表语从句一． 定义表语：说明主语的性质、特征、状态或身份，说明主语是什么或者怎么样总之表语是对主语的解释和说明，是主语具体化，并且常与连系动词一起使用This book looks expensive. (形容词做表语)We are Chinese. (名词做表语)表语从句：在复合句中作表语的从句, 就叫做表语从句表语从句一般放在系动词之后,结构是“主语+系动词+表语从句”连系动词：be动词、表示持续的系动词（keep, remain, stay）、感官动词feel(摸起来，感觉) , smell(闻起来) , sound(听起来) , taste(尝起来，吃起来) 等、表示变化的系动词（become, grow, turn, fall, get, go,）、表终止的系动词prove, turn out(结果是，证明是)、seem, appear（看起来···）连系动词通常不用于被动语态和进行时态中He has become what he wanted to be ten years ago. 他已经成为了他10年前想成为的His suggestion is that we should stay calm. 他的建议是，我们应该保持冷静。
二．表语从句的引导词1.从属连词：that / whether /as if /as though/as/because(1) that引导表语从句本身没有词义，在句中只起连接作用，不充当句子成分，一般不能省略That fact is that more than seventy percent of the earth’s surface is covered by water.连接词that一般不能省略，但当主句中含动词do的某种形式时，that可以省略What I want to do is (that) I can go up to him and thank him. 我想做的事是走到身边去感谢他2) whether引导表语从句表示“是否”,但不充当句子的成分The question is whether we can finish our work by tomorrow evening.if 与whether均意为“是否”，但引导表语从句时，只能用whether, 不能用if3)as if/though“好像”，引导表语从句时要注意语态.如果句中的情况与事实不相符，从句多用虚拟语气。
如果从句表示与现在事实相反,谓语动词用一般过去式；如果从句表示与过去事实相反时,谓语动词要用“had + 过去分词 ”，如果从句表示将来的可能性不大，用would (might ,could )+动词原形.Li Lei is now in a new jacket. He looks as if he were an American boy. (现在事实相反)The girl is giving us a vivid description of the moon. It seems as if she had been to the moon many times. （与过去事实相反）It looks as if it might rain. （与将来事实相反）但是，如果as if/though引导的表语从句所表示的与事实相符，从句则用陈述语气The clouds are gathering. It looks as if is going to rain.(4) as引导表语从句He looked just as he had looked ten years before.他看起来还与十年前一样。
5) because引导表语从句常用结构：This/That/It is/was because····That is because I don’t like Chinese.2.连接代词：who/whom/whose/what/which/whoever/whatever/whichever/whomever，在表语从句中做主语、宾语、表语和定语Tom is no longer what he used to be. (what做表语)The problem is who is fit for this job. (who做主语)This is what I want to tell you. (what做宾语)The problem is whose work is the best. (whose做定语)3.连接副词：when/where/how/why，在表语从句中做状语The question is how he did it. 问题是他是如何做此事的The question is where we can live. 问题是我们能住在哪儿三． 注意一．reason做主语或主语中包含事件的起因时,后面的表语从句表示原因时要用that来引导,而不用because；why引导主语从句做主语时，表语从句用that引导，不用because。
The reason is that he got up late.Why he is late is that he got up late.二. that is why/because(1) That is why ...是常用句型,其中why引导的从句在句中作表语,该句型通常用于针对前面已经说过的原因进行总结That is the reason why ...与That is why ...是同义的，“这就是……的原因/因此……”，但是从语法结构上讲That is the reason why ...中的why引导的是一个定语从句That is why she failed to pass the exam. 那就是她考试不及格的原因why 在表语从句中充当原因状语) That is the reason why she failed to pass the exam.那就是她考试不及格的原因why 在定语从句中充当原因状语) (2) That is because···句型中从属连词because引导的名词性从句在此作表语，这也是个常用句型，意为“这就是因为……”That is because I got up late. 这是因为我起床迟了。
3) “That is because...”与“That is why...”之间的不同在于“That is because...”指原因或理由， “That is why...”则指由于各种原因所造成的后果I was angry. That was because he didn’t understand me.我生气是因为他不理解我表语从句强调原因)That’s why he got fired from that firm.那正是他被公司解雇的原因表语从句强调结果)三. The reason (why…/for…)is /was that…. ···的原因是····The reason for his absence is that he got up late.The reason why he is absent is that he got up late.他缺席的原因是他起床迟了四. 使用虚拟语气的表语从句在表示建议、劝告、命令、计划含义的名词后的表语从句，谓语动词需用“should+动词原形”表示虚拟语气，should可省略常见的词有：advice，suggestion，order，request，proposal，plan，idea等。
My suggestion is that we （should） start early tomorrow.我的建议是我们明天一早就出发牛刀小试1.系动词出现于单项选择题中 ①The story sounds_________________(MET 89) A. to be true B. as true C. being true D. true②Those oranges taste__________(MET 91) A. good B. well C. to be good D. to be well③---Are you feeling___________ ---Yes, I’m fine now/(NMET92) A. any well B. any better C. quite good D. quite better④----Can I join the club, Dad. ----You can when you _________a bit older.(NMET 94) A. get B. will get C. get D. will have got ⑤---Do you like the material ----Yes, it _______very soft.(NMET 94) A. is feeling B. felt C. feels D. is felt⑥I love to go to the seaside on Summer. It_____ good to lie in the sun or swim in the cool sea.(NMET 96) A. does B. feels C. gets D. makes⑦Cleaning women in big cities usually get _______by the hour.(NMET 98) A. pay B. paying C. paid D. to pay⑧Why don’t you put the meat in the fridge It will _____ for several days.(NMET2003） A. be stayed B. stay C. be staying D. have stayed 2.系动词巩固练习 ①What you have said_______. A．is sounded interesting B sounds interestingC．sound interested D．listens interested ②The class begins. Please keep________. A．silent B．silence C．the silence D．silently ③Look! Several people in the crowd seemed_______. A．to be fighting B．to have fought C．being fought D．having fought ④How _____the song she sings sounds! I have never ______a better voice. A．beautifully, sounded B．beautiful, sounded C．sweet, listened to D．sweet, heard ⑤Her feeling about the marriage。