定語從句（Attributive Clauses）在句中做定語，修飾一個名詞或代詞，被修飾的名詞,詞組或代詞即先行詞。下面是小編為你帶來的英語定語從句說課稿 ，歡迎閱讀。

一， 定義：在復合句中作定語，修飾主句中某一名詞或代詞的從句，叫做定語從句。被定語從句所修飾的詞叫先行詞，通常位于定語從句前。引導定語從句的是關系代詞（that,which,who,whom,whose）和關系副詞（when,where,why），它們既起連接作用，又充當從句中的一個成分，如何使用關系代詞或副詞是根據先行詞及其在從句中所充當的成分確定的。

二，關系代詞引導的定語從句

　　注：如果關系代詞在從句中作主語，從句謂語動詞的人稱和數必須和先行詞一致。

　　①China is a big country that/which has a history of about 5000 years.

　　②Phil who/that comes from England is an active boy.

　　③The doctor (who/whom) David saw at the hospital told me to stop smoking.

　　④We passed some shops whose windows were decorated for Christmas.

　　⑤Is this the book (that/which) he is looking for?

　　△重點

　　1.that,who和which在從句中作主語時不可省略，作賓語時可省略。（但whom/which前有介詞時，whom/which不能省略）

　　e.g. The man (who/whom) my father is talking with is my teacher.

　　The man with whom my father is talking is my teacher.

　　2．關系代詞在從句中作介詞賓語時可跟介詞一起放在先行詞后面；為了使關系代詞緊跟它所修飾的先行詞，也可把介詞放在從句中有關動詞的后面。但固定短語中的介詞不要放在先行詞前（如look for,look after,take care of等）

　　e.g. The boy who(m) she is looking after is her aunt’s child.

　　3.that與which先行詞都可指物，that與who/whom先行詞都可指人，很多情況可互換使用，但也有區別。

　　A.只用that不用which的情況

　　1）當先行詞是指物的不定代詞all,much,little,something,everything,anything,nothing,none,the one時。

　　e.g. I’m interested in everything that I don’t know.

　　2)當先行詞被(the)only,the very,the last,all,some,any,no,every,little,few,much等修飾時。

　　e.g. There is no difficulty that we can’t overcome.

　　3)先行詞前有序數詞、形容詞最高級修飾時或先行詞本身就是序數詞或形容詞最高級時。

　　e.g. The first lesson that we’re going to learn is very difficult.

　　4)先行詞為兩個及兩個以上分別表示人和物的名詞時。

　　e.g. We know nothing about the doctors and the hospitals that you are talking about.

　　5)當主語是以who或which開始的疑問句時。

　　e.g. Who is the boy that was here just now?

　　6)關系代詞在定語從句中作表語時。

　　e.g. The village is no longer the poor place that it used to be.

　　7)先行詞有the same修飾，先行詞和關系代詞指同一物時。

　　e.g. This is the same pen that I used yesterday.

　　B.只用which不用that的情況

　　1）關系代詞前有介詞時。

　　e.g. This is the room in which we lived last year.

　　2)引導非限制性定語從句時。

　　e.g. His dog,which was very old,became ill and died.

　　3)先行詞后有插入語時。

　　e.g. Here is the grammar book which,as I’ve told you,will help improve our English.

　　4)先行詞本身是that時。

　　e.g. What’s that which flashed in the sky just now?

　　C.先行詞指人，但只用who不用that的情況。

　　1）先行詞是指人的不定代詞時，如one,someone,anyone,no one,all,nobody,none,those等。

　　e.g. Those who are against put up your hands.

　　2)當先行詞是一個限定性的表示人的特定名詞時。

　　e.g. The aunt who came to see me last week is my father’s sister.

　　3)當先行詞有較長的后置定語或在被分割的定語從句中。

　　e.g. Mr.White is coming soon who will give us a talk.

　　4)whose+n.=the+n.+of which/whom

　　e.g. We live in the room,whose window is broken.(=the window of which is broken.)

　　注意：which與whose作定語時的區別

　　which只用于非限制性定語從句，僅指物，且要修飾對先行詞起概括作用的泛指名詞；“whose+n.”與先行詞不表示同一事物或情況。

　　e.g. ①Mary is studying Chinese,which knowledge is important now.

　　②The man whose wife is a housewife is from France.

　　△難點：關系代詞as引導的定語從句

　　as既可引導限制性定語從句，也可引導非限制性定語從句，as在從句中作主語、賓語或表語。

　　引導限制性定語從句，常用于以下句式。

　　1） such+n.+as…：“像….一樣的”

　　the same+n.+as…：“和…同樣的”（指同類異物，同類同物用that）

　　e.g. ①These houses are sold at such a low price as people expected.

　　② I want to buy the same cellphone as you bought.

　　The same customer that came here yesterday is here again.

　　2)…such as…

　　such意為“這樣的人或物”，修飾先行詞such.

　　e.g. This book is not such as I expect.

　　關系代詞as與which引導非限制性定語從句的區別：as引導的非限制性定語從句，既可在主句前，又可在主句后，有時還可插入主句中，而which引導的'非限制性定語從句只能置于主句之后。相同的是兩者都可替代主句的整個內容，而不是主句中的某一個詞。

　　e.g. ①As is known to everybody,the moon travels round the earth once every month.

　　3．當定語從句放在主句后面時，也并非as永遠等于which。

　　1）當非限制性定語從句是否定句或表示否定時只用which。

　　e.g. He came here very late,which was unexpected(not expected).

　　2） 當as在從句中作主語時，后面常跟動詞的被動式。如be known,be said,be reported,be announced等。若從句中動詞是主動式，一般用which作主語。

　　e.g. ①She’s been absent again,as is expected.

　　②Tom has made great progress,which makes us very happy.

　　3)當非限制性定語從句的謂語是一個復合結構時，只能用which引導定語從句。

　　e.g. Betty always tells a lie,which her parents find strange.

　　4)as多用于下列習慣用語中：

　　as anybody can see as is well-known=as is known to all

　　as we had expected as often happens

　　as has been said before as is mentioned above

　　as (it) seems likely as (it) pointed out

　　as I remember (it) as I understand (it)

　　as (it) appears

　　e.g. Jack has won the first prize,as it often happens.