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Unit
5
A fine
balance
that which
We depend on each other in the ecosystem of the earth.In this unit,let's learn about
ecological protection.What are our influences on ecosystems How can we help protect
ecosystems What are our achievements in ecological protection By the end of this unit,
you will write a research report on people's efforts to keep ecosystems balanced.
After completing the unit,you will be able to:
use words and expressions in the unit to talk about ecosystems.
use attributive clauses with that and which to talk about humans'influence on
ecosystems.
explain the importance of ecological balance.
66 UNIT 5
What can you see in the picture
Starting out
Look at the pictures and match them with the words.
wetland
grassland
rainforest
desert
river
a
NN方
d
Look at the picture and answer the questions.
What is an ecosystem
1 What things can you find in an
ecosystem
2 How can people influence
ecosystems
1.
2
A fine balance 67
Understanding ideas
Look at the word cloud and predict what the passage is about.
people disappearincrease
cut down pollution get along with
drop
nature
2
Read the passage and check your prediction.
When the earth
disappear from:
2.increase:v./n.
1.2007
decrease:v./n.
ls still
、
ecosystem:n.
1 In 2007,writer Alan Weisman wrote a book called The World
Without Us.In the book,he showed his readers a world without
humans.Let's imagine such a world.All human activities stop.
Cars disappear from the roads,boats from the rivers,and planes disappear
from the skies.Streets,beaches and parks that are usually full of
people remain empty.If people are gone,what would happen to
the natural world
2is no surprise that animals would soon increase in number.In
2.
cities,traffic noise often means fhat animals cannot easily hear
each other Without humans,the noise would drop greatly as traffic
stops This allows natural sounds to fill the air.is much easier
for animals to find each other and form families.Also,tourists
disappear from beaches and seas.Sea animals would not be
troubled by people around them.
3 But not only animals would enjoy the change.Ecosystems would
start to balance again,too.Trees would grow freely without the
68 UNIT 5

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