主语从句讲解

1、Subject Clauses主语从句主语从句Grammar What part does the underlined part serve as in each sentence? A tree has fallen across the road. You are a student. To find your way can be a problem. Smoking is bad for you. “How do you do?” is a greeting. What she said is not yet known. That we shall be late is certa

2、in. Whether he will go there is not known . How we can help the twins will be discussed at the meeting.定义：定义： 用作主语的从句叫主语从句，它是名词用作主语的从句叫主语从句，它是名词 性从句之一。性从句之一。引导主语从句的连接词有：引导主语从句的连接词有： 从属连词从属连词: that, whether； 连接代词连接代词: who (whoever), whom, whose, what (whatever)和和which (whichever)； 连接副词连接副词: when, whe

3、re, how和和why。1.连接词：连接词：1）从属连词：）从属连词：that， whether 引导主语从句引导主语从句只起引只起引导作用导作用，在主语从句中，在主语从句中不充当任何成分不充当任何成分，that本身本身无实际意义，但不能省略无实际意义，但不能省略. whether意为意为“是否是否”，放在句首句末皆可。放在句首句末皆可。 That price will go up is certain. That he will come is certain. Whether we go by train or by boat makes no difference. Whether h

4、ell come here isnt clear. 2)连接代词连接代词 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.Who killed the scientist remains a question.Whom she borrowed money from still puzzled h

5、im.3)连接副词连接副词when，where， how， why等。等。How this happened is not clear to anyone. 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.Make sentences :Its certain .well be late. Is he coming or not ？We dont knowWhat does

6、he want to tell us?We dont knowWhen will you come back?It doesnt matter.Its certain that we will be late.That well be late is certain.We dont know whether he is coming or not .Whether he is coming is not known.We dont know what he wants to tell us.What he wants to tell us is not known.When you will

7、come back doesnt matter.It doesnt matter when you will come back.主语从句后置主语从句后置! 为了避免主语冗长为了避免主语冗长,句子头重脚轻句子头重脚轻,经常用经常用 it 作作 形式主语形式主语,主语从句放在后面作真正的主语主语从句放在后面作真正的主语. 例例: 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

8、 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 + be + 形容词形容词 + that 从句从句(obvious, true, surprising, good, wonderful, funny, possible, likely, certain, probable, etc.) 如：如：It is certain that she will do well in her exam. B. It + be + 名词

9、词组名词词组 + that 从句从句 (an honour, a fact, a pity, etc）如）如：Its a pity that we cant go. C. It + be + 过去分词过去分词 + that 从句 (said, reported, thought, expected, decided, announced, etc。） 如：It is said that Mr. Green has arrived in Beijing. D. It + 不及物动词或短语不及物动词或短语 + that 从句从句( seem，happen, doesnt matter ,turn

10、out） 。如：。如：It happened that I was out that day. It doesnt matter whether she will come or not. 1）主语从句在句首时，必须由连接词引导，不能省略这些）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。连接词。误：误：They should like each other is natural.2)如果主语从句放在句首，不能用如果主语从句放在句首，不能用if引导，但是如果用引导，但是如果用it 做做形式主语，而把主语从句放在句末时，也可以用形式主语，而把主语从句放在句末时，也可以用if引导引导.误

11、：误：If Mary really heard him is really doubtful.注注 意意正：正： That they should like each other is natural. It is natural that they should like each other.正：正：Whether Mary really heard him is really doubtful. It was doubtful if Mary really heard him.1. What you left are only several old books.2. What you

12、said is of great importance.3）主语从句中用陈述语序）主语从句中用陈述语序,后面的谓语动词用第三人称单数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：引导主语从句时，谓语动词： 常与其后的名词作表语一致常与其后的名词作表语一致 ，且根据句子的语境而定。，且根据句子的语境而定。 eg：5) . 用于用于 It is important / natural / necessary / impossible that.句型中句型中, 主语从句应使用虚拟语气主语从句应使用虚拟语气, 用用“should + 动词原形动词原形”的形式的形式, shoul

13、d有时可以省略。有时可以省略。6) . 在在 It + be + suggested/advised/ordered/requested/ insisted/required 中中, that从句的谓语也应该用从句的谓语也应该用“should + 动词原形动词原形”的形式的形式, should有时可以省略。有时可以省略。1.Where shall we spend the holiday isnt decided.2.You have made a mistake is a fact.3.That is certain that we can win.4.No matter who leave

14、s the room last ought to turn off the lights.5.If the policemen will come is not certain.we shallThat you haveIt isWhoeverwhether改错练习改错练习6.It is say that he was a famous writer.7.It is seemed that it is going to rain soon .8.That is fact that she won the first place.9. Who leaves the room last ought

15、 to turn off the lights.10.It is important that a student learns a foreign language.said seemsIt is a factWhoevershould learn1._ 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 al