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(共22张PPT)
Reading
Unit 7 The natural world
八年级上册
Revision
Speak out!
Which of the following ecosystems do you know best
Pre-reading
What kinds of things do you think are in an ecosystem
plants
animals
…
Living things
Non-living things
air
water
soil
sunlight
…
An ecosystem
Pre-reading
What do you know about oceans, wetlands and forests
Prediction
Prediction
1. What is the article about
It’s about the three main ecosystems on earth—oceans, wetlands and forests.
2. What can you see in the pictures
Picture 1: I can see dolphins and the ocean.
Picture 2: I can see birds and a wetland.
Picture 3: I can see trees and a forest.
3. What type of text is the article
It’s an expository text.
While reading
1. Listen to the article and analyse its structure.
Main ideas Paragraph(s)
What is an ecosystem (1) __________________
What are the three main ecosystems (2) __________________
How important are the ecosystems (3) __________________
1
2–4
5
While reading
2. Scan the article and finish Part A on page 96.
b, d, h
c, e, i
a, f, g
While reading
3. Read the article again and finish Part B on page 96.
While reading
Paragraph 1
Read the following sentences. Write a T if a sentence is true or an F if it is false. Then correct the false one(s).
_______ 1. An ecosystem includes only living things in an area.
_______ 2. Ecosystems are always large, like grasslands or oceans.
_______ 3. Every ecosystem has a special role and helps keep the planet balanced.
F
F
T
all the living and non-living things in an area.
can be of different sizes.
While reading
Paragraph 2–4
E
c
o
s
y
s
t
e
m
s
The ocean—
the “ (1) _________”
of the earth
· (2) _________ around 70% of the earth’s
oxygen
· Support the water cycle


Wetlands—
the “ (3) _________”
of the earth

Forests—
the “ (6) _________”
of the earth

· Be home to around 40% of all the types of
plants and animals
· Help (4) _________ pollution and make the
water clean
· Help prevent floods by (5) ___________ like
huge sponges


· (7) _________ carbon dioxide and produce
oxygen
· (8) ___ harmful things and help clean the air
heart
Produces
get rid of
kidneys
storing water
lungs
Take in
Trap
While reading
Paragraph 5
What does each of these ecosystems support
Each of them supports millions of plants and animals.
While reading
Post-reading
Finish Part C on page 97.
surface
is home to
Post-reading
oxygen
take in
store
role
get rid of
balance
Consolidation
Introduce the earth’s main ecosystems with the help of the chart below.
The ocean
The ocean is a … It covers … and produces … It holds …, and … rises to …, falls onto … and then returns to … This goes on and on, so the ocean is just like …
Wetlands
Wetlands only cover … But they are home to … Plants in wetlands help get rid of … and … Wetlands can also help prevent … During heavy rains, wetlands store … They act like …
Forests
Forests make up … Plants there take in … and produce … They also trap … and help clean … Therefore, …
Appreciation —— Simile
Read the tip about similes on page 95 and underline the sentences that use similes.
Appreciation —— Simile
Appreciation — Simile
The ocean is just like the “heart” of the earth.
Wetlands store water like giant sponges.
They act like the “kidneys” of the earth.
Why does the writer use similes in these sentences
The writer uses similes to make it easier for readers to understand the importance of ecosystems. By comparing the ocean to one part of the human body and comparing wetlands to huge sponges, the writer helps readers understand how these ecosystem work and why they are important for life on earth. The similes also make the information more interesting and easier to remember.
Discussion
1. Why are the three ecosystems important for the earth
The ocean, wetlands and forests are important because they help keep the earth’s air and water clean, and support millions of plants and animals. They keep the planet healthy and make our world a better place.
2. What are some of the non-living things in an ecosystem Are they
important Give reasons.
Some non-living things in an ecosystem include water, air, sunlight, soil and minerals. They are important to an ecosystem because they provide the necessary conditions for living things to survive.
Homework
Think about the questions below. Share your answers with your classmates.
How do human activities affect the ecosystems Give an example.
Thank you!

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