man is fighting a battle（战争）against pollution. The battle won't be won until everyone knows how serious the danger is, and does something to stop it.

　　阅读理解

In the cold North there is always snow on the ground. Even in summer it is very cold there. Here is the home of the polar bear. He does not mind the cold. He has a coat of thick white fur.

　　The polar bear likes the cold air as much as you like the warm sunlight. He does not fall on the ice because he has long hair on his paws and he walks very softly. He is very good swimmer and can swim a hundred miles form the shore. In the sea the polar bear catches seals for his dinner.

　　He often walks over the ice and looks for a place where there is no ice.

　　He knows that a seal likes to put out its head, so he sits down and watches. When the round head of the seal comes up, the bear jumps at it. He pulls the seal out of the water, kills it and eats it.　　 Sometimes the bear jumps into the water himself and catches a fish.

　　In summer the polar bear also looks for berries. When he is very hungry he eats even the seaweed on the shore.

　　The people who live in the far North hum the polar bear. His meat and fat give them food, his thick skin gives them a warm bed.

　　They also cut it up and make it into coats, hats and gloves.

　　(1)It's very cold ________ in North.

[　　]

　　A． in winter

　　B． in summer

　　C． in spring

　　D． all the year around

　　(2)The polar bear isn't afraid of cold because ________.

[　　]

　　A． he likes cold

　　B． he doesn't like warm

　　C． he has thick fur to defence cold

　　D． he has fire in his body

　　(3)The polar bear ________ for his dinner.

[　　]

　　A． catches seals or fish

　　B． looks for berries or seaweed

　　C． not only catches seals or fish but also looks for berries of seaweed

　　D． only catches seals

　　(4)The polar bear is a good swimmer, so ________.

[　　]

　　A． he often swims in the sea shore

　　B． he lives in the sea

　　C． he often looks for some food in the sea

　　D． he often swims in the river

　　(5)Don't hunt the polar bear because ________.

[　　]

　　A． the polar bear is a useless animal

　　B． it isn't interesting

　　C． the polar bear is a rare animal

　　D． it is too heavy to carry it