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Unit 4 Astronomy: the science of the stars
单元要览
类别
课程标准要求掌握的项目
话题
Science of the stars; the development of life; space travel and gravity
词汇]
astronomy
n. 天文学
exist
vi. 存在; 生存
system
n. 系统; 体系; 制度
thus
adv. 因此; 于是
religion
n. 宗教; 宗教信仰
dioxide
n. 二氧化物
theory
n. 学说; 理论
biology
n. 生物学
atom
n. 原子
biologist
n. 生物学家
billion
pron. & n. & adj. （英）万亿; （美）十亿
puzzle
n. 迷; 难题 vt. & vi. （使）迷惑; （使）为难
globe
n. 球体; 地球仪; 地球
gravity
n. 万有引力; 重力
violent
adj. 猛烈的; 激烈的; 强暴的
float
vt. & vi. （使）浮动; （使）漂浮 n. 漂浮物
carbon
n. 碳
gentle
adj. 温和的; 文雅的
atmosphere
n. 大气层; 气氛
physicist
n. 物理学家
unlike
prep. 不同; 不像
climate
n. 气候
fundamental
adj. 基本的; 基础的
crash
vt. & vi. 碰撞; 坠落
harmful
adj. 有害的
spaceship
n. 宇宙飞船
acid
n. 酸
pull
n. & vt. 拉; 拖; 牵引力
chain
n. 链子; 连锁; 锁链
satellite
n. 卫星; 人造卫星
multiply
vt. & vi. 乘; 增加
mass
n. 质量; 团; 块; 大量
oxygen
n. 氧
exhaust
vt. 用尽; 耗尽
短语
solar system太阳系
block out挡住（光线）
in time及时; 终于
cheer up感到高兴; 感到振奋
lay eggs下蛋
now that既然
give birth to产生; 分娩
break out突发; 爆发
in one’s turn轮到某人; 接着
watch out密切注视; 当心; 提防
carbon dioxide二氧化碳
prevent. . . from阻止; 制止
重要句型
1. What it was to become was uncertain until between 4. 5 and 3. 8 bill ion years ago when the dust settled into a solid globe. (be to do; what-clause as the subject)
2. The earth became so violent that it was not clear whether the shape would last or not. (so. . . that; it is/was not+adj. +whether-clause)
3. What is even more important is that as the earth cooled down, water began to appear on its surface. (what-clause as the subject; that-clause as the predicative)
4. It was not immediately obvious that water was to be fundamental to the development of life. /[it is/was (not)+adj. +that /]
5. So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved. (whether-clause as the subject; depend on+whether-clause as the object)
功能
Instructions:
Please pay attention to. . . Please check that. . . . You need. . .
Don’t forget to. . . Make sure that. . . . Watch out for. . .
You’d better. . . You must/mustn’t. . . Please look at. . .
语法
Noun clauses as the subject
What it was to become was uncertain. . .
. . . it was not clear whether the solid shape was to last or not.
教学重点
1. Get students to learn about the development of the earth and making a space trip.
2. Have students learn some useful new words and expressions and let them learn effective ways to remember English vocabulary.
3. Enable students to use the expressions of instructions correctly in daily life.
4. Let students learn the new grammar item: noun clauses as the subject.
5. Develop students’ listening, speaking, reading and writing abilities.
教学难点
1. Enable students to master the use of noun clauses as the subject.
2. Let students learn to write a short article to show their problems and the ways to overcome them.
3. Develop students’ integrative skills.
课时安排
Periods needed: 7
Period 1 Warming up and reading
Period 2 Learning about language: Important language points
Period 3 Learning about language: Grammar
Period 4 Using language: Listening and speaking
Period 5 Using language: Extensive reading
Period 6 Using language: Speaking and writing
Period 7 Revision: Summing up and learning tip
Period 1 Warming up and reading
整体设计
教材分析
This is the first teaching period of this unit. At the beginning of the class, the teacher can lead in the topic of the unit by having a free talk with students about some famous scientists and what they have discovered. Then turn to Warming Up. It is intended to have students think about and then discuss these two groups of questions:
1. In our solar system eight planets circle around the sun. What are they? Can you match the names with the planets?
2. What interests you in astronomy? Do you know any questions that astronomers are interested in?
Pre-reading is to remind students that the origin of life on the earth is a question that interests astronomers and each religion and culture has its own ideas about how life began on the earth. The teacher should ask students what they know about these and then let them predict what kind of information will be introduced in the next part Reading.
The reading passage titled HOW LIFE BEGAN ON THE EARTH provides students a brief introduction on how the universe developed and how life began on the earth. It provides a scientific background to any investigation into space and it is factual. Students are encouraged to preview the text and find out the useful new words, expressions and structures themselves. They should try to work out the meanings of the new words through the context. Then if necessary, they can look them up in the dictionary or turn to the teacher for help. Also encourage them to look at the pictures and read the title to guess what the text might be about. Then let them skim for the general idea, and scan for further understanding. In order not to let them feel much difficult, the teacher should deal with any language problems while they are reading. After reading, students are required to do the five exercises in the Comprehending to see how much they have understood the reading passage. The teacher can first let them work in pairs or in groups to find the answers cooperatively, and then check their answers with the whole class.
To consolidate the contents of the reading passage, students should be required to retell the passage. In order to arouse the students’ interest, the teacher can hold a competition.
教学重点
1. Let students read the passage and learn about the development of the earth.
2. Get students to learn different reading skills, especially the reading ability of understanding implied meaning of the author.
教学难点
1. Enable students to understand the passage and know about the development of the earth.
2. Let students learn how to use different reading skills for different reading purposes.
三维目标
知识目标
1. Get students to learn the useful new words and expressions in this part: astronomy, system, religion, theory, atom, billion, globe, violent, carbon, atmosphere, unlike, fundamental, harmf ul, acid, chain, multiply, oxygen, exist, thus, dioxide, puzzle, solar system, in time, lay eggs, give birth to, in one’s turn, carbon dioxide, prevent. . . from
2. Let students learn about the development of the earth.
能力目标
1. Develop students’ reading ability and let them learn different reading skills.
2. Enable students to know about the developmen t of the earth.
情感目标
1. Train students’ interest in science and stimulate their love for astronomy.
2. Develop students’ sense of cooperative learning.
教学过程
设计方案（一）
→Step 1 Presentation
Have a free talk with students.
1. Let students brainstorm the following questions:
Who are our ancestors?
Do you know what it was like before life appeared on the earth?
Do you know how life began on the earth?
Do you want to get more information?
2. Tell students:
Today we will learn something about how life began on the earth. Turn to Page 25. Let’s come to Warming Up first.
→Step 2 Warming up
Let st udents think about the following questions and then discuss them with their partners.
1. In our solar system eight planets circle around the sun. What are they? Can you match the names with the planets?
Venus
Earth
Mars
Mercury
Jupiter
Neptune
Saturn
2. What interests you in astronomy? Do you know any questions that astronomers are interested in?
→Step 3 Pre-reading
1. Get students to discuss the questions with their partners.
1) The origin of life on earth is a question that interests astronomers. What do you know about it?
2) Each religion and culture has its own ideas about how life began on earth. What do you know about them?
2. Let them tell their stories. Encourage them to tell different stories. If they don’t know any, tell them some, for example, Pangu separated the sky from the earth, Pangu turned into a myriad of things, Nuwa made men, and so on.
3. Ask them to read the title and look at the pictures. Predict what the reading will be about.
→Step 4 Reading
1. Fast reading
Get students to read the passage quickly and then write down the main idea for each paragraph and the whole passage in the following chart.
HOW LIFE BEGAN ON THE EARTH
Paragraph 1
Paragraph 2
Paragraph 3
Paragraph 4
Paragraph 5
The passage
Let students look through the chart and then read the text silently. Three minutes later, check the answers with the whole class.
2. Intensive reading
Allow students to read the passage carefully this time to get the important details, and then finish the following:
1) Put the order of development of life into a timeline.
(1) Insects and amphibians appeared.
(2) Dinosaurs appeared.
(3) The earth became a solid ball.
(4) Small plants grow on the water.
(5) Reptiles appeared.
(6) Plants begin to grow on dry land.
(7) The earth was a cloud of dust.
(8) Water appeared on the earth.
(9) Shellfish and other fish appeared.
(10) The universe began with a “Big Bang”.
(11) Clever animals with hands and feet appeared.
(12) Mammals appeared.
2) Choose the best answer to each question according to the text.
(1) What is important for the beginning of life?
A. The water on the earth.
B. The earth’s atmosphere.
C. The form of forests.
D. Dissolving harmful gases.
(2) Which of the following appeared on the earth first?
A. Insects.
B. Reptiles.
C. Amphibians.
D. Shellfish and fish.
(3) Which of the following statements is true?
A. Water still exists on Mars.
B. The earth’s atmosphere is made up of oxygen and nitrogen.
C. The earth had dissolved the harmful atmosphere into the oceans and seas.
D. Plants provide oxygen to the earth.
(4) What is the passage mainly about?
A. The appearance and development of life on the earth.
B. The birth of the earth.
C. Why dinosaurs died out.
D. The fact that human beings caused global warming.
Suggested answers: (1)A (2)D (3)D (4)A
3. Reading and discussion
Read the text a third time and then work in pairs to discuss the following questions.
1) Why was the earth different from the other planets?
2) Why did the plants grow before the animals came?
3) Why is it wrong to show films with dinosaurs and people together?
4) There used to be nine planets in the solar system. Recently scientists have decided that one of them can no longer be considered a planet. Do you know the name of that planet? Do you know why they removed it?
5) What problem is caused by human beings?
(Let students have enough time to read the passage carefully and discuss the questions with their partners. Encourage them to express their own idea s. )
4. Explanation
Help students analyze some difficult, long and complex sentences and guess the meaning of some new words. Encourage them to try to deal with the language points in the context.
Discuss the following important sentences and phrases in the passage.
1) What it was to become was uncertain until between 4. 5 and 3. 8 billion years ago when the dust settled into a solid globe.
2) The earth became so violent that it was not clear whether the shape would last or not.
3) They were in time to produce carbon, nitrogen, water vapor and other gases, which were to make the earth’s atmosphere.
4) So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.
Suggested explanations:
1) What leads a noun clause as the subject and when leads an attributive clause.
2) Here “whether the shape would last or not” is a noun clause as the subject.
3) Here “which were to make the earth’s atmosphere” is a non-restrictive attributive clause.
in time: 1) sooner or later; eventually 2) in time (for sth. /to do sth. ): not late
I will see him in time.
She will be back in time to prepare dinner.
4) In this sentence, there are two clauses led by whether. The first one is a noun clause as the subject and the second as the object.
to come: serves as attributive
She is the last person to do such a thing.
depend on: something might only happen or be true if the circumstances are right for it
Our success depends on whether everyone works hard or not.
5. Reading aloud and underlining
Ask students to read the passage aloud to the tape and let them pay attention to the pronunciation of each new word and the pauses within each sentence. Tell them to pick out all the useful expressions or collocations from the passage while reading and copy them to the notebooks after class as homework.
Collocations: on the earth, according to, a cloud of dust, so. . . that, whether. . . or not, in time, water vapor, cool down, on one’s surface, allow. . . to do. . . , a chain reaction, millions of, on the surface of, be able to, as well as, by doing. . . . , lay eggs, be different from, give birth to, spread all over the earth, in one’s turn, prevent. . . from, as a r esult of, too. . . to. . . , depend on
→Step 5 Discussion
After reading the passage, let students discuss the following questions.
1. Why do you think that humans are the cleverest animals on the earth?
2. Do you believe that there is life on other planets? Why or why not?
3. Do you think it is possible that one day people will move their houses to other planets?
→Step 6 Consolidation
Ask students to retell the passage with the help of the following.
a cloud of dust→a solid ball→presence of water→small plants grow on the water→shellfish and other fish appear→plants begin to grow on dry land→insects and amphibians appear→retiles appear→dinosaurs appear→mammals appear
→Step 7 Homework
1. Learn the useful new words and expressions in this part by heart.
2. Read the reading passage again and try to talk about how life began on the earth in your own words.
设计方案（二）
→Step 1 Leading in the topic
Show students a picture about solar system. Let them match the names with the planets.
→Step 2 Warming up
Each religion and culture has its own ideas about the origin of life on the earth. Let students tell different stories that they know.
→Step 3 Predicting by looking and discussing
1. Look at the pictures and title of the reading passage and discuss in pairs what the passage might be about.
2. Two or three students will give their opinions.
3. Let them read the passage quickly to see if they are right.
→Step 4 Reading
1. Give students 3 minutes, an d ask them to skim the passage to get the general idea for each paragraph and the p assage.
2. Give students 5 minutes to read the passage carefully, and then answer the following questions.
1) What was there on the earth before life began?
2) Why do sci entists think there has never been life on the moon?
3) Why did animals first appear in the sea?
4) Why do green plants help life to develop?
5) Why were mammals different from other animals?
3. Give students 4 minutes to read the passage a third time. Encourage them to try to deal with the language points in the context. Give them some explanations if necessary.
4. Listening and reading aloud
Let students listen to the tape. Remind them to pay attention to the pronunciation of each new word and the pauses within each sentence. Then ask them to read the text aloud to the tape.
→Step 5 Extension
Let students think about and discuss the following questions.
1. Do you believe that there is life on other planets? Why or why not?
2. Do you think it is possible that one day people will move their houses to other planets?
→Step 6 Closing down
1. Have students get prepared in 3 minutes or so and then ask them to retell how life began on the earth.
2. Ask as many students as possible to have a try in front of the class.
→Step 8 Homework
1. Go over the text and try to learn all the useful words and expressions in this part by heart.
2. Finish the exercises in Comprehending on Page 27.
板书设计
Unit 4 Astronomy: the science of the stars
Warming up and reading
HOW LIFE BEGAN ON THE EARTH
Paragraph 1
Paragraph 2
Paragraph 3
Paragraph 4
Paragraph 5
The passage
活动与探究
Suppose you are an expert who studies astronomy. You are invited to give a speech to the school students about the development of life on Earth Day (April 22).
Read the passage HOW LIFE BEGAN ON THE EARTH again and go to the library or surf the Internet to find more information and be ready to present your speech to the class.
You may begin like this:
Good morning/afternoon. I am greatly honored to be here to give you a speech about the development of life.
Unit 4 Astronomy: the science of the stars
单元要览
类别
课程标准要求掌握的项目
话题
Science of the stars; the development of life; space travel and gravity
词汇]
astronomy
n. 天文学
exist
vi. 存在; 生存
system
n. 系统; 体系; 制度
thus
adv. 因此; 于是
religion
n. 宗教; 宗教信仰
dioxide
n. 二氧化物
theory
n. 学说; 理论
biology
n. 生物学
atom
n. 原子
biologist
n. 生物学家
billion
pron. & n. & adj. （英）万亿; （美）十亿
puzzle
n. 迷; 难题 vt. & vi. （使）迷惑; （使）为难
globe
n. 球体; 地球仪; 地球
gravity
n. 万有引力; 重力
violent
adj. 猛烈的; 激烈的; 强暴的
float
vt. & vi. （使）浮动; （使）漂浮 n. 漂浮物
carbon
n. 碳
gentle
adj. 温和的; 文雅的
atmosphere
n. 大气层; 气氛
physicist
n. 物理学家
unlike
prep. 不同; 不像
climate
n. 气候
fundamental
adj. 基本的; 基础的
crash
vt. & vi. 碰撞; 坠落
harmful
adj. 有害的
spaceship
n. 宇宙飞船
acid
n. 酸
pull
n. & vt. 拉; 拖; 牵引力
chain
n. 链子; 连锁; 锁链
satellite
n. 卫星; 人造卫星
multiply
vt. & vi. 乘; 增加
mass
n. 质量; 团; 块; 大量
oxygen
n. 氧
exhaust
vt. 用尽; 耗尽
短语
solar system太阳系
block out挡住（光线）
in time及时; 终于
cheer up感到高兴; 感到振奋
lay eggs下蛋
now that既然
give birth to产生; 分娩
break out突发; 爆发
in one’s turn轮到某人; 接着
watch out密切注视; 当心; 提防
carbon dioxide二氧化碳
prevent. . . from阻止; 制止
重要句型
1. What it was to become was uncertain until between 4. 5 and 3. 8 bill ion years ago when the dust settled into a solid globe. (be to do; what-clause as the subject)
2. The earth became so violent that it was not clear whether the shape would last or not. (so. . . that; it is/was not+adj. +whether-clause)
3. What is even more important is that as the earth cooled down, water began to appear on its surface. (what-clause as the subject; that-clause as the predicative)
4. It was not immediately obvious that water was to be fundamental to the development of life. /[it is/was (not)+adj. +that /]
5. So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved. (whether-clause as the subject; depend on+whether-clause as the object)
功能
Instructions:
Please pay attention to. . . Please check that. . . . You need. . .
Don’t forget to. . . Make sure that. . . . Watch out for. . .
You’d better. . . You must/mustn’t. . . Please look at. . .
语法
Noun clauses as the subject
What it was to become was uncertain. . .
. . . it was not clear whether the solid shape was to last or not.
教学重点
1. Get students to learn about the development of the earth and making a space trip.
2. Have students learn some useful new words and expressions and let them learn effective ways to remember English vocabulary.
3. Enable students to use the expressions of instructions correctly in daily life.
4. Let students learn the new grammar item: noun clauses as the subject.
5. Develop students’ listening, speaking, reading and writing abilities.
教学难点
1. Enable students to master the use of noun clauses as the subject.
2. Let students learn to write a short article to show their problems and the ways to overcome them.
3. Develop students’ integrative skills.
课时安排
Periods needed: 7
Period 1 Warming up and reading
Period 2 Learning about language: Important language points
Period 3 Learning about language: Grammar
Period 4 Using language: Listening and speaking
Period 5 Using language: Extensive reading
Period 6 Using language: Speaking and writing
Period 7 Revision: Summing up and learning tip
Period 1 Warming up and reading
整体设计
教材分析
This is the first teaching period of this unit. At the beginning of the class, the teacher can lead in the topic of the unit by having a free talk with students about some famous scientists and what they have discovered. Then turn to Warming Up. It is intended to have students think about and then discuss these two groups of questions:
1. In our solar system eight planets circle around the sun. What are they? Can you match the names with the planets?
2. What interests you in astronomy? Do you know any questions that astronomers are interested in?
Pre-reading is to remind students that the origin of life on the earth is a question that interests astronomers and each religion and culture has its own ideas about how life began on the earth. The teacher should ask students what they know about these and then let them predict what kind of information will be introduced in the next part Reading.
The reading passage titled HOW LIFE BEGAN ON THE EARTH provides students a brief introduction on how the universe developed and how life began on the earth. It provides a scientific background to any investigation into space and it is factual. Students are encouraged to preview the text and find out the useful new words, expressions and structures themselves. They should try to work out the meanings of the new words through the context. Then if necessary, they can look them up in the dictionary or turn to the teacher for help. Also encourage them to look at the pictures and read the title to guess what the text might be about. Then let them skim for the general idea, and scan for further understanding. In order not to let them feel much difficult, the teacher should deal with any language problems while they are reading. After reading, students are required to do the five exercises in the Comprehending to see how much they have understood the reading passage. The teacher can first let them work in pairs or in groups to find the answers cooperatively, and then check their answers with the whole class.
To consolidate the contents of the reading passage, students should be required to retell the passage. In order to arouse the students’ interest, the teacher can hold a competition.
教学重点
1. Let students read the passage and learn about the development of the earth.
2. Get students to learn different reading skills, especially the reading ability of understanding implied meaning of the author.
教学难点
1. Enable students to understand the passage and know about the development of the earth.
2. Let students learn how to use different reading skills for different reading purposes.
三维目标
知识目标
1. Get students to learn the useful new words and expressions in this part: astronomy, system, religion, theory, atom, billion, globe, violent, carbon, atmosphere, unlike, fundamental, harmf ul, acid, chain, multiply, oxygen, exist, thus, dioxide, puzzle, solar system, in time, lay eggs, give birth to, in one’s turn, carbon dioxide, prevent. . . from
2. Let students learn about the development of the earth.
能力目标
1. Develop students’ reading ability and let them learn different reading skills.
2. Enable students to know about the developmen t of the earth.
情感目标
1. Train students’ interest in science and stimulate their love for astronomy.
2. Develop students’ sense of cooperative learning.
教学过程
设计方案（一）
→Step 1 Presentation
Have a free talk with students.
1. Let students brainstorm the following questions:
Who are our ancestors?
Do you know what it was like before life appeared on the earth?
Do you know how life began on the earth?
Do you want to get more information?
2. Tell students:
Today we will learn something about how life began on the earth. Turn to Page 25. Let’s come to Warming Up first.
→Step 2 Warming up
Let st udents think about the following questions and then discuss them with their partners.
1. In our solar system eight planets circle around the sun. What are they? Can you match the names with the planets?
Venus
Earth
Mars
Mercury
Jupiter
Neptune
Saturn
2. What interests you in astronomy? Do you know any questions that astronomers are interested in?
→Step 3 Pre-reading
1. Get students to discuss the questions with their partners.
1) The origin of life on earth is a question that interests astronomers. What do you know about it?
2) Each religion and culture has its own ideas about how life began on earth. What do you know about them?
2. Let them tell their stories. Encourage them to tell different stories. If they don’t know any, tell them some, for example, Pangu separated the sky from the earth, Pangu turned into a myriad of things, Nuwa made men, and so on.
3. Ask them to read the title and look at the pictures. Predict what the reading will be about.
→Step 4 Reading
1. Fast reading
Get students to read the passage quickly and then write down the main idea for each paragraph and the whole passage in the following chart.
HOW LIFE BEGAN ON THE EARTH
Paragraph 1
Paragraph 2
Paragraph 3
Paragraph 4
Paragraph 5
The passage
Let students look through the chart and then read the text silently. Three minutes later, check the answers with the whole class.
2. Intensive reading
Allow students to read the passage carefully this time to get the important details, and then finish the following:
1) Put the order of development of life into a timeline.
(1) Insects and amphibians appeared.
(2) Dinosaurs appeared.
(3) The earth became a solid ball.
(4) Small plants grow on the water.
(5) Reptiles appeared.
(6) Plants begin to grow on dry land.
(7) The earth was a cloud of dust.
(8) Water appeared on the earth.
(9) Shellfish and other fish appeared.
(10) The universe began with a “Big Bang”.
(11) Clever animals with hands and feet appeared.
(12) Mammals appeared.
2) Choose the best answer to each question according to the text.
(1) What is important for the beginning of life?
A. The water on the earth.
B. The earth’s atmosphere.
C. The form of forests.
D. Dissolving harmful gases.
(2) Which of the following appeared on the earth first?
A. Insects.
B. Reptiles.
C. Amphibians.
D. Shellfish and fish.
(3) Which of the following statements is true?
A. Water still exists on Mars.
B. The earth’s atmosphere is made up of oxygen and nitrogen.
C. The earth had dissolved the harmful atmosphere into the oceans and seas.
D. Plants provide oxygen to the earth.
(4) What is the passage mainly about?
A. The appearance and development of life on the earth.
B. The birth of the earth.
C. Why dinosaurs died out.
D. The fact that human beings caused global warming.
Suggested answers: (1)A (2)D (3)D (4)A
3. Reading and discussion
Read the text a third time and then work in pairs to discuss the following questions.
1) Why was the earth different from the other planets?
2) Why did the plants grow before the animals came?
3) Why is it wrong to show films with dinosaurs and people together?
4) There used to be nine planets in the solar system. Recently scientists have decided that one of them can no longer be considered a planet. Do you know the name of that planet? Do you know why they removed it?
5) What problem is caused by human beings?
(Let students have enough time to read the passage carefully and discuss the questions with their partners. Encourage them to express their own idea s. )
4. Explanation
Help students analyze some difficult, long and complex sentences and guess the meaning of some new words. Encourage them to try to deal with the language points in the context.
Discuss the following important sentences and phrases in the passage.
1) What it was to become was uncertain until between 4. 5 and 3. 8 billion years ago when the dust settled into a solid globe.
2) The earth became so violent that it was not clear whether the shape would last or not.
3) They were in time to produce carbon, nitrogen, water vapor and other gases, which were to make the earth’s atmosphere.
4) So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.
Suggested explanations:
1) What leads a noun clause as the subject and when leads an attributive clause.
2) Here “whether the shape would last or not” is a noun clause as the subject.
3) Here “which were to make the earth’s atmosphere” is a non-restrictive attributive clause.
in time: 1) sooner or later; eventually 2) in time (for sth. /to do sth. ): not late
I will see him in time.
She will be back in time to prepare dinner.
4) In this sentence, there are two clauses led by whether. The first one is a noun clause as the subject and the second as the object.
to come: serves as attributive
She is the last person to do such a thing.
depend on: something might only happen or be true if the circumstances are right for it
Our success depends on whether everyone works hard or not.
5. Reading aloud and underlining
Ask students to read the passage aloud to the tape and let them pay attention to the pronunciation of each new word and the pauses within each sentence. Tell them to pick out all the useful expressions or collocations from the passage while reading and copy them to the notebooks after class as homework.
Collocations: on the earth, according to, a cloud of dust, so. . . that, whether. . . or not, in time, water vapor, cool down, on one’s surface, allow. . . to do. . . , a chain reaction, millions of, on the surface of, be able to, as well as, by doing. . . . , lay eggs, be different from, give birth to, spread all over the earth, in one’s turn, prevent. . . from, as a r esult of, too. . . to. . . , depend on
→Step 5 Discussion
After reading the passage, let students discuss the following questions.
1. Why do you think that humans are the cleverest animals on the earth?
2. Do you believe that there is life on other planets? Why or why not?
3. Do you think it is possible that one day people will move their houses to other planets?
→Step 6 Consolidation
Ask students to retell the passage with the help of the following.
a cloud of dust→a solid ball→presence of water→small plants grow on the water→shellfish and other fish appear→plants begin to grow on dry land→insects and amphibians appear→retiles appear→dinosaurs appear→mammals appear
→Step 7 Homework
1. Learn the useful new words and expressions in this part by heart.
2. Read the reading passage again and try to talk about how life began on the earth in your own words.
设计方案（二）
→Step 1 Leading in the topic
Show students a picture about solar system. Let them match the names with the planets.
→Step 2 Warming up
Each religion and culture has its own ideas about the origin of life on the earth. Let students tell different stories that they know.
→Step 3 Predicting by looking and discussing
1. Look at the pictures and title of the reading passage and discuss in pairs what the passage might be about.
2. Two or three students will give their opinions.
3. Let them read the passage quickly to see if they are right.
→Step 4 Reading
1. Give students 3 minutes, an d ask them to skim the passage to get the general idea for each paragraph and the p assage.
2. Give students 5 minutes to read the passage carefully, and then answer the following questions.
1) What was there on the earth before life began?
2) Why do sci entists think there has never been life on the moon?
3) Why did animals first appear in the sea?
4) Why do green plants help life to develop?
5) Why were mammals different from other animals?
3. Give students 4 minutes to read the passage a third time. Encourage them to try to deal with the language points in the context. Give them some explanations if necessary.
4. Listening and reading aloud
Let students listen to the tape. Remind them to pay attention to the pronunciation of each new word and the pauses within each sentence. Then ask them to read the text aloud to the tape.
→Step 5 Extension
Let students think about and discuss the following questions.
1. Do you believe that there is life on other planets? Why or why not?
2. Do you think it is possible that one day people will move their houses to other planets?
→Step 6 Closing down
1. Have students get prepared in 3 minutes or so and then ask them to retell how life began on the earth.
2. Ask as many students as possible to have a try in front of the class.
→Step 8 Homework
1. Go over the text and try to learn all the useful words and expressions in this part by heart.
2. Finish the exercises in Comprehending on Page 27.
板书设计
Unit 4 Astronomy: the science of the stars
Warming up and reading
HOW LIFE BEGAN ON THE EARTH
Paragraph 1
Paragraph 2
Paragraph 3
Paragraph 4
Paragraph 5
The passage
活动与探究
Suppose you are an expert who studies astronomy. You are invited to give a speech to the school students about the development of life on Earth Day (April 22).
Read the passage HOW LIFE BEGAN ON THE EARTH again and go to the library or surf the Internet to find more information and be ready to present your speech to the class.
You may begin like this:
Good morning/afternoon. I am greatly honored to be here to give you a speech about the development of life.
