The earth is our home and we must take good care of it.That

The earth is our home and we must take good care of it.That is to say we must ( )the land,air and water clean.But man 9 )a lot of pollution on the earth since he first made a fire ,washed his clothes in the river and threw waste or ( )on the ground.Many years ago ,pollution was not so serious( )there were not so many people.
There was though( )air,land and water.When the land or the river was dirty in one place,man moved to ( )place.Man now ,( ),is slowly polluting the whole world and there is neither enough clean air,nor clean land nor clean water .The more people there are in one place ,( )environment they maybe have.
Perhaps you ( )it is endless for people to produce pollution.( ),we are glad to tell you that people have come to know the danger of pollution and more and more people are working hard to protect our earth.
1.A.have B.take C.watch D.keep
2.A.produced B.has produced
C.is producing D.will produce
3.A.rubbish B.dirty C.something useful D.food
4.A.so B.if C.because D.but
5.A.clean B.clear C.dirty D.drinking
6.A.other B.the other C.another D.others
7.A.although B.however
C.too D.but
8.A.the worst B.the worse c.the bad D.worse
9.A.are gald B.are pleased C.afraid D.are afraid
10.A.Quickly B.Especially
C.Luckily D.Angrily