7．A．bad　　　　 B．safe　　　 　　C．hard　　　　 D．possible

6．A．flew　　　　 B．ran　　　　　 C．moved　　　 D．arrived

5．A．if　　　　　 B．because　　　 C．until　　　 　　D．when

4．A．better　 　　　B．more　　　　 　C．fewer　　　 D．stranger

3．A．smell　　　　 B．touch　　　　 C．dream　　　 D．want

2．A．difficulties 　　B．business　　　 C．jobs　　　　 D．problems

1．A．Flight　　　　 B．Sleeping　　　 C．Life　　　　 D．Meeting

15. A. When　　　　 B. Since　　　　　　　 C. If　　　　　　 D. As

D

The world itself is becoming much smaller by using modern traffic and modern communication means(通讯设备). 　 　1　 　today is much easier than it was hundreds of years ago，but it has brought new　　 　2　 　．One of the biggest is pollution．To pollute means to make things dirty．Pollution comes in many ways．We see it，　　 3　 　　it，drink it and even hear it．

Man has been polluting the earth．The　　 　4 　　people，the more pollution．Many years ago，the pollution was not so serious　　 5　 　　there were not so many people．When the land was used up or the river was dirty in one place，man　　　 6 　　　to another place．But this is no longer true．

Man is now slowly polluting the whole world．

Air pollution is now the most serious．It’s　　 　7　 　　for all living things in the world，but it is not the only one kind of pollution．Water pollution　　 　8 　　our fish and pollutes our drinking water．Noise pollution makes us　become　 9　　more easily．

Many countries are making rules to fight pollution．They　　 10　 　　people from burning coal(煤)in houses and factories in the city，and from putting dirty　　 　11　 　　into the air．

Pollution by SO₂ is now the most　　 12　 　　kind of air pollution．It is caused by heavy traffic．It is true that if there are fewer people　　 13　 　，there will be less air pollution．

The earth is our home．We must take care of it．That means　　 14 　the land，water and air clean．And we must take care of the　　 15　 　　in pollution at the same time．

14. A. and　　　　　 B. but　　　　　　　　 C. while　　　　　 D. as

13. A. just　　　　　 B. just now　　 　　　　C. right now　　　 D. now