定语从句与其他句型的区别

定语从句和同位语从句的三大区别

在考研英语的文章中，同位语从句和定语从句都放在被修饰词的后边，从形式上来看，它们十分相似，很多同学搞不清楚涉及到定语从句和同位语从句的相关知识点。为了减少大家在读文章时的相关障碍，老师现就同位语从句和定语从句的相关区别给大家做一个讲解。

（一）连接词作用不同。

以that为例，连接定语从句的that一定会在从句中充当一定的成分；而连接同位语从句的that只起连接作用，不在从句中担任任何句子成分。whether 和 how 可以引导同位语从句，但不能引导定语从句。关系代词和关系副词除了连接从句的作用外，还在定语从句中充当一定的句子成分，如主语、宾语、定语、表语等。引导定语从句的连接词是关系词，常见的关系代词和关系副词有

that , which , who , whose , whom , when , where , why , as，than, but等The fact that we talked about is very important.

The fact that he succeeded in the experiment pleased everybody.

（二）先行词不同。

定语从句先行词既可以是人，也可以是物。相当于形容词。

The moon is a satellite that goes round the earth.

The few points that the president stressed in his report are very important.

同位语从句进一步说明的是具有抽象概念的词，其作用相当于名词，对前面的名词进行补充说明。如fact, result, discovery，

belief , doubt , fact , hope , idea , news , possibility , thought , order , sugges tion , wish , answer , information , conclusion , decision , discovery , knowled ge , law , opinion , problem , promise , proof , question , report , truth , risk 等等。

He has an idea that he can make the scientific instrument in a better way. He expressed the hope that he would come to China.

（三）从引导词来看

如果引导从句的词为when表示时间，where表示地点，why表示原因，how怎么样，表示方式，而它前面的词分别表示时间，地点，原因，方式等意义，那它们就是关系副词，引导的是定语从句。

I’ll never forget the day when I saw the Great Wall.

This is the room where LuXun once lived.

The question when we will start the work is not decided.

You have no idea how worried I was.

强调句和定语从句都有哪些区别？

1. 强调句与主语从句的比较

强调句将句子中的it is / was…that同时省去，句子仍然成立；而主语从句将that与后面部分代替it，成立。如：

(1) It is Li Lei’s brother that you met in the street yesterday. 你昨天在街上所见到的就是李蕾的兄弟。

本句若将It is 及that同时省去为：You met Li Lei’s brother in the street yesterday. 句子同样成立，因此前面的句子是强调句型。

(2) It is exciting that we have succeeded in sending up Shenzhou V. 我们成功地发射了神舟五号这件事情真令人兴奋。

本句若将It is 及that同时省去为：We have succeeded exciting in sending up Shenzhou V. 显然句子错误，因此，前面句子不是强调句型，而是主语从句。

2. 强调句与定语从句的比较

◎强调句中的It没有实际意义，It be与that可同时被省略;而定语从句中的It是主语，It be与that不可同时省略;

◎强调句型中be的时态须跟后面句子的时态相一致;而定语从句中主句谓语动词be的时态须由主句的时间确定;

◎强调句将句子中的that不能省略，并且即使前面的名词是事物时，也不能将that换成which;而定语从句中的that作宾语时可被省略，并且当先行词是事物时可用which代替。

◎当it be后面的时间、地点名词作主语、宾语或表语时，引导词可用that / which;而作其他成分时，引导词须用when / which。如：

(1) It is an English book (that / which) I bought yesterday. 它是我昨天买的书。(本句是对What is that?问句的回答，that所引导的是定语从句，that可被省略)

It was the English book that I bought yesterday. 昨天我所卖的就是这本书。(本句相当于对I bought the English book yesterday中an English book进行强调)

(2) It was a room where we used to have meetings. 它是我们过去常在开会的房子。(where 所引导的从句对前面的room进行说明，它是定语从句)

It was in the room that we used to have meetings. 过去我们开会就在这间房子里。(in the room是被强调的部分，本句是强调句型)

(3) It is a day when the people celebrate their victory. 这是人们庆祝他们的胜利的日子。(when所引导的从句对a day进行说明，是定语从句)

It was on that day that people celebrated their victory. 就在那一天，人们庆祝了他们的胜利。(强调on October 1, 1949)

3.强调句与状语从句的比较

◎状语从句句首的It本身就是句子的主语;而强调句首的It不作任何成分也没有实际意义。◎状语从句的连接副词that及句子前面的It be不能去掉(from)。

◎状语从句的引导词可以是when / where，而强调句型中的that不能用其他词代替。如：

(1) It is such an interesting book that we all like it very much. 它是一本如此有趣的书，我们大家都非常喜欢。(结果状语主从复合句)

It is such an interesting book that we all like very much. 我们大家都非常喜欢的就是一本如此有趣的书。(强调such an interesting book)

(比较：It is such an interesting book as we all like very much. 这就是我们大家都非常喜欢的如此有趣的书。定语从句)

(2) It was already morning when he woke up. 当他醒来时，已经是早晨了。(时间主从复合句)

It was the next morning that he woke up. 就在第二天早晨他醒来了。(强调the next morning)