形式主语和强调句式的区别?

that是英语中非常活用的词，其用法很多。现在重点谈谈that在各类复合句中的
用法及它们之间的区别。that作连词可引导名词性从句，状语从句，构成强调句
；作关系代词可引导定语从句。
I、that在定语从句中的用法
that引导定语从句时，它前面的先行词既可指人也可指物，that在定语从句中可
作主语、宾语或表语，作宾语时that可省掉，作主语或者表语时不能省。
例：He's the man that(who) lives next door.（作主语，先行词指人还可用w
ho）
Is that the address that(which) you sent the telegram
to?（作宾语，先行
词指物还可用which）.
但在下列情况下关系代词that不用which.
1）表物在先行词前面有序数词或最高级修饰时
例：It's the most expensive book that I have bought.
2）当先行词为anything, everything, nothing, all, little,
much等时
例：All that glitters is not gold.
3）表物的先行词前all, every, the only, the very, the last, much,
littl
e 等修饰时。
例：It's the only storybook that we have read this year.
4)先行词既指人又指物时
例：They talked about the people and thing that had seen
in Britain.
5）当关系代词在定语从句中作表语时，先行词不管指人或指物时都只用that。
例：1、My typewriter is not the machine that it used to be.
2、Dr Smith still talks like the man that he was ten
years ago.
6）当先行词前有the same 修饰时，如果表示同类不同一时用as，如表示同一人
或物时用that。
例：1、I have bought the same dictionary as you did last
week.
我买了一本与你上周买的相同的词典。（指两本相同的词典）
2、Tom is my classmate. He studies in the same room that
I study in.
汤姆是我的同班同学，他和我在同一个教室学习。（这里指的是同一个教室）。
7）当主句是It is the first/second time 时后常用that引导从句而不用when。
例：It's the second time that we visited the Great Wall.
II.that在名词性从句中的用法
that作连词可引导主语从句，宾语从句，表语从句和同位语从句。在这四类从句
中，that在从句中不充当任何成份，无意义，仅起连接作用。引导宾语从句中th
at常可省去，引导主语从句、表语从句和同位语从句时一般不省。
一、that在主语从句中的用法
that引导主语从句时，常用it作形式主语，把真正的主语从句放在句末，以求句
子平稳，也可把that从句直接放在句首，这时that绝对不能省去。如果that引导
的主语从句在疑问句中时，必须用it作形式主语。
例：1）It was obvious that the driver could not control the
car.(that有
时可省)
2）That the driver could not control the car was
obvious.(that绝不能省
)
3）Is it possible that they will finish the project in
such a short ti
me?(必须用it作形式主语)
二、that在宾语从旬中的用法
1、that引导的从句常作动词宾语，这时that常可省去，如果从句后有宾语补足语
时，常用it作形式宾语，把that从句放在句末。
例：1)The boy dreamed(that)he was flying to the moon．
2)We don't doubt that he's honest．
3、They want to make it clear that they are doing a
important job for
US．
2、当主句谓语动词是表示“相信”，“臆测”等动词，如believe，suppose，e
xpect，imagine，think等时其后作宾语的that分句如果带有否定意义通常要将n
ot移至主句，即否定转移。
例：I don't think anyone will object to the plan.
3、that引导从句除可作介词except等，宾语之外般不可以直接用作其它介词宾语
，但可用it作形式宾语，把that从句放在it之后。
例1)His composition is very good except that there are
some spelling m
istakes．
例2)Can you depend on it that they will supply us with
any food?
三、that在表语从句的用法that引导的从句放在联系动词后作表语，以说明主语
的内容。that一般不省，但在非正式文体中时也可省去。
例：The fact is that he didn't notice the car until too
late．
当主语是reason时，应用that引导表语从句不可用because.
例：Tom was late again．The reason is that he had missed
the early bu
s．
四、that在同位语从句中的用法
that引导的从句常可放在名词fact，idea，promise，belief，decision，news，
problem，word等后面，常用于说明该名词的实际内容，起补充作用，而不是起修
饰或限制作用。that在从句中不充当任何成分，无意义。如主句谓语较短时，常
可把从句放在句尾，以保持句子平衡。
例：1)They had to face the fact that the nearest filling
station was
thirty kilometers away．
2)Word came that our“soldiers had defeated the enemy
brave1y．
Ⅲ．That在状语从句中的用法
l、that引导的从句常可放在表示思想状态或感情色彩的形容词之后作状语，表明
原因或理由。
例：1)We are glad that we have reaped another bumper
harvest．
2)We are surprised that she should behave like that．
2、that可与so，in order，fo rfear连用引导目的状语从句，这时从句中常含有
情态动词could，can，might，should等。
例：1)He explained again and again in order that we could
understand
him．
2)I hid the book for fear that he should see it．
3、that可与so，such搭配引导结果状语从句，但要注意它们的用法区别。
So(1)adj/adv
(2)adj+a/an+单数可数名词
+that从句
(3)many/few复数可数名词
much/tittle不可数名词
such(1)a+复数可数名词，不可数名词
+that一从句
(2)a/an+adj+单数可数名词
例：1)He was so tired that he could not walk any farther．
2)This is so interesting a book that we all want to read
it．
3)Such little sheep have eaten so much grass that we
can't believe it．
当so such引导短语放在句首时，句子要部分倒装。
例：I)So badly was he injured that he had to go to the
hospital.
2)In such a hurry did he go to school that he forgot to
bring his scho
olbag．
IV．that在强调句式中的用法
that可以用于It is／as+被强调部分+that句式中，被强调部分可以是句子的主语
，宾语，状语，宾语补足语，但不能是谓语或表语。在强调句子某一部分时，把
该部分放在that之前，句子的剩余部分原样放在that之后，一般不作变化。
例：I am going to take part in the football match on the
playground ne
xt Sunday afternoon．
1)强调主语I
It is I that(也可用who)am going to take……
2)强调on the playground．
It is on the playground that(不能用where)I am……
3)强调next Sunday afternoon，
It is next Sunday afternoon that I……
但在强调not……un句型时，注意not的位置变化
例：He didn't realized the importance of English until he
went abroad
．
It was not until he went abroad that he realized the
importance of En
glish.
V．that引导的各从句之间用法区别
一、that引导的定语从句与同位语从句的区别
that引导的定语从句与同位语从句都放在名词之后，但that引导定语从句时，它
代替前面的先行词在从句中作主语，宾语或表语，有一定的意义，定语从句对先
行词起修饰或限制的作用，而that在同位语从句中不充当任何成分，无意义，从
句主要是说明前面名词的内容。
例：1)I heard the news that some foreigners would come to
our school(同
位语从句，that不充当从句中的任何成分)。
2)I hear the news that made me
surprised(定语从句，that在从句中作主语)
3)The fact that the earth moves around the sun is
true．(同位语从句)
4)The fact that he told us yesterday is
true．(定语从句，that在句中作宾
语)
二、强调句与主语从句的区别
that引导的主语从句可直接放在句首，而强调句不能，把强调句中的It is／was
that删去剩下的句子位置稍作改变或不变仍为一个完整句子，而主语从句则不能
。
例：1)It's surprising that Mary should have won the first
place．
2)It's Mary that has won the first place．
第一句为主语从句，这里it作形式主语也可把that从句直接放在句首，句子结构
也正确。第二句为强调句，如把that后的句子放在句首，则句子结构不正确，如
省去It's…，that后句子的剩余部分依然正确，故为强调句。
又如：①It's a good idea that“we'll make an experiment in
the lab．
②It's a good idea that he has told us．
第一句为主语从句，第二句为强调句。
三、强调句与定语从句区别比较下列两句
It is money that is most needed．
This is the money that is most needed．
第一句为强调句，其中的that并不是money的后置修饰语，第二句为定语从句，修
饰前面的瑚money.
又如It is Mary that has won the first place。
Mary is the girl that has won the first place．
第一句为强调句，第二句为定语从句。
定语从句的先行词常是名词词组，很少用人称代词，而在强调句中被强调部分可
是人称代词，介词词组，副词词组或从句等。
例如1)It was he that stole my bike．
2)It was in the street that the accident happened．
3)It was when it got dark that he came back．
四、强调句与状语从句区别
比较下列两句
It Was at six o'clock that we got home．
It Was six o'clock when we got home．
第一句是强调句，强调时间状语，如去掉It Was that剩下句子依然完整。第二句
为时间状语从句，it表示时间，译作当我们到家时，已是六点了。如为强调句，
去掉it Was that句子不成立，因为six O’clock不能作时间状语。
又如：
It was on February 12，1809 that Lincoln was born．
It was February 12．1809 when Lincolnwas born．
第一句为强调句，第二句为状语从句。