题目内容：

Pollution

Hundreds of years ago，life was much harder than it is today.People didn't have modern machines.There was no modern medicine，either.

Life today has brought new problems.One of the biggest is pollution.Water pollution has made our rivers and lakes dirty.It kills our fish and pollutes our drinking water.Noise pollution makes us talk louder and become angry more easily.Air pollution is the most serious kind of pollution.It's bad to all living things in the world.

Cars，planes and factories all pollute our air every day.Sometimes the polluted air is so thick that it is like a quilt over a city.This kind of quilt is called haze (雾霾)．

Many countries are making rules to fight against pollution.Factories must now clean their water before it is thrown away，and they mustn't blow dirty smoke into the air.

We need to do many other things.We can put waste things in the dustbin and not throw it on the ground.We can go to work by bus or with our friends in the same car.If there are fewer people driving，there will be less pollution.

Rules are not enough.Every person must help to fight against pollution.

1.Hundreds of years ago，life was much harder than it is today because________.

A. there were not any modern machines

B. there was no modern medicine

C. both A and B

D. there were not many people

2.What is the biggest problem in today's life?

A. Water pollution.    B. Air pollution.

C. Noise.    D. Pollution.

3.The most serious kind of pollution is________.

A. noise pollution,    B. air pollution

C. water pollution,    D. A，B and C

4.Factories must clean their water________.

A. before they are thrown away

B. when they are thrown away

C. after it is thrown away

D. before it is thrown away

5.From the passage we know that________.

A. a few years ago，there was no haze at all

B. today people don't have to talk to each other in a loud voice

C. we can drink water from the polluted rivers and lakes

D. people are making rules in order to fight against pollution