名词性从句在句子中起名词作用的句子叫名词性从句(Noun Clauses）。

名词性从句的功能相当于名词词组, 它在复合句中能担任主语、宾语、表语、同位语、介词宾语等，因此根据它在句中不同的语法功能，名词从句又可分别称为主语从句、宾语从句、表语从句和同位语从句。

高中英语定语从句和名词性从句综合训练名词从句名词从句有四类：宾语从句、主语从句、表语从句、同位语从句。

例如：宾语从句：I don’t know where he will go.主语从句：Where he will go is unknown.表语从句：The problem is how we can get so much money.同位语从句：We all feel sorry about the news that he failed in the game.下面几点是学习名词从句要加以注意的：1．w hether和if都可以引导宾语从句表达“是否”意，（即引导宾语从句时if和whether可以互换）但以下几种名词从句要用whether（不用if）引导：（1）引导主语从句，且在句首时。

例：Whether he has won the tennis is not known.(但It is not known whether/if he has won the tennis).（2）引导表语从句时。

例The problem is whether he can get a job.（3）引导同位语从句时。

例：I have no idea whether he will come.（4）介词后的whether从句。

例：I worry about whether I hurt her feelings.2．位于句首引导主语从句的that不可忘。

例如：That he got the first place in the competition surprised all of us.3．在“It is suggested/proposed/ordered/a pity/no wonder/necessary/strange/…＋that从句”结构中，that从句谓语有时用（should）do这样的虚拟语气形式。

例如：It is suggested that we(should) improve the relations between us.It is a pity that one(should) stay in one place all one s life.It is strange that she should have failed to see her own shortcomings（缺点）.4．在“The reason why…is that…”句式中that不要误为because.例如：The reason why he didn t go to school yesterday is that he was ill.5．名词从句中that,what用法比较：引导名词从句的that是连词，在句中无成份，无意义，而what是连接代词，what＝the thing(s) that.例如：It was told in yesterday s newspaper that what the students had done was praised by the factory.I know that he will study.I know what he will study.That he works hard at his lessons is known to us all.What he works hard at is known to us all.All I ask is that you should tell the truth./He is not what(＝the person that)heused to be. 他和以前大不相同了。

6．w here在名词从句中的使用特点：where在名词从句中有时可以变为“the place where”,有时可以变为“介词＋the place where” 形式。

例如：主从：Where(＝The place where)she has gone is still unknown.宾从：Would you please tell me where(＝the place where) Mr Smith lives?表从：Your dictionary remains where(＝in/at the place where)you put.同位从：Have you any idea where(＝of the place where) she is spending her holidays?7．无论是哪种名词从句都是陈述语序。

例如：I know where he lives./Please tell me what her name is.当一个特殊疑问句本身就是陈述语序（即“主＋谓＋（宾）”或“主＋系＋表”结构），将其变为间接引语（即宾语从句）时，无需改变语序。

例如：What s the matter with him? She asked me what was the matter with him.Who looks after your grandfather? He asked me who looked after my grandfather.第一节知识点讲解顾名思义，主语从句在句子中作主语。

有时本身出现在主语的位置上，也有时出于句子结构的考虑退到句子的尾部，前面用形式主语it代替。

从句作主语时，谓语动词一般为单数形式。

如:What I saw was beyond any verbal description.That his hair was turning grey worried him a bit.Why the company denied the contract is still unknown.When and where the government will build a city square is under discussion.It is pretty annoying that a small part of the machine is missing.It remains to be seen whether the new novel will be well received.Tips: 主语从句的that绝对不能省去。

因为句子是不能做主语的，故用that引导。

若去掉则没有了主语，而宾语从句的that可省。

主语从句：That he is right is known to all of us.宾语从句：We all know (that) he is right.1. It 作形式主语和it引导强调句的比较It 作形式主语代替主语从句，主要是为了平衡句子结构，主语从句的连接词没有变化。

而it引导的强调句则是对句子某一部分进行强调，无论强调的是什么成分，都可用连词that。

被强调部分指人时也可用who/whom。

例如：a) It is a pity that you didn’t go to see the film. 你不去看那场电影真可惜。

b) It doesn’t interest me whether you succeed or not. 我对你成功与否不感兴趣。

c) It is in the morning that the murder took place. 谋杀案是在早上发生的。

（强调句型）d) It is John that broke the window. 是John打碎的窗户。

（强调句型）2. 用it 作形式主语的结构(1) It is ＋名词＋从句It is a fact that … 事实是…It is an honor that …非常荣幸It is common knowledge that …是常识(2) It is ＋形容词＋从句It is natural that… 很自然…It is strange that… 奇怪的是…(3) It is ＋不及物动词＋从句It seems that… 似乎…It happened that… 碰巧…It appears that… 似乎…(4) It ＋过去分词＋从句It is reported that… 据报道…It has been proved that… 已证实…It is said that… 据说…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 /reported…结构中的主语从句不可提前。

例如：正确表达：It is said that President Jiang will visit our school next week.错误表达：That President Jiang will visit our school next week is said.（3）It happens/occurs…结构中的主语从句不可提前。

例如：正确表达：It occurred to him that he failed in the examination.错误表达：That he failed in the examination occurred to him.（4）It doesn’t matter how/whether …结构中的主语从句不可提前。

例如：正确表达：It doesn’t matter whether he is wrong or not.错误表达：Whether he is wrong or not doesn’t matter.（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：正确表达：Is it likely that it will rain in the evening?错误表达：Is that will rain in the evening likely?4. what 与that 在引导主语从句时的区别what 引导主语从句时在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：a) What you said yesterday is right.b) That she is still alive is a consolation宾语从句就是在复合句中作宾语的名词性从句，通常放在主句谓语动词(及物动词) 或介词之后。