clause) 一． 定义
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···）
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。
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if。
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.
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.
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。
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
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。
第一组： 1.---I drive to Zhuhai for the air show last week. ---Is that __you had a few days off? (NMET1999) A. why B. when C. what D where 分析：选 A Why 引导的表语从句中，why 做原因状语。 2. The question is ____it is worth visiting. A. if B. as if C. whether D. how 分析：选 C whether 引导表语从句 3. This is _____it happened. A. what B. when C. that D. how 分析：选 D how 引导表语从句，说明事情的发生经过。 4. This is ____ the city lies. A. which B. what C. where D. when 分析：选 C where 引导表语从句，表示城市所处的位置。 5. He was ill .That is ____he didn’t come yesterday. A. when B. why C. how D. that 分析：B because 引导表语从句，表示原因。 6. That was ___ I was thirteen I entered the No.1 Middle School. A. because B. why C. how D when 分析：选 A because 引导表语从句，表原因。 第二组： 1. The problem is ____we can master modern science and technology in a short time. A. if B. that C. what D. how 2. –-- Doesn’t Mr. Smith live on this street? --- No .This is ____Mr. Brown lives. A. which B. where C. how D. that 3. The reason why he has been such a success is ____he never gives up. A. what B. where C. how D. that 4. ---- What is that building? --- ___the garden equipment is stored A. that’s where B. There is in which C. the building is D. That’s the building which 5. Our village is no longer ____over twenty years ago. A. what was it B. what it was C. the village what was D. what was the village 6. ___you are the first one here. A. it seems that as if B. it seems as if that C. it seems as if D. It seems that as though 7. My hope is ___he will become a doctor in the future. A. if B. whether C. that D. what 8. It was ___they were used as an advertisement for the shop . A. because B. which C. what D. if 1-5 DBBAB 6-8 CCA
第三组： ［考题 1］ The traditional view is ____ we sleep because our brain is “programmed” to make us do so. (2007 上海) A. when B. why C. whether D. that ［答案］ D ［解析］ 下划线处之后是包含一个原因状语从句的表语从句，如果看不出它是充当整个句 子结构的表语从句将难以把握整个句子的意思。 因此， 应选择可引导名词性从句且不充当任 何成分的 that。 ［考题 2］ You are saying that everyone should be equal, and this is ____ I disagree. (2004) A. why B. where C. what D. how ［答案］ B ［解析］下划线处的引导词引导系动词 is 后的表语从句并在该表语从句中充当地点状语 (“disagree”属于不及物动词， “I disagree”本身是完整的主谓结构)， 下划线应填入 引导词 where， 表语从句“where I disagree”的意思是“我不同意之处、 我不同意的地 方” 。 ［考题 3］ — I drove to Zhuhai for the air show last week. — Is that ____ you had a few days off? (1999) A. why B. when C. what D. where ［答案］ A ［解析］下划线处的引导词引导与系动词 is 连用的表语从句并在该表语从句中充当原因状 语，下划线应填入表示“因此??”(指因某种原因所造成的结果)的引导词 why。 ［考题 4］ ____ she couldn’t understand was ____ fewer and fewer students showed interest in her lessons. (2000 上海) A. What; why B. That; what C. What; because D. Why; that ［答案］ A ［解析］ 第一个下划线处的引导词引导主语从句并在该主语从句中充当宾语，特指她所不 理解的事情，应填入关系代词型的引导词 what；第二个下划线处表示“因此??”(指因某种 原因所造成的后果，由 why 引导对应的名词性从句)而不是“为什么??”(指原因、 理由， 由 because 引导对应的名词性从句)， 应填入引导词 why。 ［考题 5］ ____ made the school proud was ____ more than 90% of the students had been admitted to key universities. (2003 上海春) A. What; because B. What; that C. That; what D. That; because ［答案］ B ［解析］ 第一个下划线处的引导词引导主语从句并在该主语从句中充当主语，特指令校方 骄傲的事情，应选用关系代词型的引导词 what； 第二个下划线处引导表语从句表示原因、 理由，应由 that 引导对应的名词性从句。 ［考题 6］ — Are you still thinking about yesterday’s game? — Oh, that’s ____. (2003 北京春) A. what makes me feel excited B. whatever I feel excited about C. how I feel about it D. when I feel excited ［答案］ A ［解析］ A 选项的意思是“令我感觉激动的事物” B 选项的意思是“我觉得激动的任何事 ； 物” C 选项的意思是“我对它感觉的方式” D 选项的意思是“令我感觉激动的时间” ； ； 。四 个选项中 A 最适合跟代表“game”的主语 that 对应，充当表语从句。