1．Hundreds of years ago，life was 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 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 （被狀物） over a city．This kind of quilt is called smog．
Many countries are making rules to fight pollution．Factories must now clean their water before it is thrown away，and they mustn't let dirty smoke go into the air．
We need to do many other things．We can put waste things in the dustbin and do not throw them on the ground．We can go to work by bus 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 pollution．
36．Hundreds of years ago，life was much harder than it is todaybecauseC．
A．there were not modern machines
B．there was no modern medicine
C．both A and B
D．there were not many people
37．D is the biggest problem in today's life．
A．Water pollution
B．Air pollution
C．Noise pollution
D．Pollution
38．The most serious kind of pollution isB．
A．noise pollution
B．a(chǎn)ir pollution
C．water pollution
D．A，B and C
39．Factories must clean their waterD．
A．before they are thrown away
B．when they are thrown away
C．a(chǎn)fter it is thrown away
D．before it is thrown away
40．From the passage，we know thatD．
A．a(chǎn) few years ago，there was no smog at all
B．today people don't have to talk to each other loudly
C．we can drink water from the polluted rivers and lakes
D．people are making rules in order to （為了）fight pollution．
