The earth is our home.We must take care of it.Life today is easier than it was hundreds of years ago，but it brings some new problems.One of the problems is pollution.
   Many years ago，the problem was not so serious because there were not so many people.When there was no land for people to use or the river was not clean in a place，people went to another place.Now there are many kinds of pollution like water pollution，but air pollution is the most serious.What causes（造成）air pollution？First，people burn（燃燒）something bad.Second，the traffic（交通）is heavy.Because many people don't go to work by bike or on foot.They usually drive their cars to work.When they drive，some bad air comes out.
   I think the government（政府）should do something first.People also need to save the earth and it's time to protect（保護(hù)）the environment together.Everybody should play a part in making our earth a better place.
（1）Many years ago，people

B

B

if the environment became worse.
A．cleaned the river
B．moved to another place
C．did nothing
（2）What causes air pollution？

C

C

A．People burn something bad.
B．The traffic is heavy.
C．Both A and B.
（3）What should everyone do？

C

C

A．Everyone should go to work on foot.
B．Everyone should burn things.
C．Everyone should play a role in saving the earth.
（4）This passage is to

C

C

.
A．tell people about water pollution
B．tell people about air pollution
C．a(chǎn)sk people to protect the environment together