（新人教版）高中英语必修三《Unit 4 Astronomythe science of the stars》精品课件.ppt

unit 4 astronomy: the science of the stars,learning about language,step1 revision: fill in the blanks according to the reading passage.,after the “big bang”, the earth was just a cloud of energetic dust. it exploded loudly with fire and rock, which were _to produce the water vapour, carbon dioxide and other gases. then small plants grew .they_and filled the oceans and seas with oxygen. many millions of years later the first green plants began to appear on land. when the plants grew into forests, reptiles appeared for the first time.,in time,multiplied,they produced young generally by_eggs. when dinosaurs _on the earth for more than 140 million years and disappeared, mammals became more important. now small clever animals with hands and feet appeared and spread all over the world. as time go by they covered the earth and they are putting too much carbon dioxide into the _, which _heat _ escaping from the earth into space. whether life will continue on earth for millions of years to come will depend on whether this problem can be solved.,laying,existed,atmosphere,prevents,from,step2 words and expressions,1.in time 【原文再现】they were in time to produce carbon, nitrogen, water vapour and other gases, which were to make the earths atmosphere. 句子分析：which were to make the earths atmosphere 是_成分, 指代_ 【归纳】in time 来得及；总有一天，迟早 例如:1)i was just in time for the flight. _ 2) i will see him in time _,定语从句,carbon,nitrogen,watervapour and other gases,我正好赶上航班,我迟早会见到他,【拓展】与time 有关的短语 in no time 立即，立刻 ; at any time 在任何时候; at one time 曾经,一度 ; at times 有时，偶尔 ; on time 按时，准时 ; of the time 现在的，当时的 【即学活用】1) if you keep on, youll succeed_. (93年全国卷i) a. in time b. at one time c. at the same time d. on time,2. multiply (1)【原文再现】they multiplied and filled the oceans and seas with oxygen, which encouraged the later shellfish and all sorts of fish. (2)using this method, youll find the efficiency is multiplied several times (3)7 multiplied by 8 is 56 【归纳】multiply的含义是：(1)_ (2)_ (3)_ 【即学活用】_9_3,and the product is 27.,繁殖,增多，增加,相乘,multiply,by,3. lay 【原文再现】they produced young generally by laying eggs 【拓展】 1) 放，置 lay it on the table ; 2) 摆放好to lay the table ; 3) 产，下（蛋）the hen laid three eggs 【辨析】,【即学活用】they _ us _ for three months. a .laid off _ b. laid down _ c. laid on _ d. laid out _,解雇,放下,安装,设计，花费,4.exist (1)【原文再现】they laid eggs too and existed on the earth for more than 140 million years. (2)the laid-off workers mainly exist on bread and tea. (3)this kind of trees only exists in china.,【归纳】 1). exist（ on sth）生存，活下来，幸存; 靠 为生 2).exist in sth 存在于之中3).existence n.存在 ; 生活. 【即学活用】 people do not now believe in the _of ghosts. a. birth b. evidence c. existence d. occurrence,5. atmosphere (1)【原文再现】 they are putting too much carbon dioxide into the atmosphere (2)the atmosphere changed as soon as she walked in. 【归纳】atmosphere 为名词，其含义1)_ 2)_其形容词atmospherictmsferk adj.大气的e.g. atmospheric pressure 大气压力。 【即学活用】 the top leaders of the two countries are holding talks in a friendly_（22湖北08） a. atmosphere b.state c.situationd.phenomenon,大气,气氛,6. prevent from 【原文再现】which prevent heat from escaping from the earth into space 【注意】prevent后面跟名词和代词作宾语，在宾语后可跟from doing，from可以省略。因此prevent sb（ from） doing 和prevent sb/sb doing 都可以。 【辨析】preventfrom ，stopfrom ，keepfrom 三者意思相近，常可互换，preventfrom和stopfrom用于主动语态时from可以省略，但用于被动语态时不可省略；keepfrom 中的from不能省略。,【即学活用】 nobody can stop me _the tennis match on my radio. a. to listen b. listening c. listen to d. listening to,step3 discovering useful words and expressions deal with “discovering useful words and expressions” of the textbook.,answers to “ discovering useful words and expressions”,ex.1:,ex.2: c;a;c;b.,ex.3:1.fundamental;2.astronomy;3.gives birth to; 4.existed; 5.as a result; 6.atoms; 7.prevents from; 8.puzzle,ex.4: emotional words: 1.violent; 2.angry; 3.rude; 4.shocked 5.excited; 6.crazy.,step4 discovering useful structures： noun clauses as the subject,1.study the rule: (1) what part does the underlined part serve as in each sentence of group 1 ? 1）a tree has fallen across the road. 2）you are a student. 3）to find your way can be a problem. 4）smoking is bad for you. the underlined part serves as_,subject,what part does the underlined part serve as in each sentence of group 2 ? 1)“how do you do?” is a greeting. 2) what she said is not yet known. 3)that we shall be late is certain. 4)it is certain that we shall be late. we can see from these sentences that a sentence serves as _, so we call it _.,subject,subject clause,(2) sentences- making practice it is certain. we will be late (that) e.g: it is certain that we will be late is she coming or not? we dont know.(whether) _ what does he want to tell us? we dont know. (what) _ when will you come back? it doesnt matter (when) _,we dont know whether she is coming or not,we dont know what he wants to tell us,when you will come back doesnt matter,2.find the rule (1) 在句子中起 名词作用的句子叫_, 名词性从句的功能相当于名词词组，在复合句中担任主语时就叫_ (2) 名词性从句的连接词可以分为三类: 连接词that, whether； 连接代词who, whoever, what, whatever,和which； 连接副词when, whenever , where, how和why,名词性从句,主语从句,（3）有时为了使句子结构平衡, 避免 “头重脚轻”, 常用 it 作形式主语, 而把从句放在后面。 例如: it is a pity that she has made such a mistake. (4) 用于it is important / natural / necessary / impossible that.句型中, 主语从句应使用虚拟语气, 谓语动词用“should + 动词原形”的形式, should有时有感情色彩。 (5) 两点注意：1）主语从句放句首时，必须有连接词引导，不能省略；如果it 作形式主语，而把主语从句放句末时，从属连词that 可以省略；2）主语从句放句首，不能用if 引导。,3. apply the rule: multiple choices 1. _ is known to us all is that the 2008 olympic games will take place in beijing. （福建卷） a. it b. what c. as d. which .2. _ was most important to her, she told me, was her family. （山东卷） it b. this c. what d. as,step5 当堂小练 一、finish the multiple choices we cant continue to pretend that the problem of homelessness doesnt _ in this city. a. exist b. live c. be d. survive 2. he wants to see changes in the company and i am sure he will, _. a. on time b. at a time c. at one time d. in time 3. _ anyone should want to kill her was unbelievable. a. whether b. that c. what d. if,4. they have put the bird in a cage to _it from flying away. a. avoid b. prevent c. let d. resist 5.兔子繁殖得很快（multiply） _ 6.一只躺在树下的公鸡撒谎说它生了一个蛋。 _,rabbits multiply rapidly,a cock lying under the tree lied to lay an egg,二、complete the following passage with words and phrases below in the correct form. is the moon a planet? debates about this question _ since it appeared. some scientists living in the _think that the earth gives birth to the moon because the moon circles our planet. others believe