新人教版高中英语必修三Unit 4《Astronomythe science of the stars》精品学案

1、新人教版高中英语必修三unit 4astronomy:the science of the stars精品学案teaching aims：1.knowledge aim：to grasp some important words and phrases.in time, mulply, lay eggs, depend on , preventfrom2.ability aim:sharing your ideas with your classmates bravely;talking about the difficult points with your group-mates hear

2、tedly;practisng the language points actively.3.emotional aim:to make students know the importance of protecting the environment.teaching important points:to grasp some important words and phrases;to grasp the usage of the subject clause.teaching difficult points:to grasp the usage of the subject cla

3、use.teaching methods:double activities teaching method;group discussion method;pair work or individual work method.teaching aids:multimedia; the blackboard.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 expl

4、oded 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 _on land .when the plants grew into forests,reptiles appea

5、red for the first time. they produced young generally by _eggs. when dinosaurs disappeared, mammals became more important. now small clever animals with hands and feet appeared and spread all over the world. as time went by they covered the earth and they are putting too much carbon dioxide into the

6、 atmosphere,which _heat _the earth into space. whether life will continue on earth for millions of years to come will_whether this problem can be solved.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 eart

7、hs atmosphere.【归纳】in time: sooner or later; eventually 迟早；最后总有一天我会遇见他。ill see him in time. in time (for sth/to do sth): not late 及时；不迟【即境活用】she will be back _to prepare dinner. (她来得及回来准备晚饭).2.multiply.【原文再现】they multiplied and filled the oceans and sea with oxygen,which encouraged the later developm

8、ent of early shellfish and all sorts of fish.1)2 multiplied by 4 makes 8.2)our problems have multiplied since last year.3)rabbits here multiply rapidly.【归纳】 multiply v. 有三种意思:1)_;2)_3)_.multiplicity n.有多种类型. 【拓展】add vt. 加上 minus vt. 减,减去 divide vt. 除,除法【即境活用】the childern are learning to _(乘法)and _.(

9、除法)3. lay eggs. 【原文再现】they produced young generally by laying eggs.【归纳】lay-laid-laid-laying 放, 把. 放在.; 产卵 【拓展】lay (laid; laid; laying) 放置;产卵 lie (lay; lain; lying) 躺;位于 lie (lied; lied; lying) 说谎 口诀:规则撒谎，不规则躺，躺过去产蛋，产蛋不规则。（躺的过去式是lay）【即境活用】he_ on the desk.(他把他的书放在桌子上)【高考链接】the naughty boy _ to me that

10、 the hen that _ there just now had_ two eggs the day before. a. laid; laid; laid b. laid; lay; lain c. lied; laid; lain d. lied; lay; laid4. preventfrom.【原文再现】they are putting too much carbon dioxide into the atmosphere, which prevents heat from escaping from the earth into space.句子分析：这是一个由 _引导的_ 修饰

11、前面整个句子,关系代词which在从句中作_.【归纳】prevent sth. / sb. (from) doing sth. 制止(防止)某人(某物)做某事; 这种含义常用相关短语: _;_.【拓展】protect sb. from doing_; defendfrom_【即境活用】1)his heart trouble did not _going to class the next day.2)nothing can prevent this plan_. (carry out)5. depend on 【原文再现】 whether life will continue on the e

12、arth for millions of years to come will depend on whether this problem can be solved. 【归纳】(sth) depend on (sth else): 取决于; 我们的成败取决于是否每个人都努力工作。our success _ whether everyone works hard or not.depend on sb. / sth; sb. to do sth; sb. doing sth; sb. /sth. for sth. 【拓展】相信，信赖, 依靠,依赖, 视而定，取决于 1)when you ar

13、e in a strange place youd better depend on the map. 2) he depends on his pen for his living. 3) you can depend on him. hell lead you there.depend on it 没问题，请放心（句末或句首） that /it (all) depends. 那得看情况而定 1) depend on it, youll succeed. 2) he may support me, but it depends . 【即境活用】高考链接-how long are you st

14、aying? - i dont know._.(04江苏) a.thats ok b.it depends c.never mind d.it doesnt matterstep3 discovering useful structures: the subject clause1.study the rule:1) what part does the underlined part serve as in each sentence? a. you are a student.b. smoking is bad for you.c. to find your way can be a pr

15、oblem.d. “how do you do?” is a greeting.e .what she said is not yet known.f. that we shall be late is certain.g. it is certain that we shall be late.2)find the sentences with the subject clauses from the reading passage in par.35.and underline them,then translate them into chinese.example:what many

16、scientists believe is that the continued presence of water para3._para4._para5._2. find the rule:一个句子在复合句中充当名词的作用,可以做主语、宾语、表语和同位语,这个句子就叫名词性从句.主语从句是在复合句中充当_的从句,通常放在主句谓语动词之前或由形式主语_代替,而本身放在句子末尾.1) a.用what / whether / that/ if/where / how / when /why /who / how much / etc. 来连接主语从句.b. 有时为了使句子结构平衡, 避免 “头重

17、脚轻”,常用it作形式主语,而把从句放在后面.c.引导主语从句在句首只能用_有it作形式主语的whether/if都可以.d._在主语从句中不能省略.2).在主语从句中，谓语一般用单数。无论他说什么都不重要。whatever he says is of no importance.但谓语动词用单数还是复数，不可一概而论，而要视句子的意义而定what i need _money. what i need _books.3. apply the rule: rewrite the sentences with noun clauses as the subject.for example: his

18、 discovery has not yet been proved.what has not yet been proved is his discovery. 1) do the other astronomers accept his ideas?it remains a question.whether_2) why is the earth becoming warmer?it is an important topic for research.why_step4【当堂小练】1.in fact, he _in bed all the morning without doing an

19、ything, but he _to me about that .a.lied;lied b.lay;lay c.lied; lay d. lay; lied 2.i dont believe that older people are always wiser. it _the person and what kind of experiences he or she has had.a.requires of b.results from c. belongs to d.depends on 3. (08山东23) was most important to her，she told m

20、e，was her family.a.it b.this c.as d. what4.(08福建27) is known to us all is that the 2008 olympic games will take place in beijing.a.it b.as c.which d. what5. villagers planted a lot of trees to_.(防止土壤被冲走)6. 起初,吉姆和汤姆不喜欢彼此,但最后他们成了好朋友.(in time)_step5 appreciating a short passage. how to protect the earth in the past, we human beings lived in harmony with nature. it was obvious that the environment was much better, so we enjoyed a comfortable life in time. h