定語從句在句中作定語，修飾名詞或代詞，被修飾的名詞片語或代詞即先行詞。定語從句通常出現在先行詞之後，由關係詞(關係代詞或關係副詞)引出。 那麼怎樣判斷定語從句?下面我們去了解一下吧!
一、定語從句的識別：
名詞(句子)+連線詞+句子
其中識別度最高的關鍵之處，就是連線詞，它有三種：
① 關係代詞：who, whom, that, which, as, whose
② 關係副詞：when, where, why, how
③ 介詞+關係代詞：介詞+whom, 介詞+which, 介詞+whose
但注意，有時你會看到 in that，但in that=because，算是一種固定搭配，這和定語從句沒關係。
這裡單獨說一下as引導的定語從句吧，因為其它都還比較常見，as相對來說比較生疏。
主要是在same和such之後，定語從句用as引導，但偶爾the same後面也用that.
如：I've never heard such stories as he tells.
我從來沒聽到過他講的這種故事。
He is wearing the same suit as(或that) he wore at Mary's wedding.
他穿著與他在瑪麗的婚禮上穿的一樣的衣服。
二、定語從句的處理
原則：將定語從句完整地切分出來，獨立成句。
兩個關鍵點：① 完整地切分;② 獨立成句
第一步，切分：切分點在連線詞前，如果連線詞前有介詞那就在介詞前。
如：I love this girl / who is beautiful.
I went to Changchun / where I met my wife for the first time.
I have three books / of which the red is my favorite.
第二步，找指代(也就是關係代詞的指代物件)：
如：This is the expert / to whom we are turning.
注：turn to = resort to = 求助於……
這句話裡的關係代詞是 whom , 它的指代物件是the expert.
所以這句話翻譯過來是：這就是我們正在求助的那個專家。
第三步，調語序
需要調整語序的也就是關係代詞和(介詞+關係代詞)
還是上面那句話：This is the expert to whom we are turning.
先切分，① this is the expert /
② to whom we are turning
再找到第②句中whom的指代物件，whom=the expert
也就是 to the expert we are turning
這時落實到我們要講的調語序了，因為我們發現to the expert we are turning,它由於受到定語從句規則的限制，所以不是正常語序，現在我們把它變成正常語序就是：we are turning to the expert
這時，你再翻譯成中文時就沒有障礙了。
至此，我們總結一下，定語從句的處理就是分三步，1.切分;2.找指代;3.調語序
這樣就可以完成了將一個定語從句從英文到中文的轉換，所以下次遇到定語從句時，你只管先“咔嚓”來一刀，給它切開，兩個句子安安靜靜地出現在你面前，你就別麼費勁地去前置了，那麼定語從句就不能前置了嗎?也不是不能，語義如果挺順暢的.你就前置唄，只是能前置的定語從句基本上都退化成後置定語了，比如，an apple which is on the table也可以寫成an apple on the table(桌子上的蘋果)
a way which is to solve the problem也可以寫成 a way to solve the problem(解決這個問題的方法)
定語從句的幾個難點
難點一：定語從句與並列句的區別
觀察下面三個句子：
Hong failed in the College Entrance Examination, ________ disappointed his mother.
Hong failed in the College Entrance Examination and ________ disappointed his mother.
Hong failed in the College Entrance Examination; ________ disappointed his mother.
(提示：判斷是定語從句還是並列句，要注意句中的標點符號和句中的連線詞。)
例1：Tom’s mother kept telling him that he should work harder, but _____ didn’t help.
h
例2：The weather turned out to be very good, _____ was more than we expected.
h
e
例3：The mother told her lazy son to work instead of staying at home; ____ didn’t help.
h
難點二：介詞+關係代詞引導定語從句中介詞的選擇
“介詞+關係代詞”可引導限制性定語從句也可引導非限制性定語從句，可從以下幾點定位關係代詞前的介詞。
1.介詞與先行詞搭配是一種固定搭配
I still remember the day ____________ I first came to school.
The company ______________ I once worked has changed much.
2.介詞與從句中動詞的搭配
He is a man of great knowledge, _____________ much can be learned.
In the dark street, there wasn’t a single person _____________ she could turn for help.
3.介詞與從句中形容詞的搭配
China is a beautiful country, _____________we are greatly proud.
The teacher talked about some subjects _________________ the students were interested.
4.與名詞之間的搭配
He may be late, ________________ we ought to wait for him.(如果是這樣)
Call me at six o’clock, __________________ I should get up.(到那個時候)
Ex:
(1)There is a room, _______________________ faces the river.
那兒有一間房子，窗戶面對這條河。
(2)They are the very people _______________________ for help.
他們就是那些你可以向其求助的人。
(3)China has many islands, _______________________ Taiwan is the largest.
中國有很多島嶼，臺灣是其中最大的一個。
(4)They arrived at a house, _______________________.
他們到達一所房子，前面坐著一個小男孩。
(5)Gun control is a subject ________ Americans have argued for a long time.
which which
t which which
(6)By nine o’clock, all the Olympic torch bearers had reached the top of Mount Qomolangma, ________ appeared a rare rainbow soon.
which which
which e which
(7)For many cities in the world, there is no room to spread out further, _____ New York is an example.
which which
which which
注意：The way ________ he explained to us was quite simple.
The way ________ he explained the sentence was simple.
難點三：引導詞as , which
1.引導非限制性定語從句，指代整個主句內容時的區別：
(1)表達“正如”之意時，用as, 如果僅指代整個主句內容而沒有“正如”之意，則用which。
He went abroad, ______ was unexpected.
She is a good mother, _____ her mother used to be.
(2)當從句位於主句前面時，用as。
______ is known to everybody, the moon travels round the earth.
2.限制性定語從句中有such, the same 時，其後常用as 引導定語從句。
He is such a good teacher _______ we all love and respect.
This is the same pen _______ I lost.
h既可指代整個主句內容，又可以指代先行詞。
The river, _______ flows through London, is called the Thames.
常與從句中的know, see, hear, expect等動詞連用，也常用於as often happens, as is often the case等句子中。
He was absent from school, _______ is often the case.
難點四關係代詞與關係副詞(補全法或還原法)
you still remember the chicken farm ________ we visited three months ago?
an hour, we can travel to places ________ would have taken our ancestors days to reach.
pre-school children go to a day care centre, ________ they learn simple games and songs.
練習：
16:30, ________ was almost closing time, nearly all the paintings had been sold.
h
2.A woman with a bleeding hand hurried in and asked, “Is there a hospital around ________ I can get some medicine for my wounded hand?”
h
e
3.—How do you like the film Examination 1997, Mr. Li?
—It brings the hours back to me _____ I was forced to raise pigs in a faraway village.
e
難點五先行詞為point, case, situation等時所構成的定語從句
1.—Do you have anything to say for yourself?
—Yes, there’s one point ______ we must insist on.
e
D./
2.I have reached a point in my life ______ I am supposed to make decisions of my own.
h e
new partnership with France Telecom is really a win-win situation _____ both sides benefit a great deal.
h
e
y, we’ll discuss a number of cases _____ beginners of learning English fail to use the language properly.
h
e
’s helpful to put children in a situation ___________________________________.
把孩子們放在一個能使他們從另外一個角度認識自己的環境中對他們有益。
there is just one point _____________________________________.
現在只有一點你能弄清楚。
