二、高中语法—【表语从句】详解

高中英语表语从句详解

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if。

(3)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 werean
American boy. (现在事实相反)

The
girl is giving us a vivid description of the moon. It seems as if shehad
been tothe moon many times. （与过去事实相反）

It

looks as if itmight
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。

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.

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。

1、概述

用作表语的从句叫作表语从句，它位于主句中的连系动词之后。引导表语从句的词有从属连词that、whether、as
though(if)；关系代词who,
what, which, whom, whose, whatever, whoever, whomever,
whichever等；关系副词when,
where, why, how, however, whenever, wherever等。可以接表语从句的连系动词由be,
look, remain, seem等。That引导表语从句时，在口语中，间或可以省略。

The
trouble is that we are short of money.困难是我们资金短缺。

That
is why stone walls are used instead of fences around New England
fields.这就是为什么在新英格兰用石头墙而不用栅栏的原因。

At
that time, it seemed as if I couldn't think of the
right word anyhow.当时,我似乎怎么也想不出一个恰当的字眼来。

2、由从属连词that，whether引导的表语从句。

that在引导表语从句时无词义，而whether有词义，意为、“是否”。这时主句的主语常常是些抽象名词，如question(问题)，trouble(麻烦)，problem(问题)，result(结果)，chance(可能性)，suggestion(建议)，idea(想法)，reason(理由)等。表语从句对主句主语进行说明、解释，使主语的内容具体化。

The
trouble is (that) she has lost his money. 麻烦的事是他丢了钱。

The
question is whether we need more ice
cream.问题是我们是否还需要一些冰淇淋。

The
problem was that it was too valuable for everyday
use.问题是它作为日常之用太贵重了。

What
she couldn’t understand was that fewer and fewer students
showed interest in her lessons. 我们不能理解越来越少的学生对他的课不感兴趣。

3、由关系代词引导的表语从句。

关系代词who,
what, which, whom, whose, whatever, whoever, whomever,
whichever等引导表语从句，在句中作主语、宾语、表语，关系代词不能省略。

The
question is which of us should go.问题是我们哪一个应该去。

The
problem was who could do the work.问题是谁能做这项工作。

That's what
he is worrying about.那就是他在担心的事。

That's what
we should do.那是我们应该做的。

4、由关系副词引导的表语从句。

Go
and get your coat. It's where you left it. 去把雨衣拿来。就在你原来放的地方。

I
had neither a raincoat nor an umbrella. That’s why I got wet
through. 我们既没伞也没雨衣，这是我们淋湿的原因。

That
is how mice ruin many stores of grain every
year.那就是老鼠是怎样每年损害大量粮食的。

That
is what he is worried about.那就是他所担心的。

5、由连词because，as

if/as though等引导的表语从句。

It
looked as if it was going to snow.看起来好像要下雪了。

That's because
we never thought of it.这是因为我们从未想过此事。

It
seems as if he didn’t know the answer.好像他不知道答案。