课件34张PPT。Unit 7
The World Is a Big PlaceLesson 38 冀教版英语八年级下册Think about it!? How many continents are there in the
world? What are they?
? What do you know about the place
where you live? How many continents are there in the
world? What are they?AfricaAsiaEuropeOceaniaAntarcticaSeven ContinentsNorth AmericaSouth AmericaThe Pacific OceanThe Indian OceanThe Atlantic OceanThe Arctic OceanOceans cover about three-quarters of the earth’s surface.desertDeserts cover twenty percent of the earth’s surface.What’s the world’s biggest island? The world’s biggest island is Greenland. Greenland is northeast of Canada.GreenlandWords & expressionsListen and read. The earth is a very special planet, and it faces a big problem. In the year 2010, the world’s population was over 7 billion in total. It is increasing very quickly. By 2025, the worldmay have about 8 billion people. And by 2050, the world’s population may reach 9 billion.
There is another problem. People can’t live everywhere on the earth. We can’t live in water, and only about one third of our planet is land. But parts of this land are very dry. These dry places are called deserts. Some areas have very high mountains. Others have a lot of snow and ice. It is not easy to live in those places. There are seven continents: Asia, Africa, Australia, Antarctica, Europe, North America and South America. Antarctica is covered with snow and ice all year round. Luckily, people can live on the other six continents. On these continents, there are green forests, fresh water and rich lands.
Oceans cover two thirds of the earth’s surface. The earth has only one big ocean, butwe use these names for its different parts: the Pacific Ocean, the Indian Ocean, the Atlantic Ocean and the Arctic Ocean. The Pacific Ocean is the largest one.
The earth is our home now, and it will be our home in the future. It must be treated well for our children and for our children’s children, too!Language pointsIn the year 2010, the world’s population
was over 7 billion in total.
在2010年，世界人口总数超过770 亿。
in total = in all,意思是“总计，合计”。例如：
How many snakes in total?
一共有多少条蛇？
There are more than 6 000 students in our
school in total. 我们学校的学生总计达6 000多。2. It is increasing very quickly.
(世界人口)正在 迅速增长。
increase, 动词，意思是“增加；增大；增长；
增强；繁殖”，后接介词by表示“增加了……”
接介词to表示“增加到……”。例如：
The population has increased from 300 000 to
70 000 000.人口己经从三十万增加到了七千万。
The company has increased the price of its cars.
公司提高了汽车价格。3. And by 2050, the world’s population may reach 9 billion.
到2050年，世界人口总数可能会达到 90亿。
1)“by+时间”表示“到……为止”。例如：
I promise I’ll send you feedback by this Friday.我 保证在这个星期五前给你反馈。
We had to get there by evening.
我们最迟也要在傍晚到达那里。 2)reach在本句中的意思是“达到”。例如：
We’re told the figure could reach 100 000 next year. 我们得知明年这一数字可能达到十万。
This year it may not reach even that.
今年有可能还达不到这一水平。4. We can’t live in water, and only about one third of our planet is land.
我们不能居住在水里，而全球只有三分之一的面积是陆地。
1)one third of our planet意思是“我们星球的三分之一”，one third 表示分数 1/3。
分数的表达方法比较常见的有：
a)基本表达法: 分子用基数词，分母用序数词， 例如：1/5 one fifth 1/9 one ninthb) 如果分子大于1,分母要用序数词的复数形式,
例如：2/5 two fifths ; 7/9 seven ninths
c) 特殊分数表达法： half意思是“一半”，可以用来表示1/2;2) quarter名词，意思是“一刻钟，四分之一”。例如： 1/2 one half
1/4 a quarter
3/4 three quarters
Half of us are from North China.
我们当中有一半来自于华北地区。
A quarter of the students have left their pictures home. 四分之一的学生把照片落在家里了。5. Antarctica is covered with snow and ice all
year around.
北冰洋常年被冰雪覆盖。
be covered with意思是“被 所覆盖”。例如：
The field is covered with so many beautiful
flowers.
田野被许多美丽的花儿所覆盖。 Read the lesson and match each paragraph
with its main idea 1Paragraph 1
Paragraph 2
Paragraph 3
Paragraph 4
Paragraph 5a. Six of the seven continents are
good for people to live on.
b. We should treat the earth well.
c. An increasing population is a
big problem for the earth.
d. Two thirds of the earth is
covered with oceans.
e. People cannot live everywhere
in the earth. Fill in the blanks with the correct forms
of the words in the box.2The number of swimmers here is _________
quickly because it’s very hot these days.
2. The school has a ______ of 900 students.
3. I think it may be the ______season of the year.
4. The _______ of our body is skin. It protects us.
5. How many _______ of people are there in the
world now?increase dry surface billion totalincreasingtotaldriestsurface billions Match the seven continents with their
correct descriptions.3in total
one third
be covered with总计；合计；总共
三分之一
被……覆盖ExerciseI. Choose the best answers:BA( ) 1. ____ of the students are from the
countryside.
A. Third quarter B. Three quarters
C. Three quarter D. Third quarters
( ) 2. A quarter of the students ____ let their
books at home.
A. are B. is
C. have D. has ( ) 3.The Yellow River is ______ in
China.
second longest river
the second longest river
C. the second longest rivers
D. the longest riverBThey will be there _________________ ( 在周末以前).
_______________ (四分之三) of the
apples are green.
3. Milk _____________ (对……有益）your health.
4. The world _____________ (由……组成）many different kinds of places.by the weekendThree quarters is good foris made up ofII. Fill in the blanks.III. Fill in the blanks.There are continents in the world. Africa,
, Australia, , North America,
and Antarctica. is
the world’s coldest continent. There are four
oceans: , _______________, the
Indian Ocean and . The
biggest island in the world is . The
longest river in the world is .sevenAsiaEurope South AmericaAntarcticathe Pacific Ocean the Atlantic Oceanthe Arctic OceanGreenland the Nile River Search more information about the knowledge of our earth and share with your partners.HomeworkThanks!
