北师大版（2019）选择性必修一Unit3 Conservation Lesson1 useful expressions课件(36张ppt)

(共36张PPT)
Unit 3
Conservation
Lesson 1-(2)
Part 1—Lead in
Let’s review the passage according to the following information.
Lead in
Background history of the sixth extinction.
Causes of the sixth extinction.
Effects of the sixth extinction.
What we can do to prevent the sixth extinction.
Show time!
Lead in
Part 2—Reading comprehension
Let’s read!
Read and think
Extinctions, where entire species are wiped out, are not unusual in our Earth’s history. In fact, over 90 percent of all species that ever lived are now extinct. In the last 500 million years, there have been five times when life on Earth has almost ended. These include the third mass extinction, known as the “Great Dying”, which killed 90% to 96% of all species. And the fifth event, which occurred 66 million years ago, caused the death of the dinosaurs. The reasons for extinctions are varied. According to scientists, they include volcanic eruptions, asteroids hitting the Earth from space, changes in sea levels, the decrease of the oxygen content of the sea and global warming. Many scientists say we are now entering the Earth’s sixth mass extinction. This time, human activity will be to blame.
Although it is not unusual for species to die out naturally, the rate at which this is now happening is cause for concern. A 2015 study by scientists who were based at Brown University and Duke University in the US, looked at how quickly species die out due to natural causes, that is, the “background extinction rate”.They found that human activity is causing species to die out 1,000 times faster than normal. There is a long list of reasons why so many species are dying out: air and water pollution, forests being destroyed, factory farming and overfishing. It is clear that human activity has negatively affected all other species on Earth, including animals and plants.
Let’s read!
Read and think
If a sixth mass extinction occurs, scientists who have studied the issue believe that up to three quarters of all species on Earth could die out. Of course, as we humans depend on so many species for our survival, we would also be at risk of dying out. Our world and our lives depend on the balance in nature between animals and plants. Without forests, we would have no air to breathe, and without clean water we would be unable to survive.
Can a sixth extinction be avoided Experts say that it is not yet too late, if we take action now. This would mean we have to significantly change the way we live. For example, we need to take steps to save endangered species, including setting up special areas where plants and animals can be protected. We need to change how we work and travel by using cleaner, more natural sources of energy, such as wind and solar energy. We also need to improve our farming methods to reduce water, air and land pollution. In short, if we want to survive, we need to stop destroying the planet that we live on and start to protect it.
Extinctions, where entire species are wiped out, are not unusual in our Earth’s history.
wipe out: 彻底毁灭
wipe...with... 用……擦……
wipe sth. away/ off/ up 擦掉/擦净某物
wipe sth. off/ from... 把某物从……处擦掉
wipe sth. from/ off one’s mind/ memory 有意忘记某事
整个物种灭绝，在我们地球的历史上并不罕见。
Useful expressions
非限制性定语从句，先行词extinctions，关系副词where
In fact, over 90 percent of all species that ever lived are now extinct.
ever:
“在任何时候” ，有时可与always替换，表示“始终，一直”Honesty ever pays.
可出现在过去时态或完成时态的疑问句中。Did you ever see such a grand parade
在疑问句中，长用来加强语气。What ever do you want
事实上，有史以来90%以上的物种现已灭绝。
Useful expressions
And the fifth event, which occured 66 million years ago, caused the death of the dinosaurs.
occur: 用作动词基本含义是“呈现在视野、思想、意识中”。一般只用作不及物动词，含有“出乎意料”的意味。
The explosion occured during an exercise near the town.
有时还可用作系动词，接形容词作表语，表示“存在”。
Few metals occur free.
指“想到”时，后面跟介词to。
It occured to me to visit my teacher.
第五次事件发生在6600万年前，导致恐龙死亡。
Useful expressions
The reasons for extinctions are varied.
varied: adj. “各种各样的，形形色色的”
varitey: n. 多种样式；不同种类；多变性
a variety of styles 各种风格
variety in one’s lifestyle 生活方式的多样化
variety show 综艺节目
vary vi. &vt. 变化，改变
various adj. 各种各样的 =a variety of
物种灭绝的原因多种多样。
Useful expressions
... the decrease of the oxygen content of the sea and global warming.
decrease: 名词，表示“减少；减少的量”
动词，表示“减少”。
decrease in 在……减少
decrease to+数字 下降到……
decrease by+/分数、百分数或其他表示数量的词 下降了……
oxygen content: 氧含量
……海洋含氧量的减少和全球变暖。
Useful expressions
This time, human activity will be to blame.
blame: 责怪，指责
be to blame (for sth.) 应该为（某事）负责人
blame sth. on sb./ sth. 把某事归咎于某人/某事
blame sb. for (doing) sth. 因（做）某事而责备某人
put/ lay/ place the blame (for sth. ) on sb. 把某事归咎于某人
这一次，人类活动将是罪魁祸首。
Useful expressions
是主动形式表示被动
Although it is not unusual for species to die out naturally, the rate at which this is now happening is cause for concern.
die out: 消失；绝迹、灭绝
die away: （声音、风、光等）逐渐消失
die off: （一群生物）相继死去
die down: （慢慢地）熄灭；平息下来
rate: 比率
at the rate of... 以……之比率
虽然物种自然灭绝并不罕见，但现在这种情况发生的速度令人担忧。
Useful expressions
... that is, the “background extinction rate”.
that is: 也就是说；即（用于纠正之前说过的内容）
=that is to say
……即“背景消光率”。
Useful expressions
They found that human activity is causing species to die out 1,000 times faster than normal.
1000 times faster than: 比……快一千倍
表示倍数句式：
A is... times as long/ wide/ high/ large/ deep ...as B.
The dictionary is almost five times as expensive as that one.
A is... times longer/ wider/ higher/ deeper...than B.
The new street is 3 times wider than the old one.
A is... times the length/ width/ height/ size/ depth... of B.
China is almost twice the size of their country in area.
A is... times+what 从句
The dictionary costs three times what it did before.
A has increased/ decreased/ reduced/ gone up/ risen by...times.
The price of meat has gone up by three times.
他们发现人类活动导致物种灭绝的速度比正常情况快1000倍。
Useful expressions
There is a long list of reasons why so many species are dying out: air and water pollution, forests being destroyed, factory farming and overfishing.
destroy: 破坏；毁掉。
destroy sb. 毁掉某人（的一生）
be destroyed by fire被大火烧毁
destruction 破坏
destroyer 破坏者
overfishing: 过度捕捞
over-:前缀，表示过度
Useful expressions
这么多物种灭绝的原因有很多：空气和水污染、森林被破坏、工厂化养殖和过度捕捞。
It is clear that human activity has negatively affected all other species on Earth, including animals and plants.
It is clear that: 很明显……，it作形式主语，该句为主语从句
affect: 影响；感染；打动
be affected by... 被……所打动/影响
be affected with... 患上……疾病
effect: 效果；作用；影响
have an effect on /upon...对……有影响/效果
cause and effect因果
come into effect 开始生效；使生效
put/ bring...into effect实施；使生效
很明显，人类活动对地球上所有其他物种，包括动物和植物，都产生了负面影响。
Useful expressions
Without forests, we would have no air to breathe, and without clean water we would be unable to survive.
without和no构成双重否定，用以加强语气。
without还可以表示“如果没有”，用于虚拟语气，相当于but for。
Without his wartime experiences, Hemingway wouldn’t have written his famous novel A Farewell to Arms.
没有森林，我们就没有空气可以呼吸，没有干净的水，我们就无法生存。
Useful expressions
Experts say that it is not yet too late, if we take action now.
take action: 采取行动
专家表示，如果我们现在就采取行动，现在还为时不晚。
Useful expressions
For example, we need to take steps to save endangered species, including setting up special areas where plants and animals areas where plants and animals can be protected.
take steps:采取措施
例如，我们需要采取措施保护濒危物种，包括建立特殊的动植物保护区和动植物保护区。
Useful expressions
In short, if we want to survive, we need to stop destroying the planet that we live on and start to protect it.
in short: 简而言之
简而言之，如果我们想要生存，我们需要停止破坏我们赖以生存的星球，并开始保护它。
Useful expressions
Practice
Use the adjectives and nouns to make meaningful expressions. Then use each expression to make a sentence. Write the sentences in the space provided.
Practice
Use the adjectives and nouns to make meaningful expressions. Then use each expression to make a sentence. Write the sentences in the space provided.
1. Crucially, could it lower the global average temperature of the earth in time to avoid killing millions more people, more animals and indeed entire species
2. The panda ambassadors will visit a dozen countries to promote the protection of the endangered animal.
3. They have had a significant change in policy on paternity leave.
4. They are looking at ways of reducing the waste of natural resources.
5. Well, today we are witnessing a sixth mass extinction.
6. Solar energy can be transformed into power.
Practice
Complete the paragraph about extinctions using the correct form of the phrases below.
A
B
C
D
F
G
H
E
I
Practice
Let’s check!
A
B is known as
C
D
F
G
H
E
I
A died out
C has affected
D
G/F
G/F
H
I
E
定语从句
Focus on language
限制性定语从句&非限制性定语从句
Focus on language
The girl who is playing tennis is my friend.
This is the place where I hid the key.
限制性定语从句修饰名词或代词，表明所修饰的是哪个人或物。
Focus on language
My friend, who is playing tennis, comes from Ethiopia.
The building, where an important conference is being held, is in the centre of the city.
非限制性定语从句提供句子意义以外的额外信息，要用逗号隔开。
Focus on language
It is snowing heavily, which makes children feel excited.
The river is seriously polluted, which has caused much public attention.
非限制性定语从句中的关系代词可以指代整个句子。
1 Extinctions, where entire species are wiped out, are not unusual in our Earth’s history.
2 These include the third mass extinction, known as the “ Great Dying”, which killed 90% to 96% of all species.
3 A 2015 study by scientists who were based at Brown University and Duke University in the US, looked at how quickly species die out due to natural causes...
4 If a sixth mass extinction occurs, scientists who have studied the issue believe that up to three quarters of all species on Earth could die out.
5 We need to take steps to save endangered species, including setting up special areas where plants and animals can be protected.
Practice
Read the sentences and discuss which word(s) the clauses (in italics) refer to.
2/3/4
1/2
Practice
Underline the relative clauses in the sentences and decide if they are defining(D) or non-defining (ND). Translate them into Chinese. Discuss the difference in meaning between the two types of relative clauses.
D
D
ND
ND
ND
Group Work
Choose two or three environmental problems that are caused by human activity. Offer solutions. Try to use relative clauses where appropriate.
Part 3—Homework
Recite the key words and expressions.
Write the sentences to match the endings.
Example ___, which was quite a surprise.
My painting won the first prize, which was quite a surprise.
1 _____________________, which made me angry.
2 _____________________, who isn’t very kind at all.
3 _____________________,which I really liked.
4 _____________________,whose cousin is coming to town.
Homework
Example ___, which was quite a surprise.
My painting won the first prize, which was quite a surprise.
5 _____________________,which changed my plans for the future.
6 _____________________, where the storms can be terrible.
7 _____________________, which scared me to death.
8 _____________________,which I borrowed from my friend.
Homework