第三部分 从句
一.宾语从句：
1.主句若是一般现在时，从句根据实际情况用适当时态。
He says (that) he will have a walk soon.
The teacher asks who is the cleverest in the school.
I want to know who came here late this morning.
2.主句若是一般过去时，从句也要用过去时。
He wondered if I would come. She told me that her son had got well.
She said that she liked watching TV. We thought Jim was wrong.
3.无论主句是何时态，从句若表客观真理，要用一般现在时。
Mr. Li said the moon is smaller than the earth.
4宾语从句无论有何引导词，都要用陈述句语序。
Could you tell me when you will get back to Wuhan?（不是will you）
Do you know which sweater she is wearing? (不是is she)
二、状语从句：
1主句若是一般将来时、祈使句或含不表过去的情态动词等，则if(如果), unless(除非)，when(当…的时候), as soon as(一…就…)，before, after, until, till, as(当…的时候)所引导的状语从句用一般现在时。
You may take a rest when you finish doing your work.
I will call you up if I leave for Shanghai next week.
Wait for your brother at the bus station until he arrives.
2而主句若是一般过去时，从句也要用过去时，如：
I would give the money to the charity if I had a million dollars.
When he got to the park, his classmates had left.
My son ran towards me as soon as he saw me on the street.
三.定语从句：
关系代词who只指人，which只指物。that既可指人又可指物。whose 后必须跟有名词，既指人，也可指物。关系词作主语时，不可省略，作宾语时可省略。whom只指人，只作宾语。关系副词where指“在那里”，when指“在那时”。
She is a girl (who/whom/that) I know very well.
That boy whose hair is very long is my brother. (所属)
The girl who is tall is my sister. / I own a bike whose price is high.
I bought a watch (which/that) I paid 100 yuan for. （指物）
I prefer a place which/that is clean and quiet.
I prefer a place where I can live a quiet life. （在这儿）
I shall never forget the day when a boy helped me find my dog.
（1）that指物时一般可与which互换，但在下列情况下，要用that而不用which。
a. 先行词有all, everything等不定代词时，如，
Everything (that) he did is wrong.
b. 先行词被all, every, no, some, any, little, much等修饰时，如，
I'll read all the books (that) you lend me.
c. 先行词被序数词或形容词最高级修饰时，
This is the first letter (that) the boy has written.
d. 先行词被the only, the very, the same, the last修饰时，如
He is the very man (that) I'm looking for.
e. 只用which的情况
在介词后或在非限定性定语从句中
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作关系副词
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.
四、状语从句
在复合句中起状语作用的从句叫做状语从句。状语从句可分为时间状语、地点状语、原因状语、目的状语、结果状语、条件状语、行为方式状语、比较状语、让步状语等多种。
例题
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：该题答案为B。whether可以和or连用，if不可以，此外if一般仅用于宾语从句。
例2、The way _______ these comrades look at problems is wrong.
A. where B. in that C.X D. with which
解析：该题答案为C，先行词是way，定语从句中用that或 in which来引导或不填。
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：该题答案为B，It is +时间数+ since引导的从句是一个句型，意为"从…时候以来过了多久了。