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1、,Subject Clauses主语从句,豌豆语法-主语从句豌豆群：7298916,定义：用作主语的从句叫主语从句，它是名词 性从句之一。引导主语从句的连接词有：从属连词:that,whether；连接代词:who(whoever),whom,whose,what(whatever)和which(whichever)；连接副词:when,where,how和why。,1.连接词：,1）从属连词：that，whether 引导主语从句只起引导作用，在主语从句中不充当任何成分，that本身无实际意义，但不能省略.whether意为“是否”，放在句首句末皆可。,That price will go
2、up is certain.That he will come is certain.Whether we go by train or by boat makes no difference.Whetherhellcomehereisntclear.,2)连接代词 who(whoever),what(whatever),which(whichever),whom,whose.,Which side will win is not clear.Who will write the poem has not been decided yet.Whatever he did is right.Wh
3、o killed the scientist remains a question.Whom she borrowed money from still puzzled him.,3)连接副词when，where，how，why等。,Howthishappenedisnotcleartoanyone.When he will be back depends on the weather.When well start tomorrow will be told soon.Where the test will be given is not yet decided.,主语从句后置!为了避免主语
4、冗长,句子头重脚轻,经常用 it 作 形式主语,主语从句放在后面作真正的主语.例:That we shall be late is certain.-Its certain that we shall be late.1.That the earth is round is known to all.-2.That you missed the chance is a pity.-,It is a pity that you missed the chance.,Its known to all that the earth is round.,A.It is+形容词+从句It is nece
5、ssary that 有必要It is clear that 很清楚It is likely that 很可能It is important that 重要的是类似的形容词还有：strange;natural;obvious;true;good;wonderful;possible;unlikely;quite;unusual;certain;evident;worth-while;surprising;interesting;astonishing,etc.,2.用it 作形式主语的结构,例如：It is obvious that conductors and insulators are
6、both important in industry.It is doubtful whether she will be able to come.她是否能来令人怀疑。It was really astonishing that he refused to talk to you.他拒绝和你说话真是令人惊讶。It is essential that he should be here by the weekend.周末之前，他应该到这里是必要的。It seems obvious that we can not go on like this.很明显我们不能这样下去了。,B It is+名词+
7、从句It is a fact that 事实是It is good news that 是好消息It is a question that 是个问题It is common knowledge that 是常识类似的名词还有：a pity；a wonder；a good thing；no wonder；surprise等。例如：It is a mystery to me how it all happened.这一切是怎么发生的是个谜。It is common knowledge that the whale is not a fish.鲸鱼不是鱼，这是常识。It is no surprise
8、 that Bob should have won the game.鲍勃会赢得这场比赛，这不足为奇。,3）It is+过去分词+从句It is said that 据说It is reported that 据报道It has been proved that 已证明It must be proved that 必须指出类似的过去分词还有：known;estimated;expected;believed;thought;hoped;noted;discussed;required;decided;suggested;demanded;made clear;found out.例如：It i
9、s thought that he is the best player.大家都认为他是最好的选手。It is estimated that the vase is 2000 years old.据估计这个花瓶有2000年的历史。,D.It+不及物动词或短语+that 从句(seem，happen,doesntmatter,turn out）。如：IthappenedthatIwasoutthatday.Itdoesntmatterwhethershewillcomeornot.,3.主语从句不可位于句首的五种情况(1)if 引导的主语从句不可居于复合句句首。(2)It is said,(re
10、ported)结构中的主语从句不可提前。例如：It is said that Sun yang will visit our school next week.(3)It happens,It occurs 结构中的主语从句不可提前。例如：It occurred to him that he failed in the examination.,(4)It doesnt matter how/whether 结构中的主语从句不可提前。例如：It doesnt matter whether he is wrong or not.(5)含主语从句的复合句是疑问句时，主语从句不可提前。例如：Is i
11、t likely that it will rain in the evening?4.What 与that 在引导主语从句时的区别 What 引导主语从句时在从句中充当句子成分，如主语宾语表语，而that 则不然。例如：What you said yesterday is right.,4主语从句的时态：不受主句的时态影响和限制。（1）That he finished writing the composition in such a short time surprised us all.（2）Whether we will go for an outing tomorrow remain
12、s unknown.（3）Who will be our monitor hasnt been decided yet.（4）Whom we must study for is a question of great importance.（5）What caused the accident remains unknown.,1）主语从句在句首时，必须由连接词引导，不能省略这些连接词。,误：They should like each other is natural.,2)如果主语从句放在句首，不能用if引导，但是如果用it 做形式主语，而把主语从句放在句末时，也可以用if引导.,误：If
13、Mary really heard him is really doubtful.,注 意,正：That they should like each other is natural.It is natural that they should like each other.,正：Whether Mary really heard him is really doubtful.It was doubtful if Mary really heard him.,What you left are only several old books.What you said is of great
14、importance.,3）主语从句中用陈述语序,后面的谓语动词用第三人称单数,4）“what”引导主语从句时，谓语动词：常与其后的名词作表语一致，且根据句子的语境而定。eg：,5).用于 It is important/natural/necessary/impossible that.句型中,主语从句应使用虚拟语气,用“should+动词原形”的形式,should有时可以省略。6).在 It+be+suggested/advised/ordered/requested/insisted/required 中,that从句的谓语也应该用“should+动词原形”的形式,should有时可以省
15、略。,_ he made an important speech at the meeting was true.A.That B.Why C.What D.How,2._well go camping tomorrow depends on the weather.A If B Whether C That D Where,3._ is known to us all that America is a developed country.A Which B As C What D It,4.Its known to us all _ a form of energy.A.water is
16、B.that water is C.is water D.that water to 5.It worried her a bit _ her hair was turning gray.A.whether B.that C.what D.when6.What I say and think _ none of your business.A.is B.are C.has D have,7._ Tom liked to eat was different from _.A.Thatthat you had expected B.What that you had expectedC.Thatw
17、hat you had expected D.Whatwhat you had expected8(09天津7)It is obvious to the students _ they should get well prepared for their future.as B.which C.whether D.that9.(07陕西8)parents say and do has a life-long effect on their children.A.ThatB.WhichC.WhatD.As,10.(07福建35)It is none of your businessother people think about you.Believe yourself.A.howB.whatC.whichD.When11.(06山东27)team wins on Saturday will go through to the national championships.No matter what B No matter whichC.WhateverD.Whichever,
