宾语从句和表语从句详解名词性从句指的是在整个句子中起名词作用的从句。
这种从句可以做主语、宾语、表语、同位语等，所以这类从句包括主语从句、宾语从句、表语从句和同位语从句。
各种名词性从句的结构都是相同的，即由if，whether，that和各种疑问词充当连接词，后接陈述语序。
例如：What they are doing seems very important．（主语从句）他们在做的事似乎很重要。
My hope is that he will be the best student in the class．（表语从句）我的愿望是他能够成为班上最好的学生。
Nobody knows who he is．（宾语从句）大家都不知道他是谁。
I don't like the idea that money is everything．（同位语从句）我不喜欢金钱就是一切这一观点。
引导名词性从句的连接词中，除了that，if和whether之外其它的都作从句中的一个成分。
【宾语从句】在句子中作动词或介词宾语的从句叫做宾语从句。
引导宾语从句的词有连词that，whether，if；连接代词who，which，what以及其强调形式whoever，whichever，whatever；连接副词when，where，why，how等。
例如：Do you know where the Greens live?I have no interest in how rich he is．宾语从句主要用于下面五种结构：1．由that引导的宾语从句（that 引导宾语从句时，特别是在口语中可省略）The boy believes that he will travel through space to other planets．that引导的宾语从句多用于say，think，insist，wish，hope，demand，imagine，wonder，know，suppose，see，believe，agree，admit，deny，expect，explain，order，command，feel，dream，suggest，hear，mean，notice，prefer，request，require，propose，declare，report等后。
当主句谓语动词是think，believe，suppose，expect 等词，而宾语从句的意思是否定时，常把否定转移至主句表示。
例如：I don’t think it is right for him to treat you like that．（＝I think it is not right for him …．）that不能省略的情况：（1）当句中的动词后接多于两个由that引导的宾语从句时，第一个that可省，但后面的that不可省。
如：He said （that）you were too young to understand the matter and that he was asked not to tell you．（2）当主句的谓语动词与that宾语从句之间有插入语时，that一般不可省。
如：Just then I noticed，for the first time，that our master was wearing his fine green coat and his black silk cap．（3）当that从句是双宾语中的直接宾语时，that不可省。
如：I can’t tell him that his mother died．2．由特殊疑问词引导的宾语从句这样的宾语从句实际上是由特殊疑问句变化而来的，宾语从句要用陈述句语序。
用于这种结构的动词常常是：see，say，tell，ask，answer，know，decide，show，find out，imagine，suggest，doubt，wonder，discover，understand，inform，advise等。
I can’t decide which book I should buy．3．由whether（if）引导的宾语从句I wonder whether（if）they will come to our party．由whether（if）引导的宾语从句，实际上是一般疑问句演变而来的。
意思是“是否”。
宾语从句要用陈述句语序。
一般说来，在宾语从句中whether与if可以互换使用。
4．宾语从句后带有宾补时，需用it作形式宾语，而把宾语从句放在句后，这时that不省略。
例如：He thought it wrong that they left the child alone at home．【表语从句】在句子中作表语的从句叫做表语从句。
引导表语从句的词有连词that，whether；连接代词who，what，which；连接副词when，where，how，why以及其它连词as if，as though，because等。
例如：The question is whether it is worth reading．They are just what I want．That’s why they were late．1．含有表语从句的复合句中的主语通常是fact，truth，explanation，problem，opinion，view等。
如：The fact is that fish can't go without water．事实是鱼离开水不能存活。
2．as if （as though）也可以用于表语从句。
但多是以下面形式出现。
主语＋look（seem）as if＋从句如：It looked as if it was going to snow．It seems as if there will be a quarrel soon．注意：不用if 引导表语从句。
reason做主语时，表语从句应由that引导，不用because。
that 引导表语从句时，通常不能省略。
专项练习1．— I flew to New York for the talk show on TV last week．— Is that ______you had a few days off?A．why B．when C．what D．where2．I ask her _____ come with me．A．if she will B．if will sheC．whether will she D．will she3．It was a matter of _______ would take the position．A．who B．whoever C．whom D．whomever4．Can you tell me ________?A．who is that gentleman is B．that gentleman is whoC．who that gentleman is D．whom is that gentleman5．Can you tell me ________ the railway station?A．how I can get to B．what can I get toC．where I can got to D．where can I get to6．It is generally considered unwise to give a child ________ he or she wants．A．however B．whatever C．whichever D．whenever7．Do you know ________ ?A．what is his name B．how is his nameC．what his name is D．how his name is8．Go and get your coat．It's________ you left it．A．there B．where C．there where D．where there9．I wonder how much ________．A．does the watch cost B．did the watch costC．the watch costed D．the watch costs10．It was _____ he said _____ disappointed me．A．what；that B．that；thatC．what；what D．that；what11．"Is Mary from New York City?" "I don't know _______．"A．from what city does she come fromB．from what city she comeC．what city does she come fromD．what city she comes from12．Henry killed the dog．I'll ask him why ________．A．did he do that B．he did thatC．he did D．he has done so13．Have you seen Henry lately? My boss wants to know ________．A．how he is getting alongB．how is he getting alongC．what he is getting alongD．what is he getting along14．I am sure ________ he said is true．A．that B．about that C．of that D．that what15．You can’t imagine ________ when they received these nice Christmas presents．A．how they were excited B．how excited they wereC．how excited were they D．they were how excited16．Why the explosion occurred was ________ the laboratory attendant had been careless．A．for B．because C．since D．that17．We gave him ________ help we could．A．which B．what C．that D．this18．Excuse me would you please tell me ________?A．when the sports meet is taken placeB．when is the sports meet going to be heldC．when is the sports meet to beginD．when the sports meet is to take place19．This book will show you ________ can be used in other contexts．A．how you have observedB．how what you have observedC．that you have observedD．how that you have observed20．Where do you think ________?A．has he gone B．has he been C．he's gone D．was he参考答案：1．A 由句子结构得知，空白处应选能在表语从句中作状语的连接副词，A．B．D．三个答案均能满足这一要求，但根据句意应选A，why为连接副词，在表语从句中作原因状语。
