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1、主语从句一、概念：在复合句中起主语作用的从句叫主语从句。(一） 连接词 从属连词：that、whether；关系代词：who, what, which， whom, whose， whatever， whoever, whomever， whichever；关系副词:when, where， how, why， however， whenever, wherever等；例: What he saidis true. That you dont like himis noneof my business。Whether the football gamewillbe playeddepends
2、on theweather.主语从句的时态:不受主句的时态影响和限制。(1）_ he finished writing the composition in such a short time _（惊讶） us all。（2）_we will go for an outing tomorrow _（remains，remained） unknown。（3）_ will be our monitor _（be） decided yet。（4)_we must study for _ （be) a question of great importance。（5)_ caused the accid
3、ent _（remains，remained）unknown。（6）_ you did _ (be)right.（7)_ watch _（be） lost is unknown.(8）_we need _(be) time。（9）_ we need _(be) good doctors。小结:（1)主语从句的时态:不受主句的时态影响和限制.（2)连词位于句首不能省略（3）主语从句大多数情况下视为三单,但也有例外,如例91. 从属连词that，whether引导的主语从句.从属连词that,whether在主语从句中的作用只是引导主语从句,在从句中不担任成分,不能省略。例： _ they wil
4、l gois certain。_ she will come or notis still a question。 _ shes coming or notdoesnt matter too much。2. it作形式主语引导主语从句。如果主语从句太长，为避免句子结构头重脚轻，我们可用it作形式主语，而把主语从句放在主句谓语部分之后.That引导的主语从句可用it代替,that 不可省略。用作it作形式主语的结构：（1）It is/was +形容词+that 从句Its natural that很自然 Its obvious that 显而易见Its fortunate that 幸运的是 I
5、ts （im)possible（不）可能Its unlikely that不可能 Its strange that奇怪的是（2）It is/was +名词+that 从句Its a pity that遗憾的是 Its a fact that 事实是Its good news that是好消息 Its a wonder that不足为奇Its an honour that 非常荣幸 Its a shame that真是可耻Its common knowledge that 是常识（3）It +不及物动词+that 从句It seems that 似乎 It happened that碰巧It a
6、ppears that看来 It turns out that结果(4）It is/was +过去分词+that 从句Its not known that 不得而知 Its said that据说Its reported that 据报道 Its decided that尚未决定Its believed that 据认为 Its announced that据宣布It suddenly struck me (occur to me that 我突然想到(感觉到）(5)其他It doesnt matter 是无关紧要的It makes no difference 毫无区别It is of lit
7、tle consequence that无关紧要It is a pity_ she has made such a mistake。 她犯这样的错误是令人遗憾的事。Its strange_ he didnt come yesterday. 他昨天没来是很奇怪的。It is reported_ the number of wild animals in Africa is decreasing.据报导非洲野生动物的数量正在减少。It is said_ there was a terrible plane crash this morning。据说今天早上有一起可怕的飞机坠毁事故。1）主语从句在句
8、首时,必须由连注意:接词引导，不能省略这些连接词；但是如果用it做形式主语，而把主语从句放在句末时，从属连词that可以省略。误:They should like each other is natural.正：That they should like each other is natural。正：It is natural that they should like each other。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 Mary really heard him is really doubtful
9、。正:It was doubtful if Mary really heard him。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有时可以省略。5） 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有时可以省略.Does _ matter if he c
10、ant finish the job on time ？A。 this B. that C。 he D. it _ is a fact that English is being accepted as an international language.A. There B。 This C。 That D。 ItIt is necessary that a college student _ at least a foreign language.A。 masters B. should master C。 mastered D。 will master _ is known to ever
11、ybody, the moon travels round the earth once every month.A。 It B. As C. That D。 What 3、由关系代词引导的主语从句。(1）关系代词who， what， which, whom， whose， whatever， whoever， whomever, whichever等,引导主语从句时，它们分别在从句中担任主语、宾语或定语,不能省略._ leaves the room lastought toturn off the lights. 走得最晚的应当关灯._ you have donemightdo harm t
12、ootherpeople。 你的行为可能伤害别人。_ he said at the meetingastonished everybody present.他在会议上的发言时所有入会者吃惊。_ made the long distance callis not important。 谁打的长途电话并不重要.（2）what引导主语从句“的东西/事情”时，可用来表示the thing（s)which这种意思，引导从句，表示一样东西与一件事情，这种用法的what称为关系代词型what，who,whom，which，what可以和ever构成合成词，和what一样引导从句，ever起强调作用.这些关系
13、词在句子中充当成分，所以不能省略。此类主语从句不能用形式主语it引导._（=The thing which I need）is a mobile phone.我所需要的是一部移动电话。_ leaves the office （=Any one who leaves the office）shouldtell me.无论是谁离开办公室都应该告诉我。4、关系副词引导的主语从句.连接副词有when, where, why， how， however， whenever, wherever等引导主语从句时，它们在从句中担任状语，不能省略.此类主语从句可以转换为以it作形式主语的句子。_ he didnt come hereis not clear to anyone. 他为什么没来谁也不清楚。_ a telephone worksis a question which not everyone can answer. 电话是怎样工作的，这个问题并不是每个人都能回答。_ she has goneis not known yet。 她去了哪儿,还不知道。_ they will starthas not been decided yet。 他们何时动身还未定下来._ he did itdidnt concern me. 他为什么做这件事与我无关。5、主语从句不可位于句首的四种情况。(
