1、Unit 3 ConservationLesson 1 The Sixth Extinction 教学目标与核心素养：知识目标：Students can learn some new words and expressions and attributive clause.能力目标：Students can have a further understanding of the passage.情感目标：Students can think individually and learn cooperatively.教学重难点教学重点：How to learn the new words and
2、 expressions and attributive clause.教学难点：Howto make students have a better understanding of the passage.课前准备：多媒体，黑板，粉笔教学过程：一、Pre-reading1. Greeting2. Leading-inACTIVATE AND SHARE教师活动：(1) 教师活动，引导学生完成练习。How much do you know about extinction? Choose the option based on your knowledge.1 How many times u
3、p to today has life on Earth almost died out?a Once. b Five times. c More than 10 times.2 About what percent of all species on Earth became extinct during the mass extinction known as the Great Dying?a Less than 10%. b Nearly 50%. c More than 90%.3 What do scientists think will cause the next mass e
4、xtinction?a Human activity. b Natural causes. c Unknown reasons.Ask for volunteers to share their answers, encourage them to give reasons to their answers.二、 While- readingREAD AND EXPLORE1. 学生活动：阅读文章，回答问题。Read a text about extinction. Then check your answers in Activity 1.(Answers:b, c, a)Whats the
5、 text mainly about?(The text is about extinction and its effect on our planet.)2. 学生活动：阅读文章，完成练习。Read the text. Complete the notes. Then talk about the different aspects of extinctions.(Answers:1 Meaning of extinction: entire species are wiped out2 The number of extinctions occurred so far: over 90%
6、 of all species that ever lived3 Two notable extinctions and their consequences: the third mass extinction, killed 90% to 96%of all species; the fifth event, which occurred 66 million years ago, caused the death of thedinosaurs4 Main reasons that cause extinctions: volcanic eruptions, asteroids hitt
7、ing the Earth fromspace, changes in sea levels, the decrease of oxygen content of the sea, global warming5 How to avoid the sixth mass extinction: change the way we live, including setting up specialareas where plants and animals can be protected; change how we work and travel by using cleaner, more
8、 natural sources of energy; improve our farming methods)3. 学生活动：阅读文章，回答下列问题。Read again. Answer the questions.1 What did scientists find out in 2015?(The study found that how quickly species die out due to natural causes, that is,thebackground extinction rate. They found that human activity is causin
9、g species to die out 1, 000 times faster than normal.)2 Why does the writer think the sixth mass extinction will come? (Because human activity has negatively affected all other species on Earth, including animalsand plants.)3 Why does the writer believe well probably die out if 75% of the Earths spe
10、cies die out?(Because our world and our lives depend on the balance in nature between animals andplants.)4 What did people do in the case study to protect black robins? Which claim(s) did the case study support in the text?(People protected Old Blues eggs, helped them to hatch, and took care of the
11、chicks. Peopleare restoring their habitats and removing pests like mice and cats from the islands where they live. The case study showed that even in desperate situations, we can do something to help. In short, its never too late.)三、After-reading1. 学生活动： Group Work. Think and share.1 Use different c
12、oloured pens to highlight at least one example for each of the four elements listed below in different colours. Then find out (1) what typical language is used? (2)What text type is this piece of writing?(3)What is its communicative purpose?facts opinions/predictions reasons solutions(Suggested Answ
13、ers:1. (1) Facts: over 90% of all species that ever lived are extinct; the “Great Dying, which killed 90% to 96% of all species; human activity is causing species to die out 1, 000 times faster than normal.Reasons: air and water pollution, forests being destroyed, factory farming and overfishing are
14、 causing species to die out; without forests, we would have no air to breathe and without clean water we would be unable to survive.Opinions/predictions: many scientists say we are now entering the Earths sixth mass extinction; scientists believe that up to three quarters of all species on Earth cou
15、ld die out.Solutions: 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 andtravel; we also need to improve our farming methods(2) This piece of writing is an exposition.(3) Its purpose is to e
16、xplain what the sixth extinction is and its effects and call on people to take action to prevent it from happening.)2. What ways of argument does the writer use to convince readers? Are you convinced? Why or why not?(Suggested Answers:The writer uses ways such as citing ideas from experts or authori
17、ties, giving examples and using data. I believe that if we take action now it is not too late to save other species from extinction. The black robin was saved from extinction when only five birds remained, so l think it is possible to save any species if we act right now.)2. 学生活动：完成练习。Use the adject
18、ives and nouns to make meaningful expressions. Then use each expression to make a sentence. Write the sentences in the space provided.(Answers: endangered animals, entire species, natural resources, significant change, mass extinction, solar energy)3. 学生活动： 完成练习。Complete the paragraph about extincti
19、ons using the correct form of the phrasesbelowdie out be known as have affected depend on wipe outtake steps take actions set up take care ofIn the last 500 million years, there have been five mass extinction events on Earth. In the third event, which 1 _ the Great Dying, 90% to 96% of all species 2
20、 _. Of course, species died out due to many causes. But nowadays, human activity 3 _ all types of species that we 4 _ for living. We need to 5 _ toavoid the sixth mass extinction. We should 6 _ to save endangered animals andplants,and 7 _ special areas to 8 _ them before the next extinction comestha
21、t may 9 _ the entire species.(Answers:1 is known as 2 died out 3 has affected 4 depend on 5 take action6 take steps 7 set up 8 take care of 9 wipe out)四、FOCUS ON LANGUAGE: RELATIVE CLAUSES (4) -DEFINING AND NON-DEFINING CLAUSES1. Read the sentences and discuss which word (s) the clauses (in italics)
22、 refer to.1 Extinctions, where entire species are wiped out, are not unusual in our Earths 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
23、, 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 wher
24、e plants and animals can be protected.Which of the clauses above:(1) give information to identify the persons/objects. (_)(2) give extra information about a person or a thing, which can be left out. (_)(Answers:1 Refers to extinctions 2 Refers to the Great Dying 3 Refers to scientists 4 Refers to sc
25、ientists 5 Refers to special areas (1) defining clause (2) non-defining clause)2. 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.( ) 1 H
26、e went to a city where iron was produced in huge quantities.( ) 2 The bus which was full of tourists stopped near the Leaning Tower of Pisa.( ) 3 Melissa lent me some money, which was very generous of her.( ) 4 The ground is covered with snow and ice, which makes driving very dangerous.( ) 5 I met t
27、he famous professor in the hotel, where the meeting was held.(Answers: 1 D 2 D 3 ND 4 ND 5 ND)EXPRESS YOURSELF学生活动：Group WorkChoose two or three environmental problems that are caused by human activity. Offer solutions. Try to use relative clauses where appropriate.语法：定语从句在句中充当定语修饰名词或代词的句子叫定语从句。被修饰的
28、名词或代词叫先行词，引导定语从句的词叫关系词。定语从句可分为两大类：限制性定语从句和非限制性定语从句。对比两句：This is the house which/ that we bought last month.这是我们上个月买的那幢房子。The house,which we bought last month, is very nice.这幢房子很漂亮，是我们上个月买的。限制性定语从句是句中不可缺少的组成部分，主句和从句之间不用逗号隔开引导词：关系代词和关系副词，做宾语时一些关系代词可以省略非限制性定语从句是对主句先行词的补充说明，没有这一从句不影响主句意思完整。一般用逗号把主句和从句分开
29、引导词：who, whom, whose, which, when, where等，不用一般that，不能省略限制性定语从句的先行词只能是名词或代词，而非限制性定语从句的先行词可以是名词或代词，也可以是短语或句子。Then he met Mary,who invited him to a party. 后来他遇到了玛丽，玛丽邀请他参加晚会。（who指代 Mary）He changed his mind,which made me very angry.他改变了主意，这使我很生气。（which指代逗号前的整个主句）1.定语从句的关系词分为关系代词和关系副词两类。关系代词先行词作用备注who人主语
30、关系代词whom, which, that在从句中做宾语时常可以省略，但在介词后不能省略。whom人宾语whose人、物定语that人、物主语、宾语which物、句子主语、宾语as人、物、句子主语、宾语as做宾语时一般不省略关系副词先行词作用备注when时间时间状语相当于“介词+which”where地点地点状语相当于“介词+which”why原因原因状语相当于“for+which”2.关系代词的用法（1）只能用that引导定语从句的情况： 当先行词是 everything,anything,nothing,all,none,few,little,some等不定代词时，或当先行词被every,
31、any,all,some,no,little,few,much等词修饰时。如：There seems to be nothing that is impossible to him in the world. 对他来说，世界上似乎没有什么不可能的事情。 当先行词被序数词修饰时。如：The first American movie that I watched was Titanic. 我看的第一部美国电影是泰坦尼克号。 当先行词被形容词最高级修饰时。如：This is the best museum that I have visited all my life. 这是我这辈子参观过的最棒的博
32、物馆。 当先行词被 the very,the only,the first/last 等修饰时。如：She is the only person that understands me. 她是唯一理解我的人。 当先行词前面有who,which等疑问代词时。如：Which is the room that Mr Wang lives in?王先生住的是哪一个房间？ 当先行词既指人又指物时。如：Look at the man and his donkey that are walking up thestreet. 瞧瞧那个正在街上走的人和他的驴子。（2）只能用which引导定语从句的情况： 关系
33、代词前有介词时只能用which。如：This is the room in which she lived. 这是她住过的房间。 在非限制性定语从句中，关系词指物时只能用which。如：He will make a trip to Suzhou, which is famous for its beautiful scenic spots. 他将到苏州去旅行，那里因其美丽的景点而闻名。 先行词本身是that时只能用which。如：The clock is that which tells the time. 时钟显示时间。（3）用as引导定语从句的情况： 在限制性定语从句中，当先行词被 the
34、 same,such,as修饰时，定语从句用as引导。如：Such problems as are often mentioned should be solved. 类似这样经常被提及的问题应该得到解决。He would like to use the same pen as I used yesterday. 他想用我昨天用过的同一支笔。I will read as many books as are required. 要求读多少书我就读多少书。 在非限制性定语从句中，as和which都可以用于指代整个主句。区别在于：as引导时意为“正如”，可位于句首或句中；而which 引导时意为“这
35、一点；这件事”，只能位于句中。as构成的固定表达：as is known to allas we all knowas is often the caseas isexpectedas is often saidas is reportedas is hopedasis stressed（4）定语从句中“介词关系代词”的用法：做介词的宾语的关系代词一般是which和 whom。“介词which/whom”既可以引导限制性定语从句，又可以引导非限制性定语从句。常见的有以下几种结构： 介词关系代词Mandela was the black lawyer to whom I went for adv
36、ice.Mandela was the black lawyer whom I went to for advice.曼德拉是我向其征求建议的一位黑人律师。I still remember the day on which we had a big party.我仍然记得我们举行一场盛大聚会的那一天。注意：介词的选择与先行词或者从句的谓语动词有关。把先行词放到从句里写出一个完整的句子，然后再将先行词换成对应的关系代词。固定短语中的介词不能提到关系代词的前面。如：He is the man that/whom your mother took care of last month. 他是你母亲上
37、个月照顾的那个人。 名词/代词/数词介词关系代词Last Sunday I bought some books from the bookstore,three of which were English novels.Last Sunday I bought some books from the bookstore,of which three were English novels.上个星期天，我从书店买回几本书，其中3本是英文小说。 形容词最高级介词关系代词。如：China has thousands of islands,the largest of which isTaiwan.中
38、国有成千上万的岛屿，其中最大的是台湾。（5）定语从句中whose的用法： whose既可以指人，又可指物，在定语从句中做定语，表示“人的；物的”。如：The room whose window faces south is mine. 窗户朝南的那个房间是我的。 whose指物时可用 of which 代替，但语序不同，即“whose名词”相当于“the名词of which”或“of whichthe名词”。如：The classroom whose door is broken will soon be repaired.The classroom the door of which is
39、broken will soon be repaired.The classroom of which the door is broken will soon be repaired.门坏了的那间教室将很快得到修缮。3.关系副词的用法当先行词是表时间、地点、方式或原因等的词，且从句缺状语时，从句用关系副词引导。关系副词有时可转化为“介词关系代词”。如：This is the place where we spent our childhood. 这里是我们度过童年的地方。注意：（1）当先行词是表时间、地点、方式、原因等的词时，只有在从句缺状语时才用关系副词引导；否则，用关系代词引导。如：He
40、ll always remember the day when his grandmother passed away. 他会永远记住他的奶奶去世的那一天。I will always remember the day that/ which we spent together in the countryside. 我会永远记住我们在乡下一起度过的那一天。This is the factory where my father once worked. 这是我父亲曾经工作过的工厂。This is the factory that/which they showed us around lasty
41、ear. 这是去年他们领我们参观的工厂。This is the reason why/for which he was late this morning.这是他今天早上迟到的原因。This is the reason that/which may explain his absence. 这是可以解释他缺席的理由。（2）先行词为 point,situation,case,stage,position,degree等表抽象的地点和情况的名词时，其后常用where引导定语从句，where在定语从句中做地点状语。而occasion 作“时机”讲时用when引导；作“场合”讲时用where引导。如：
42、Today,we will discuss a number of cases where Englishbeginners fail to use the languageproperly. 今天，我们将讨论一些英语初学者使用语言不当的例子。I can remember very few occasions when he had to cancel because of ill health. 我记得他因为健康不佳而被迫取消的情况绝无仅有。（3）先行词是the way（方式、方法），且引导词在定语从句中做状语时可以用in which或that引导从句，也可以省略引导词。如：The way
43、(that/ in which) he explained the sentence to us was not difficult to understand. 他解释这个句子的方式并不难懂。练习：1. The meeting room is crowded with children _ have poor eyesight, all of them interested in painting.2. Tango is a passionate dance, _ brings the dancers together in a way that words cant express.3.
44、Im taking some weight-loss pills, _ are quite popular here. 4. It was the largest map _ I had ever seen.5. Mr Zhang had a lot of friends, none of _ could lend him any money.6. _ was announced in the newspaper, our country won 51 gold medals in the 29th Olympic Games.7. Which was the very hotel _ was
45、 recommendedto you?8. Great changes have taken place since then in the factory _ we are working.9. Is there anyone in your class_ family is in thecountry?10. I can never forget the days _ we worked together and the time _ we spent together. (Answers:1. who/ that 2. which 3. which 4. that 5. whom6. A
46、s 7. that 8. where 9. whose 10. when; that/ which)四、Summary 重点词汇：blame, occur, survival, die out,depend on, at risk重点句型：关系副词where引导的定语从句；关系副词when 引导的定语从句；关系代词 which 引导的定语从句；“介词关系代词”引导的定语从句；关系副词why 引导的定语从句；含蓄虚拟条件句重点语法：定语从句五、HomeworkWrite a short passage to express solutions for environmental problems.