名词性从句的引导词引导词是否在名词性从句中充当成分的情况连接代词：what, which, who, whom, whose连接副词：when, where, why, howwhat, which 在从句中作主语、宾语、表语或定语；who 在从句中作主语、表语；whom 在从句中作宾语；whose 在从句中作定语；when, where, why, how 在从句中分别作时间状语、地点状语、原因状语、方式状语连词that 否连词whether, if 否名词性从句的引导词在高考中的基本用法详见下面的总结：1.引导特殊疑问句的疑问词在转为引导名词性从句时, 即成为连接代词（主要包括what, which, who, whom, whose）或者连接副词（主要包括when, where, why, how）.注意体会如下例句：Choose which you like best. 选你最喜欢的.// Who has taken away my bag is unknown. 谁拿走了我的包还不知道.// Have you decided whom you are to nominate as your candidate? 你们是否已经决定提名谁做候选人了?// He asked when Mr. Gilbert would be allowed to gohome. 他问什么时候可以允许吉尔伯特先生回家.// Where we can look up his address is still a problem. 我们在哪儿可以查到他的地址还是个难题.// Why he did that wasn't quite clear. 他为什么做那件事还不十分清楚.// How they will solve the serious problem has not been decided. 他们将怎样解决这个严重问题还没有决定.以下两种特殊情况要给予特别关注：(1) what 作连接代词引导的名词性从句既可以表示一个问“什么……?”的问题, 也可以表示相当于“名词/代词＋关系代词引导的定语从句”结构的意思, 这种特殊用法在语法上被称作“关系代词型的what”, 注意体会如下例句：He is not what (=the person that) he was a few years ago. 他不是几年前的他了.// This is what (=the place that) they call Salt Lake City. 这就是他们称作盐湖城的地方.// What (=the place that) is now the North Sahara Desert was once a civilized world. 现在的北部撒哈拉沙漠曾是一个文明世界.// Our income is now double what (=the income that) it was ten years ago. 我们现在的收入是十年前的两倍.// The color of the flower is different from what (=the color that) it was in the morning. 花朵(现在的)颜色与它早上的颜色不同.(2) 带'ever 后缀的疑问词除引导让步状语从句之外, 还可以引导名词性从句(“no matter＋疑问词”的结构只能引导让步状语从句, 不可以引导名词性从句), 注意体会以下例句：Whoever wants to see this film can go with us tonight.无论谁想看这部电影, 今晚都可以和我们一起去.// You can give the ticket to whomever you like. 你可以把票给任何你想给的人.// All the books are here. You may borrow whichever （book） you like. 所有的书都在这儿, 你愿借哪本就借哪本.// I'll do whatever you ask me to do. 你叫我做什么, 我就做什么.2.that 引导名词性从句时后面接完整的陈述句, that 只起引导名词性从句的作用而不充当该名词性从句中的具体成分；引导宾语从句时that 常可省略, 但引导主语从句、表语从句、同位语从句时that 通常不被省略.例如：She hoped （that） he would arrive on time. 她希望他按时到达.（宾语从句）That she was chosen made us very happy. 她被选中了让我们很开心.（主语从句）I have the belief that I will succeed. 我怀有必胜的信念.（同位语从句）that, what 引导名词性从句的区别在于：that 在其引导的名词性从句中不充当任何成分, 在有的情况下可以省略；what 需要在其引导的名词性从句中充当主语、宾语、表语或者定语, 而且引导名词性从句的what在任何情况下都不能省略.例如：That he will succeed is obvious. 显然, 他会成功.（引导主语从句的that 不在其中充当具体的句子成分）What she told me is not true. 她所告诉我的都不是真的.（what 在其引导的主语从句中作宾语）3.whether 与if 均可以引导表示“是否”之意的名词性从句, 且whether 与if 均不在这种名词性从句中充当具体的句子成分.在引导宾语从句时whether 与if 一般可以互换, 但在引导主语从句、表语从句、同位语从句、介词后的宾语从句、放于句首的宾语从句或者名词性从句中包含or （not）时通常只能用whether 作引导词.注意体会下列例句：I don' t know if/whether I can help you. 我不知道我能否帮助你.（宾语从句）// Whether we can really help you, I don't know yet. 我们是否真的能帮助你, 我还不知道.（位于句首的宾语从句）// The teacher worried about whether he had hurt the girl's feelings. 老师为是否伤害了那女孩的感情而担心.（介词后的宾语从句）// The question is whether they can cooperate with us. 问题是他们能否与我们合作.（表语从句）// The question whether he should come himself or send a substitute must be decided upon. 他该亲自来还是派人替他来, 这个问题必须定下来.（同位语从句）// The little girl asked her father whether she should go to the party or not. 那女孩问她的父亲她应不应该参加这个晚会.（包含or not 的宾语从句）注意：肯定形式的doubt 后面通常接whether/if 引导的宾语从句, 否定形式的doubt后面通常接that 引导的宾语从句, 例如：I doubt whether it's true. 我怀疑它是否是真实的.// I doubt if that was what he wanted. 我怀疑那是否是他所想要的.// I don't doubt that you are honest. 我不怀疑你的诚实.// She never doubted for a moment that she was right. 她对自己是正确的这一点从不怀疑.［考题1］—Could you do me a favor?—It depends on ___ it is. （2006 北京）A. whichB. whicheverC. whatD. whatever［答案］C［解析］下划线处的引导词引导on 后的宾语从句, 并且在该宾语从句中充当表语, 表示疑问句“What is it? （你要我帮的忙是什么?）”的含义.注意：题干中没有用“whatever” 进行强调的必要.［考题2］—I think it's going to be a big problem.—Yes, it could be.—I wonder __ we can do about it. （2002 北京春）A. ifB. howC. whatD. that［答案］C［解析］下划线处的引导词引导wonder 后的宾语从句并且在该宾语从句中充当do 的宾语, if, that 引导名词性从句时都不充当名词性从句中的句子成分, how 引导名词性从句时充当名词性从句中的方式状语, 因此应排除A、B、 D 而选出 C.本题中what we can do about it 可以理解为对应于疑问句“What can we do about it?”的名词性从句, what 引导的这种名词性从句跟其他疑问词形式的引导词所引导的名词性从句的含义相近.［考题 3 ］You can only be sure of _ you have at present: you cannot be sure of something ____ you might get in the future. (2007 安徽)A. that; whatB. what; 不填C. which; thatD. 不填; that［答案］ B［解析］第一个下划线处应填入一个可以引导of 的宾语从句泛指“你现在所拥有的东西”且在该宾语从句内部充当have 的宾语的词, 这样的引导词只能是what, 由此可以直接排除选项A、C、 D 而选出 B.［考题4］__ we can 't get seems better than ___ we have. (1996)A. What; whatB. What; thatC. That; thatD. That; what ［答案］ A［解析］名词性从句what we can 't get 和what we have 中what 都充当宾语, 都属于关系代词型的what, 本身不表示疑问而表示泛指相关的事物；“what we can't get”相当于包含定语从句的“things that we can't get”, “what we have” 相当于包含定语从句的“things that we have”.［考题 5 ］It is generally considered unwise to give a child he or she wants. （1997）A. howeverB. whateverC. whicheverD. whenever［答案］B［解析］whatever 在这里的用法跟关系代词型的what 一样, 其引导的名词性从句“whatever he or she wants”泛指一个孩子想要的任何东西.［考题 6 ］It was a matter of _ would take the position. （1998 上海）A. whoB. whoeverC. whomD. whomever［答案］A［解析］下划线处的引导词所引导的名词性从句充当介词of的宾语, 在其引导的宾语从句内部充当的是主语（通常用who 指代）而不是宾语（通常用whom 指代）, 而且题干中没有提供强调“任何人”的语境, 因此应填入引导词who.［考题7］Could I speak to __ is in charge of International Sales, please? （2007 山东）A. anyoneB. someoneC. whoeverD. no matter who［答案］C［解析］下划线处引导speak to 之后的宾语从句, 表示（负责国际销售的）任何人”, 四个选项中只有whoever 适合.［考题8］Mary wrote an article on ___ the team had failed to win the game. (2005)A. whyB. whatC. whoD. that［答案］A［解析］下划线处引导的名词性从句属于介词on 的宾语, 在该名词性从句中引导词充当原因状语, 所以应选 A.［考题9］Please remind me __ he said he was going. I may be in time to see him off. (2006)A. whereB. whenC. howD. what［答案］B［解析］题干中所有句子都围绕时间展开, 因此应填入表示时间的when 引导remind 的直接宾语.［考题10］Information has been put forward __ more middle school graduates will be admitted into universities. (上海2000)A. whileB. thatC. whenD. as［答案］B［解析］陈述客观情况的名词性从句的引导词之后是完整的陈述句, 引导词本身不充当该名词性从句中具体的句子成分, 有这样用法的引导词只能是that.本题下划线处引导了information 的同位语从句(为避免头重脚轻, 本句中information 的同位语从句与information 之间被谓语动词部分隔开）.［考题11］The other day, my brother drove his car down the street at ___ I thought was a dangerous speed. （2004 上海春）A. asB. whichC. whatD. that［答案］C［解析］下划线处的引导词引导介词at 的宾语从句, 该引导词在at的宾语从句中所包含的又一个宾语从句（充当think 的宾语）里充当主语, 特指说话人的兄弟驾车的速度, 四个选项中只有关系代词型的引导词what具有这样的用法. 注意：本题中at 的宾语从句中又包含一个宾语从句, 总共出现了两个宾语从句, 其中第二个宾语从句（I thought 之后的宾语从句）的引导词that 被省略了.［考题12］Elephants have their own way to tell the shape of an object and ____ it is rough or smooth. （2005 天津）A. 不填B. whetherC. howD. what［答案］B［解析］题干中的or 意味着下划线处需要表示“是否” 的含义.［考题13］__ team wins on Saturday will go through to the national championships. （2006 山东）A. No matter whatB. No matter whichC. WhateverD. Whichever［答案］D［解析］下划线处引导全句的主语, 因此不能选用只能引导让步状语从句的选项A、B；下划线处表示“任何一支（获胜的球队）”之意, 用which 的相关形式更为合适, 因此进一步排除 C 而选出 D.。