语法解-名词从句100521-revised.doc

名词性从句要点讲解20100520名词性从句相当于名词，可分别作主句的主语、表语、宾语和同位语。因此，名词性从句可分为主语从句、表语从句、宾语从句和同位从句。一、 主语从句：从句在句中作主语。Whoever did it should be punished.1) that和what的区别：当句中的主语、表语或宾语都不缺时，应用that，否则用whatWhat is needed has been ready.That she was late made the teacher angry. (that 不可省略)2) 主语从句后的谓语动词一般用单数。3) 有时为避免头重脚轻，常用形式主语结构。a. It is + adj. + thatb. It is + adj. (important/necessary/natural/strange) + that +(should) + 动词原形c. It is + a/an + n. (a fact/ a pity/ an honor/ no wonder) + thatd. It + v. (matters/counts/seems/appears/happens/occurs/turns out/proves ) + thate. It is + done (said/reported/considered) + that二、 表语从句：从句在句中作表语。(一般放在连系动词be, look, seem, sound, remain等之后，有时也用as if引导)My question remains whether he will come. Its where you left it.三、 宾语从句：从句在句中作宾语。(a. 作及物动词或介词的宾语； b. 某些表语形容词或过去分词的宾语)The teacher was satisfied with what Li Ping did. Im afraid that I have made a serious mistake.1) 作及物动词的宾语从句中的that可省略Do you know (that) he has joined the army?that 通常不可省略的情况:a. 句中有两个或多个并列的宾语从句时，第二个及以后的that不可省略：He said he would come to the party and that he would bring his wife with him.b. 由it作形式宾语时，that宾语从句中that也不可省略。He has made it clear that he will not give in.c. that 从句与谓语动词被隔开时：They told us once again that this would never happen.2) it 作形式宾语，常用在下列动词中：think, feel, make, consider, etc.I think it necessary that he should do the test. 3) 注意think, expect, suppose, believe, guess等词的否定前移I dont think the answer is right, is it?四、 同位语从句 (一般置于抽象名词之后，用来补充前一名词的具体内容。常见名词：suggestion, idea, thought, news, order, reason, fact, promise, doubt, problem, question, truth, hope, possibility) We have no idea when she was born.同位语从句与that引导的定语从句的区别We heard the news that our team had won. (同位语从句，不缺任何成分；that没有意义，只起连接作用)The news that you told me yesterday was really exciting. (定语从句，缺少宾语；that在从句中作宾语，在意义上指代先行词news)五、 引导名词性从句的连词1）连接代词：who, whose, whom, what, which。有词义，在从句中担任成分，如主语、表语、宾语、或定语等。2）连接副词：when, where, why, how。有词义，在从句中担任成分，作状语。3）从属连词：that, whether, if, as if/though。在从句中不担任成分，有时可省略。 以that引导的从句（that本身无任何含义，作及物动词宾语that可省略）； 以whether/if引导的从句；只用whether：表从、同位从、句首主从；discuss和介词后；不定式、or not后面跟宾语从句是否定句时，只用if，不用whether。e.g. I wonder if it doesnt rain. 以特殊疑问词(who/what/where/when/why/how)引导的从句；I cant imagine how he did it. We dont know what we should do next. 以what/where/when/whoever/whichever/whatever/whomever等连词引导的名词性从句。what=the thing(s) that; where=the place where; when= the time when; whoever= anyone who; whichever= any one that; whatever=anything that; whomever= anyone whomIt is generally considered unwise to give a child whatever he or she wants.Sarah hopes to become a friend of whoever shares her interests.You can have either of the watches. Take whichever you like.a. 有时what 可用作前置定语，如You cant imagine what funny stories she has told us.b. whoever, whatever 也可引导让步状语从句，相当于no matter who, no matter whatWhatever I said, he wouldnt listen to me. =No matter what I said, he wouldnt listen to me. as if/as though, because引导的（表语）从句。It looked as if it was going to rain.Thats because he didnt work hard enough. (主语不能是reason 或cause)六、 名词性从句的一致问题1) 时态一致：（但从句中是客观真理时，仍用一般现在时态）I was told when I was young that the moon moves round the earth.2) 主谓一致：When and why he came here is not known yet. (主语从句后一般用单数)What he said and what he did were different. (根据意义一致来决定)3) 语气一致：在表示建议(advise/suggest/propose/recommend)、命令(order/direct)、要求(request/demand /desire/urge)、坚持做(insist)等意义的名词性从句里，谓语动词一般用(should) doThe doctors insisted that he was seriously ill and that he (should) be operated on immediately.七、 名词性从句的语序问题1