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Unit 7
The natural world
Reading
01
02
学习目标
03
能通过阅读，了解生态系统的基本概念以及地球上三大生态系统的分布、功能与重要性等相关信息，理解明喻的修辞手法。
能探讨人类活动对生态环境的影响，增强生态保护的意识。
能掌握本课时的重点单词、短语和句型。
We all know everyone has a heart, kidneys and lungs. Do you know what the heart, kidneys and lungs of the earth are
Lead in
Simon is reading an article about the three main ecosystems on earth. Here is the article. Before reading, think about the questions below.
1 What kinds of things do you think are in an ecosystem
In an ecosystem, there are plants, animals, microorganisms（微生物）, soil, water, and air.
2 What do you know about oceans, wetlands and forests
Oceans cover a large part of the Earth. There are many kinds of fish and other sea creatures. Wetlands are areas with water and they’re home to many birds and other animals. Forests have a lot of trees, wild animals, and different plants. They are important for the air we breathe and for wildlife habitats.
Before reading
新课讲授
TIP
Similes create similarity between two different things by using words such as like and as and help the reader better understand the content.
A Look at the picture and choose the correct descriptions for each ecosystem according to the article. Write the correct letters in the boxes.
a Cover 71% of the earth's surface
b Cover nearly a third of the earth’s land area
c Help clean the water
d Help make the air clean
e Help prevent floods
f Produce about 70% of the earth's oxygen
g The “heart” of the earth
h The ”lungs“ of the earth
i The “kidneys” of the earth
b, d, h
a, f, g
c, e, i
While reading
B Read the article again. Choose the correct answers to the questions.
1 What is an ecosystem made up of
a Oceans, wetlands and forests.
b Plants and animals.
c Living and non-living things.
c
2 Why is the ocean the largest ecosystem of the three
a It holds plenty of the earth’s water.
b It makes up about 71% of the earth's surface.
c It is home to many kinds of plants and animals.
3 What do wetlands do during heavy rains
a They make the water clean.
b They hold water.
c They get rid of water.
b
b
4 “They also trap harmful things in their leaves and help clean the air.” Which word can we use to replace the word ”trap“
a keep b drive c produce
5 Where can we read this kind of article
a In a newspaper.
b In a travel guide.
c In a geography magazine.
6 How does the author show the importance of oceans, wetlands and forests
A. By making comparisons.
B. By giving definitions.
C. By presenting data and functions.
D. By telling historical facts.
a
c
c
关键词定位法
关键词定位法是指通过识别和理解题目中的关键信息（即关键词），然后在文章或段落中迅速找到这些关键词，从而定位到与题目相关的内容，进而找到答案的方法。如第1小题，我们可以通过题干中的“an ecosystem”，定位到文章的第一段，然后快速找到关键信息“living and non-living things”，即可选出答案c。
C Simon is listening to a podcast about the ocean plete the script with the correct forms of the words and phrases in the box below.
balance be home to surface oxygen
get rid of take in store role
The biggest ecosystem
Hello listeners! Welcome to Science with Doctor Ted. Today I'll talk to you about the biggest ecosystem on our planet.
Do you know what it is Yes, it’s the ocean. It covers the largest area of the earth’s (1) __________ and holds 97% of the earth's water. It (2) __________ many animals and plants.
surface
is home to
balance be home to surface oxygen
get rid of take in store role
Do you know that some of the plants in the ocean produce (3) __________ for the animals living there What’s more, the ocean can (4) __________ 25%-30% of carbon dioxide and (5) __________ heat. It plays an important (6) __________ in slowing down climate change.
Sadly, we're facing a serious problem: ocean pollution. There are millions of tons of plastic in the ocean and it’s very difficult to (7) __________ it. It's time for us to take action and protect the ocean. If we don’t, the plastic will harm the (8) __________ of the ocean ecosystem.
oxygen
take in
store
role
get rid of
balance
D Think about the questions below. Share your answers with your classmates.
1 Why are the three ecosystems important for the earth
Because each ecosystem has a role to play and helps keep the balance between all its members and the greater environment.
2. Besides the oceans, wetlands and forests, what other ecosystems do you know
I also know the grassland ecosystem, the desert ecosystem, the river ecosystem, the lake ecosystem, the urban （城市的） ecosystem and agricultural（农业的） ecosystem.
After reading
3 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, soil, and sunlight. They are extremely important. For example, sunlight is the primary source of energy for most ecosystems.
4 How do human activities affect the ecosystems Give an example.
Human activities can have both positive and negative impacts on ecosystems. Here is an example of the negative impact: Humans cut down large areas of forests for various reasons such as building houses and making furniture. This destroys the habitats of many wild animals and plants.
1. The earth’s main ecosystems 地球主要生态系统
生态系统指在一定空间范围内，所有生物与相应的环境相互作用、相互影响而形成的统一整体。一条河流、一片森林，甚至整个地球，无论地域是小还是大，都可以看成一个生态系统。海洋、湿地和森林并称为地球三大生态系统。海洋被喻为“地球之心”，湿地被喻为“地球之肾”，森林被喻为“地球之肺”。
Language points
include 动词，意为“包括”，强调一个整体包含着若干个独立部分,或者一个东西包含着另一个东西的一部分。include... in 是一个动词短语，意为“把……包括在内”。
including 是include的动名词形式,但通常独立用作介词,意为“包括……在内”，常和前面的内容用逗号隔开。
2. An ecosystem includes all the living and non-living things in an area.
生态系统包括一个地区的所有生物和非生物。
e.g. The school includes 30 teachers and 500 students.
这所学校包括30 名老师和500 名学生。
A visit to Beijing must be included in our plan.
参观北京必须列入我们的计划。
There are all kinds of animals in the zoo, including bears, lions and so
on.动物园里有许多种动物，包括熊、狮子等。
3. Each ecosystem has a role to play and helps keep the balance
between all its members and the greater environment.
每个生态系统都要发挥作用，从而帮助保持其所有成员和更
大的环境之间的平衡。
句中的 have a role to play 表示“发挥作用，有责任”，动词不定式 to play 充当定语，修饰前面的名词 role，并与名词构成动宾关系。
e.g. I have a report to write this afternoon. 今天下午我有份报告要写。
There are lots of things to do in the park. 在这个公园有许多事情可做。
4. It covers around 71% of the earth's surface and produces about 70% of
the earth’s oxygen. 它覆盖了地球表面约71%的面积，产生了地球上约
70%的氧气。
around 作副词,意为“大约”，用于表示数量、时间、年龄等的不确切或近似数。
around 还可以作介词，意为“在……周围”。
look around 意为“环视；向四周看”。
e.g. It took me around an hour to finish my homework.
我花了大约一个小时完成作业。
The children are playing around the garden. 孩子们在花园周围玩耍。
He looked around but saw nothing.他环顾四周可是什么也没有看见。
5. It holds plenty of salt water, and the water rises to the sky, falls onto the
land and then returns to the ocean. 它含有大量的盐水,水上升到天空,落
在陆地上,然后回到海洋。
(1) 本句描述了自然界的“水循环”现象。水在地球系统中连续不断地循环运动，水分由海洋输送到大陆，又回到海洋的循环为“大循环”或“外循环”。水分由陆地蒸发到大气，又回到陆地，或由海洋蒸发到大气，又回到海洋的循环为“小循环”或“内循环”。
(2)hold vt. 容纳；拿着；举行
拓展:
hold 作动词，有以下几种意义：
①容纳：指某个空间的大小能装下一些人或物；
②拿着：指用手拿着某些物品；
③举行：指举行会议或活动；
④承载、支撑：指承载某种物体的重量。
hold on 别挂断电话；稍等
hold off = put off 推迟
e.g. The room can hold 200 people. 这个房间可以容纳200 人。
He held a pen in one hand and a ruler in the other.
他一只手拿着钢笔另一只手拿着尺子。
We’ll hold a sports meeting next week.
下周我们要举行运动会。
The roof couldn’t hold the weight of snow.
屋顶承载不了雪的重量。
Hold on, please. I’ll get my friend.
请别挂断，我去叫我的朋友。
They decided to hold off(推迟) the meeting until next Sunday.
e.g. He returned to his hometown after many years.
多年以后他返回了家乡。
You must return the book to the library before Monday.
周一以前你必须把书还给图书馆。
What can I do in return for your kindness
我怎样做才能回报你的好意呢？
(3)return 作动词,意为“返回;回去,回来”,常用短语:return to +地点,意为“返回某地”。return 还可以表示“归还”,构成短语:return sth. to sb. 把某物归还给某人
in return 作为回报
6. Plants in wetlands help get rid of pollution and make the water clean.
湿地中的植物有助于消除污染,使水变得清洁。
get rid of 意为“清除；摆脱；丢弃”,表示清除某种不良影响；摆脱某人或某种困境；丢弃不想要的物品等。
e.g. You must get rid of your bad habit of getting up late.
你必须改掉晚起的坏习惯。
The hunter wanted to get rid of the wolf, but he couldn’t.
猎人想要摆脱那头狼，但是他不能。
John decided to get rid of his old books. 约翰决定清理他的旧书。
7. Wetlands can also help prevent floods.湿地也有助于防止洪水。
prevent 作动词,意为“防止,阻止”,后面可以直接加名词或代词作宾语。prevent sb. from doing sth. 是其常用短语，意为“阻止某人做某事”。
e.g. The government are taking action to prevent pollution.
政府正在采取措施防止污染。
We tried to prevent him, but we failed.
我们试图阻止他，可是没有成功。
The rain prevented us from going out to play.
雨阻止了我们外出玩耍。
8. During heavy rains, wetlands store water like giant sponges.
在大雨期间，湿地像巨大的海绵一样储存水。
store 作动词,意为“贮存；存储”,后面可以直接接名词作宾语。store up 意为“储存；积累”。
store 还可以作名词，意为“商店；仓库”。
e.g. The pond stores much rainwater in summer.
这个池塘夏天储存很多雨水。
The little squirrel stores up food in a tree hole in winter.
冬天小松鼠把食物存在一个树洞里。
I went to the store to buy some groceries.
我去商店买了一些杂货。
9. They act like the “kidneys” of the earth.它们就像“地球的肾脏”。
act 可作不及物动词,意为“起作用;行动”,也可作及物动词,意为“扮演”,主要表示以下意义：(1)起作用:表示某种东西或话语对另一种东西或某人产生影响；(2)行动:表示采取行动来解决问题或实现目标；(3)表现:表示人的行为方式，描述人的举止或态度；(4)扮演:表示在戏剧或电影中扮演某个角色。
take action 采取行动 act like 表现得像……
act as 充当；担任 act out 表演出来
e.g. The medicine acts mainly on the central nervous system.
这种药主要作用于中枢神经系统。
We need to act quickly to solve the problem.
我们需要立即行动来解决问题。
The new student acts very well in class.那个新生在班里表现很好。
He acted the part of a doctor in the TV play.
在那部电视剧中他扮演了医生的角色。
The government must take action to prevent pollution.
政府必须采取措施制止污染。
She acted as the team leader during the match. 比赛期间她担任队长。
10. Forests make up nearly a third of the earth's land area.
森林占地球陆地面积的近三分之一。
make up 的意思主要有:(1)占据总量中的一定分量(2)编造故事或借口(3)组成(一个集体或团队)(4)化妆；打扮。
e.g. Women teachers make up a half of the teachers in this school.
女教师占据了本校教师的一半。
The teacher made up a funny story for his new lesson.
老师为他的新课编了一个有趣的故事。
We need two more players to make up a soccer team.
我们还需要两名队员来组成足球队。
She spends too much time making up in the morning.
早上她花太多时间来化妆。
11. Plants there take in carbon dioxide from the air and produce oxygen.
那里的植物从空气中吸收二氧化碳并产生氧气。
take in 吸收
e.g. They will certainly need to take in plenty of liquid.
它们当然需要吸收大量液体。
12. They also trap harmful things in their leaves and help clean the air.
它们还能在叶子中捕获有害物质，帮助清洁空气。
If we don’t, the plastic will harm the balance of the ocean ecosystem.
如果我们不这样做,塑料将破坏海洋生态系统的平衡。
harm可作动词或名词，意为“伤害；损害”，其形容词形式是harmful，意为“有害的”。常用短语：do harm to 意为“对……有害”(harm 是名词)；be harmful to 意“对……有害”。
e.g. Running too much may harm your knees.跑步过多可能伤害你的膝盖。
Smoking harms our health. 吸烟有害我们的健康。
Reading in the sun does harm to your eyes.在阳光下读书对你的眼睛有害。
Smoking is harmful to our health. 吸烟有害我们的健康。
13. Each of these ecosystems support millions of plants and animals.
这些生态系统中的每一个都支持这数以百万计的动植物。
millions of 数以百万计的
归纳拓展
hundred (百)、thousand (千)、million (百万) 都是表示数量的词，它们的用法是：表示具体数量时不使用复数，表示笼统数量时要使用复数，且后面要加介词of。
e.g. You can see millions of stars in the sky at night.
晚上在天空中你会看到数以百万计的星星。
Thousands of tourists come to Beijing every year.
每年成千上万的游客来北京。
In summer, you can see hundreds of ducks on the river.
夏天，在河面上你会看到成百上千的鸭子。
14. It’s time for us to take action and protect the ocean.
是我们采取行动和保护海洋的时候了。
It’s time （for sb.) + 动词不定式.是一种常用的句式结构，意为“（某人）该做某事了”。也可以直接使用“It’s time for + 名词”。
e.g. It’s time to have lunch. 该吃午饭了。
It’s time for children to go to bed. 孩子们该睡觉了。
It’s time for Chinese class. 该上语文课了。
1.The price for the hotel room is 235 dollars a night, _____________ (include) breakfast.
2.If you know about the ________________ (important) of study, you will work much harder.
3.Cells (细胞) are the smallest and most basic units of____________ (live) matter.
4.About two thirds of the earth's surface _________________ (be) covered with water.
5.If we don't take action to stop ________________ (pollute), there will be less fresh water.
including
importance
living
is
pollution
一、用所给单词的适当形式填空
当堂检测
1. 由于天气原因，我们只好把运动会推迟到下周。
We had to______ _____the sports meeting till next week because of the weather.
2.然后他们返回到他们自己的座位。
Then they __________ ________ their own seats.
3. 父母总是试图阻止孩子玩太多游戏。
Parents always try to their children ______ _______ games too much.
4. 动物们需要为冬天贮存食物。
Animals need ______ ______ ______ food for winter.
5. 在自然界中，森林扮演了自然卫士的角色。
In nature, forests ______ _____ the natural guardians.
hold/put off
returned to
prevent from playing
to store up
act as
二、翻译句子
6. 喝太多果汁对儿童的牙齿有害。
Drinking too much juice can ________ _____________ ____ children’s teeth.
7. 我们必须要清除这个地区的污染。
We must ______ _______ ______ the pollution in this area.
8. 尽管你迟到了可是你不应当编造借口。
Although you were late, you shouldn’t ________ ______ excuses.
9. 冬天，数以百万计的鸟儿飞向南方。
In winter, __________ ______ birds fly to the south.
do/be harm /harmful to
get rid of
make up
millions of
Search more information about other ecosystems and talk about them next lesson.
Preview Grammar on pages 98-99.
Homework

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