各種從句
I．要點
根據從句在句中的句法功能，從句可分為名詞性從句、定語從句和狀語從句。
1、名詞性從句
（1）主語從句
What he wants is a piece of paper.
It is believed that he can solve the problem.
注：主語從句的謂語動詞用單數。
（2）賓語從句
I don't know how to solve the problem.
Do you know where he lives?
（3）表語從句
The problem is who can help me.
This is why I came here.
（4）同位語從句
I have no idea where he went.
I heard the news that he would come.
同位語從句用that引導，常跟在fact, idea, news, promise, thought, message, hope, belief, doubt等詞后，that在從句中不作任何成分。
2、定語從句
在復合句中，修飾某一名詞或代詞，或修飾整個主句的從句叫做定語從句，引導定語從句的關系代詞有who, whom, whose, which, that, as,和關系副詞when, where, why。
（1）that指物時一般可與which互換，但在下列情況下，要用that而不用which。
a. 先行詞有all, everything等不定代詞時，如，
Everything (that) he did is wrong.
b. 先行詞被all, every, no, some, any, little, much等修飾時，如，
I'll read all the books (that) you lend me.
c. 先行詞被序數詞或形容詞最高級修飾時，
This is the first letter (that) the boy has written.
d. 先行詞被the only, the very, the same, the last修飾時，如
He is the very man (that) I'm looking for.
e. 只用which的情況
在介詞后或在非限定性定語從句中
This is the book about which we have talked a lot.
The book, which he gave me yesterday, is very interesting.
f. where和when作關系副詞
This is the room where I worked.
This is the room which I stayed in.
I remembered the day when we lived there.
I remembered the day that I spent there.
g. as和which
as 可以放于句首，而which 不可以
As you know, he is good at English.
three of them 和three of which
I have a lot of books, three of which are in Russian.
I have a lot of books and three of them are in Russian.
3、狀語從句
在復合句中起狀語作用的從句叫做狀語從句。狀語從句可分為時間狀語、地點狀語、原因狀語、目的狀語、結果狀語、條件狀語、行為方式狀語、比較狀語、讓步狀語等多種。
II．例題
例1、_______ I accept the gift or refuse it is none of your business.
A. If B. Whether C. Even if D. No matter when
解析：該題答案為B。whether可以和or連用，if不可以，此外if一般僅用于賓語從句。
例2、The way _______ these comrades look at problems is wrong.
A. where B. in that C.X D. with which
解析：該題答案為C，先行詞是way，定語從句中用that或in which來引導或不填。
例3，____a long time since I saw you last time.
A．It was B. It is C. It had been D. It can be
解析：該題答案為B，It is +時間數+ since引導的從句是一個句型，意為"從…時候以來過了多久了。"
