名词从句专项复习名词从句名词从句：在复合句中充当主语、宾语、表语、同位语、介词宾语的句子其功能相当于名词，根据它在句中不同的语法功能，可分为主语从句、宾语从句、表语从句和同位语从句结论：引导名词性从句的连接词可以分为三类1、本身无意义在所引导的名词性从句中也不作成分：that2、本身有意义，但在所引导的名词性从句中不作成分：whether/if, as if/though，because3、本身有意义，在所引导的名词性从句中也作成分：which，what，who，whom，whoever, whichever，whatever，when，why，where，how等引导名词性从句的关联词连接代词who, whom, whose, which, what, whatever（本身有意思；在从句中作成分）连接副词how, why, when, where however, wherever（本身有意思；在从句中作成分）连接词that,（本身没有意思；在从句中不作成分）whether, if, because，as if /as though（本身有意思；在从句中不作成分）四种名词性从句的简要介绍一、主语从句：在句中作主语的句子 主语从句通常由从属连词that，whether 和连接代词what, who, which, whatever, whoever以及连接副词how,when,where, why等词引导。
▲that在从句中无词义，只起连接作用；连接代词和连接副词在句中既保留自己的疑问含义、又起连接作用，在从句中充当成分如：What he wants to tell us is not clear. 他要跟我们说什么，还不清楚Who will win the match is still unknown.Where the English evening will be held has not yet been announced. That he stole a bike was true. ▲单个的主语从句作主语时，谓语动词用单数形式如果是两个或两个以上的主语从句作主语，谓语动词则用复数形式如： Where and when he was born has not been found. When the person was murdered and why he was murdered are still unknown. ▲有时为避免句子头重脚轻，常用it 代替主语从句作形式主语放于句首，而把主语从句置于句末主句的谓语动词一般用单数形式常用句型如下：（1）It + be + 名词 + that从句It is a fact that…It is an honor that…It is a pity that…（2）It + be + 形容词 + that从句It is natural that…It is necessary that…It is important that…It is obvious that…（3）It + be + 动词的过去分词 + that从句It is reported that…It is believed that…It is known to all that…It has been proved that…（4）It + 不及物动词 + that 从句It seems that…It occurred to me that…It happened that…二、宾语从句：名词句用作宾语的从句引导宾语从句的关联词与引导主语从句、表语从句的关联词大致一样，在句中可以作谓语动词或介词及非谓语动词的宾语。
1）由连接词that引导的宾语从句：that在句中不担任任何成分，在口语或非正式的文体中常被省去，但如从句是并列句时,第二个分句前的that不可省如：He has told me that he will go to Shanghai tomorrow. We must never think we are good in everything and that others are good in nothing. （2）在demand, order, suggest, advise, decide, insist, desire, request, command等表示要求、命令、建议、决定等意义的动词后，宾语从句常用“should+ 动词原形”如：I insist that she (should) do her work alone. The commander ordered that troops (should) set off at once.但是, 如果suggest作“表明、暗示”讲, insist作“坚持说、坚持认为”讲，则其后的宾语从句中应该用陈述语气如：The smile on his face suggested that he had passed the examination.（3）用whether或if引导的宾语句whether和if均可引导动词后的宾语从句，常可互换。
但从句中有or not时或介词后的宾语从句中只能用whether连接其它名词性从句，如：主语从句、表语从句、同位语从句只用whether如：I don’t care about whether you have money or not.Everything depends on whether we have enough money. （4）宾语从句中的时态呼应 ①宾语从句的谓语动词时态受主句谓语动词的影响，如果主句的谓语动词是一般现在时从句中的谓语动词可以用各种时态如：I know that he studies English every day. I know that he studied English last term. I know (that) he will study English next year. We all know that he has studied English since 1998. ②如果主句中的谓语动词用了一般过去时，则从句中的语动只能用过去时的某种形式，如一般过去时，过去进行时，过去将来时等如：We believed that he had earned enough money to build a house. The teacher told us that Tom had left us for America． ③当从句表示的是客观真理，科学原理，自然现象，则从句仍用现在时态。
如：The teacher told us that the sun rises in the east.（5）当主句是I/ We think (suppose, expect, believe, guess, imagine) 时，其后的宾语从句如果是否定形式，常把否定词not从从句中转移到主句中成为否定的转移如：We don’t believe that he will win the game. I don’t think he will do so. ▲注意：doubt 用于肯定结构时，后面用whether/ if 引导名词性从句；用于否定结构或疑问结构时，后面用that 引导名词性从句be sure用于肯定句或疑问句时，后接 that 引导的名词性从句；用于否定句时，后接whether/if 引导的名词性从句 三、表语从句：在句中作表语的句子引导表语从句的关联词与引导主语从句的关联词大致一样，表语从句位于系动词后，有时用as if, because 引导其基本结构为：主语 + 系动词 + that从句如：The fact is that we have lost the game. That’s just what I wantThis is where our problem lies. That is why he didn’t come to the meeting. It looks as if it is going to rain. This is because he missed the train by one minute.需要注意的是，当主语是reason 时，表语从句要用that引导而不是because。
如：The reason why he was late was that he missed the train by one minute this morning. 四、同位语从句：说明其前面的名词的具体内容（1）同位语从句一般跟在某些表示抽象概念 的名词后,如 news, idea, information, fact, hope, thought, belief 等，用来说明名词所表示的具体内容（2）引导同位语从句的连接词通常有that, whether和连接副词when, where, why, how；连接代词who，what，whose，which通常不引导同位语从句I have no idea when she will be back. ▲同位语从句与定语从句的区别 1、从词类上区别：同位语从句前面的名词主要是idea，fact，news，hope，belief，suggestion，proposal，word，thought，doubt，truth，possibility，promise，order等名词而定语从句的先行词可以是任何名词，甚至部分代词，主句的一部分或是整个主句，定语从句的先行词逻辑关系上在从句中充当一定成分，同位语从句的名词在从句中不充当任何成分。
2、从性质上区别：定语从句是从句对其先行词的修饰或限制，属于形容词性从句的范畴；而同位语从句表达前面抽象名词的具体内容，属于名词性从句的范畴，从句与前面的名词是对等关系3、从引导词及其在句子中的成分上区别(1)有些引导词如how, whether, what可以引导同位语从句，但不能引导定语从句(2)引导词that引导定语从句时，在从句中一般作主语，表语或宾语[指物时还可以用which代替；指人时还可以用who(m)代替]，并且作宾语时常常省略that在同位语从句中仅起连接作用，不充当任何成分，并且不能省略，也不能用其他词语代替▲区别名词性从句中的whether和if ①_ Whether___ the meeting will be held in the meeting room or in the open is not known to us. ②The problem is ___whether__the students can understand the teacher speaking English all through the class. ③Their doubt __whether__China's economy will keep advancing at high speed is worth considering. ④__Whether_ my lecture will be well received, I don't know.⑤The decision depends on __wh。