(B)
Every year more and more plants and animals
disappear never to be seen again.Strangely,it is the most intelligent but most thoughtless animal that is
causing most of the problems- man.Nature is very carefully balanced and if this balance is disturbed,animals can disappear alarmingly(令人担忧地)fast.Every day,thousands of species of animals
draw closer to extinction.There are countless numbers
of species which may become extinct before they are even discovered.
In many lakes the fish are dying.Fishermen are worried because every
year there are fewer fish and some lakes have no fish at all.Scientists are beginning to get worried too.What
is killing the fish?
The problem is acid rain.Acid rain isa
kind of air pollution.It is caused by factories that
burn coal or oil or gas.These factories send smoke high
into the air.The wind often carries the smoke far from
the factories.Some of the harmful substances in the
smoke may come down with the rain hundreds of miles away.
The rain in many places isn't natural and
clean any more.It's full of acid
chemicals.When it falls in lakes,it changes them too.The lakes become more
acidic.Acid water is like vinegar or lemon juice.It hurts when it gets in your eyes.It also
kills the plants and animals that usually live in lake water.That is why the fish are dying in lakes.
But dead fish may be just the beginning of
the problem.Scientists are finding
other effects of acid rain.In some large areas trees
are dying.Not just one tree here and there,but whole forests.At first scientists
couldn't understand why.There were no bugs or diseases
in thesetrees.The weather was
not dry.But now they think that the rain was the cause.Acid rain is making the earth more acidic in these areas.Some kinds of trees cannot live in the soil that is very acidic.
Now scientists are also beginning to study
the effects of acid rain on larger animals.For example,they believe that some deer in
Poland are less healthy because of acid rain.If deer are
hurt by the rain,what about people?This is the question many people are beginning to ask.No one knows the answer yet.But it is an
important question for us all.
24.Every year thousands of species of animals _______ .A.are hunted for their meat and skins
B.migrate to other places
C.starve to death
D.die out
25.Acid rain is caused by _______ .
A.natural gas
B.the ozone(臭氧)layer depletion(损耗)
C.acidic lake water
D.emissions of industrial enterprises
26.Which of the following is true?
A.Dead fish in lakes is the only problem caused by acid rain.
B.Scientists are sure that acid rain is not harmful for mankind.
C.If we don't make an attempt to stop acid rain we may never see some
animals again.
D.There's no reason to worry about several trees that died of some
unknown disease.
27.What is not mentioned in the text?
A.Acid rain is capable of dissolving(分解)some
rocks and stones.
B.Fish are unable to live in the water containing acidic chemicals.
C.Coal,oil or gas form dangerous combinations
after being burnt.
D.Scientists think that if some larger animals can be affected by acid
rain,people may be in great danger.
28.Factory smoke _______ .
A.stays over the factories
B.is usually clean now C.turns into air
D.can travel hundreds of miles
29.Scientists think acid rain _______ .
A.is killing people
B.helps kill bugs
C.fertilizes the soil
D.is killing trees
30.The word bug in this context means _______ .
A.an infectuous disease
B.a small insect
C.a dangerous bird
D.a small plant