定语从句需特别注意的地方
situation, case, point在从句中充当状语时，后常用where
Can you think of a situation where you can use the word?
标点符号，比较以下一组句子：
I picked up the apples. Some of them were bad.
I picked up the apples; some of them were bad.
I picked up the apples and most of them were bad.
I picked up the apples, some of which were bad.
关系词选择时，要注意从句中的及物动词和不及物动词，从而判断先行词在从句中所作的成份。特别是看到先行词是时间、地点、原因时，要特别小心。注意下面几组句子：
I’ll never forget the days when/in which we worked together.
I’ll never forget the days that/which we spent together.
I went to the place where/at which I worked ten years ago.
I went to the place that/which I visited ten years ago.
This is the reason why/for which he was late.
This is the reason that/which he gave.
which和whose在从句中做定语时的区别:
He told me the tickets are hard to buy, in which case you’d better buy right now.
(which作case的定语)
He advised me to hide behind the door, which advice I took at once. (which作定语)
The book (whose cover is missing) is very funny. (不可分割的一部分, 指物时可用of which来代替)
The room (whose door faces south) is very bright. (物质所属)
which做定语时和后面的名词一起指代前面的先行词（通常为整个句子），还原从句为独立分句时，往往还原成this/that；如第一句which case指代前面的句子，从句可还原成In that case, you’d better buy right now. 第二句：I took that advice at once.
而whose做定语时只是单独指代前面的先行词，通常可以用of which 或of whom来代替，还原时往往变为its/his/…等。比如第三句：The book is very funny and its cover is missing.
分裂式定语从句：有些定语从句的先行词和关系词之间会插入一些其它成份。He arrived in Jinzhou in 1984, where he became a manger 2 years later. 此句中关系词不能用when，因为从句中已经有时间状语，因此先行词不是1984，而是Jinzhou。
带有插入语的定语从句，如I think, do you suggest等。
Please choose someone who you think is kind. 此句中you think为插入语，关系代词who作从句的主语，is是从句的谓语。
介词from后可以跟where
He has been to the city twice from where his girl friend came.
定语从句和同位语从句的区别。定语从句的先行词或关系代词要在从句中充当一定的句子成份，而同位语从句中则不充当任何句子成份，比较以下两个句子。
The news that our team lost the game disappointed all of us. 此句为同位语从句，the news在从句中不充当任何句子成份。
The news that you told me yesterday is so disappointing. 此句为定语从句，the news在从句中充当宾语。
定语从句和状语从句的区别，状语从句没有先行词，引导词用where，它很明显的特点是其前面为动词、副词等，有时虽有名词但不是表示地点的名词。
You should make it a rule to leave things where you can find them again.状从
After the war a new school building was put up where there had once been a theatre. (状语从句)
This is the room where/in which we lived three years ago.定从
定语从句和强调句的区别
强调句型的结构：It is / was (could be…) + 被强调的成分 + that ...
强调的成分是主语、宾语和状语。强调句型可用“还原法”来判断，若删除强调句型结构后，句子能还原为一个完整的句子，就是强调句。
It was at the school gate that I met Tom yesterday.
It was the school gate where I met Tom yesterday.
第一句为强调句，去掉强调句型结构后，句子可以还原成一个完整的句子，I met Tom yesterday at the school gate. 而第二句不能还原成一个完整的句子，必须要加个介词at。
as前置和It作形式主语的主语从句混淆
这两种形式主要区别在于as结构有标点符号“，”号，而It和that连用，比较下面两个句子：
As is known to all, the earth moves around the sun.
It is known to all that the earth moves around the sun. |
