名词性从句【知识要点】在句中起名词作用的从句叫名词性从句，它包括主语从句、宾语从句、表语从句和同位语从句。引导名词性从句的连接词连接词词义功能that无词义不作成分，只起连接作用whether/if是否不作成分，起连接作用what,which什么，哪个作主语、宾语、表语who,whom,whose谁，谁的作主语、宾语、定语when,where,how,why什么时候/地方，怎么样，为什么作状语how many/much多少作定语how soon/often/long/much多久，多久一次，多长，多么作状语.词义及功能同疑问词whatever=anything that无论什么作主语、宾语、表语、定语whosever=anyone whose无论谁的作主语、宾语、定语、表语whichever=anything that无论哪个作宾语、定语、主语、表语whoever=anyone who无论谁作主语whomever=anyone whom无论谁作宾语主语从句主语从句是在复合句中充当主语的从句，通常放在主句谓语动词之前或由形式主语it代替，而本身放在句子末尾。引导主语从句的连接词主要有三类：连接词that，whether；连接代词what，who，which, whose，whatever，whichever，whoever, whomever等；连接副词when，where，why，how等。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。如：It is a pity that you didnt go to see the film.你没去看那场电影真是遗憾。It doesnt interest me whether you succeed or not.你成功与否对我没有什么吸引力。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4)it 过去分词从句It is reported that.据报道 It has been proved that.已证实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。如： It is said that President Jiang will visit our school next week.(right)据说江主席下周要来我校视察。 That President Jiang will visit our school next week is said.(wrong)3) It happens.，It occurs. 结构中的主语从句不可提前。如：It occurred to him that he failed in the examination.(right)他考试没及格。That he failed in the examination occurred to him.(wrong)4)It doesnt matter how/whether .结构中的主语从句不可提前。如：It doesnt matter whether he is wrong or not.(right)他是不是错了，这一点不重要。Whether he is wrong or not doesnt matter.(wrong)5)含主语从句的复合句是疑问句时，主语从句不可提前。如： Is it likely that it will rain in the evening? (right) Is that will rain in the evening likely? (wrong) 傍晚有可能下雨吗？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。如： What you said yesterday is right. 你昨天说的是对的。一、 宾语从句宾语从句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。引导宾语从句的连接词主要有三类：连接词that，whether，if等，连接代词which,what，who，whom, whose，whatever，whichever，whoever, whomever,等，连接副词when，where，why，how等。1.作动词的宾语1)由that引导的宾语从句（that 通常可以省略）,如：I heard that he joined the army. 我听说他参军了。2)由what，whether (if)引导的宾语从句，如：She did not know what had happened. 她不知道发生了什么事。3)动词间接宾语宾语从句。如：She told me that she would accept my invitation. 她跟我说她愿意接受我的邀请。2.作介词的宾语，如：Our success depends upon how well we can cooperate with one another.我们的成功取决于我们的合作情况。3.作形容词的宾语，如： I am afraid (that)Ive made a mistake. 我恐怕是犯错了。 【特别提示】 that 引导的从句常跟在下列形容词后作宾语： anxious，aware，certain，confident，convinced，determined，glad，proud，surprised，worried，sorry，thankful， ashamed，disappointed，annoyed，pleased，hurt，satisfied，content 等。也可以将此类词后的that 从句看作 原因状语从句。4.it 可以作为形式宾语it不仅可以作为形式主语，还可以作为形式宾语而把真正的宾语that 从句放在句尾，特别是在带复合宾语的句子中。如：We heard it that she would get married next month. 我们听说她打算下个月结婚。【特别提示1】1宾语从句的语序在宾语从句中要用陈述句语序。如：He asked me when we could set out the next day他问我第二天什么时候可以出发。2宾语从句的时态(1)当主句的谓语动词是一般现在时时，其宾语从句的时态可以是任何适当的时态。如：she says(that)she will leave a message on his desk她说她要在他桌子上留个便条。(从句是一般将来时)She says(that)she has never been to Mount Emei她说她从来没有去过峨眉山。(从句是现在完成时)(2)当主句的谓语动词是一般过去式时，其宾语从句的时态一般要用适当的过去时态。如：He said there were no classes yesterday afternoon他说昨天下午没有课。(从句是一般过去时)He said that he was going to take care of the baby他说他会去照看这个婴儿。(从句是过去将来时) (3)当宾语从句是表达客观真理和规律的句子时，其时态仍旧用一般现在时。如：The teacher told us that nothing is difficult if we put our hearts into it老师告诉我们世上无难事，只怕有心人。He said that light travels much faster than sound他说光比声音传播得快。【特别提示2】在使用宾语从句时需要注意下面几点：(1)动词find，feel，think，consider，make，believe，guess，suppose，assume等后有宾语补足语时，则需要用it作形式宾语，而将that宾语从句后置。如：I think it necessary that we take plenty of boiled water every day我认为每天多喝开水是有必要的。(2)hate，like，take，owe，have，take for granted等表示“喜欢；痛恨；认为”的动词或动词短语和see to表示“注意，留意”后有宾语补足语时，需要用it作形式宾语而将宾语从句后置。如：I hate it when they talk with their mouth full of food我讨厌他们满嘴食物说话。When you start the engine，you must see to it that the car is in neutral启动发动机时，一定要使汽车的离合器处于空档位置。(3)介词后的宾语从句。如：She is always thinking of how she can do more for others她总想着如何才能为别人做得更多。二、 表语从句表语从句是在复合句中作表语的名词性从句，放在系动词之后，一般结构是“主语连系动词表语从句”。可以接表语从句的连系动词有be，look，remain，seem等。常由连接词that，whether；because, as if/though连接代词who，whom，whose，which，what，whoever，whomever，whichever，whatever；连接副词when，where，how，why引导。另外，常用的还有The reason is that. 和It is because 等结构。如：【特别提示】(1) as/as if/as though引导的表语从句常跟在特定动词后面，如seem，appear，look，taste，sound，feel等。如：It sounds as if someone is knocking at the door听上去好像有人在敲门。 (2) 当主句的主语是reason时，表语从句一般由th