英語的代替現象比漢語普遍，使用代詞的場合比漢語多。大多數句子中均用代詞代替上文談到的人、事物或情況，避免了對較多名詞、冠詞的反復使用，這樣大大簡化了句子。
最常用于表示替代關系的詞語有it, that, which, one, so等，近幾年高考試題中均對這些詞的用法進行了考查，可見這幾個替代詞的用法非常重要。下面歸納它們表示替代時的不同用法。
一、it的用法
1、it指代上文所提事物的本身（it表時間、強調等的用法此處不闡明），如果所代替的事物為復數，則應該用they或them表示。
2、it也可以用來代替上文所提到的一件事。
1.The Parkers bought a new house but _____ will need a lot of work before they can move in. (NMET2001,25)
A.they B.it C.one D.which
2.I am looking for a house. I’d like ____ with a brook around_____.
A.one,it B.it,it C.one,one D.it,one
3.Mary’s mother always told her to work hard, but______didn’t help.
A.one B.he C.she D.it
4. -Do you like these photos? - Yes, ____are very beautiful and I like____ very much.
A.they,those B.they,them C.ones,ones D.the ones, the ones
5.-Are you still using your old car? --No, I sold___the other day.
A.it B.one C.that one D.the one
6.Yesterday I lost my pen, but now I have found_____.
A.it B.them C.ones D.those
7.-Where are my books? --_____ are on the TV set.
A.Ones B.Those C.The ones D.They
8.Where have you put my shoes? I can’t find_____anywhere.
A.them B.those C.ones D.the ones
9.Where did you buy the watch? Would you please get____ for me?
A.it B.one C.the one D.them
10.Don’t read in the sun. ____ is bad for your eyes.
A.One B.The one C.It D.This
二、that的用法
1、that用來指前文中確定的非同一事物，常用來替代與定冠詞或形容詞性物主代詞連用的單數可數名詞或不可數名詞，相當于“the+名詞”，其復數形式為those。
2、that表替代時為始終是特指（作指示代詞和關系代詞用時另論），可指上文談到的人、物或情況（均為單數），可代替可數名詞和不可數名詞。
3、若that所代替的內容為前置用法，即要代替的內容將出現在下文中，一般用this,these或the following表示。
1.-He was nearly drowned once
-When was_______?(NMET2002 Beijing spring)
-_____was in 1998 when he was in middle school.
A.that,It B.this,This C.this,It D.that,This
2.Equipped with modern facilities, today’s libraries differ from______ (2003 Shanghai spring,26)
A.those of the past B.the past C.which of the past D.those past
3.Few pleasure can equal __of a cool drink on a hot day. (NMET99,17; NMET99 Guangdong,29)
A.some B,any C.that D.those
4.The population of Sichuan Province is larger than ____of any province in China.
A.one B.it C.that D.the one
5.What I want to suggest is_____: Everyone should have another try. We needn’t only wait for help.
A.that B.this C.it D.one
6.You see, the accident happened like_____: The red car hit the bus and made all the traffic stop.
A.that B.this C.it D.one
7.Listen! ________ is about the lessons we will have to finish today.
A.It B.The one C.The following D.One
8.The climate here is quite different from____ of Shengyang.
A.that B.it C.one D.the one
9.The study of idioms is as important as____ of grammar.
A.one B.that B.it D.this
10.My seat is next to_____ of my teacher.
A.that B.it C.this D.one
三、which的用法
1、在后置的非限制性定語從句中代替上文出現的事物或情況（單數或復數）。
2、在問句中作為疑問代詞，在名詞從句中作為連接代詞用，其含義為“哪個、哪些”。
3、如果非限制性定語從句的先行詞不是指主句內容，而是指具體的人、時間、地點，則不用which。
4、如果非限制性定語從句前置，則用as。
1.Dorothy was always speaking highly of her role in the play, _____, of course, made the others unhappy. (NMET2000,17)
A.who B.which C.this D.what
2.The result of the experiment was very good, which we hadn’t expected. (NMET2000 Beijing spring,10)
A.when B.that C.which D.what
3.China has its own English language newspaper, China Daily,______is published in Beijing.
A.that B.it C.which D.one
4.China Daily has plenty of advertisements, _____ help to cut the costs of making the newspapers.
A.that B.it C.which D.they
5._____ would you like better, the blue one or the red one?
A.Which B.What C.That D.How
6.I don’t know in_____ direction the thief ran away.
A.whose B.what C.which D.where
7.The old scientist went to the U.S.A in 1921, _____ he spent his last years.
A.which B.when C.where D.that
8.____we all know, China is developing at a great speed to catch up with the western countries.
A.Which B.That C.It D.As
9.At last we came to an old castle, _____ roof was in a bad state.
A.which B.what C.whose D.that
10.The man was standing behind the window, _____ he could see what was happening outside the house.
A.from which B.from where C.where D.which
四、one 的用法
1、 常用來代替與上文所提到人或物相類似的不確定的另一人或物（泛指），且被替代者為可數名詞單
數形式。
2、 若下文替代者表示非特指含義，則用a/an-adj-one形式表示；若下文替代者為另一特指含義，
則用the one或the-adj-one表示；若下文替代時為復數含義，則用the-adj-ones 或the ones表示。
3、 one作替代詞用時，其前可加某些形容詞或限定詞，如the,this,that,which,each,every,any，但一般不
能直接在其前加物主代詞。
4、one被后置定語修飾表示特指時，前面應加the；被形容詞修飾表示泛指時，其前應加a/an；被形容詞修飾表示特指時其前應加the。
5、one作主語時，其對應的物主代詞用 one’s或 his，反身代詞用 oneself或 himself，重復主語用 one 或he。
1.I hope there are enough glasses for each guest to have_______ . (NMET95,21)
A.it B.those C.them D.one
2.-Why don’t we take a little break? -Didn’t we just have________? (NMET2000,23)
A.it B.that C.one D.this
3.Meeting my uncle after all these years was an unforgettable moment, one I will always treasure. (NMET2002,35)
A.that B.one C.it D.what
4. -Did a letter come for me? -Yes, there was _______for you this morning.
A.one B.it C.the one D.that
5.He has a blue pen and two red ______.
A.one B.ones C.those D.the ones
6.I brought a necklace to you that day, but it was________.
A. a different one B.different one C.the different one D.different ones
7.I don’t like this blue cat, I’d like______.
A. the red one B.red one C.a red D.that red
8.I don’t like this expensive cake, _______ is OK.
A.cheap one B.that cheap C.a cheap one D.a cheap
9.____should love____country.
A.One,her B.She,her B.One,one’s D.One,ones
10.Such a drug will make_____ find it hard to go without it.
A.it B.that C.one D.ones
11.Yesterday I lost my pen, but I’ve bought______.
A.it B.that C.one D.the one
12.Young people like seeing the film, but old_____ don’t.
A.those B.ones C.one D.them
13.This book is_____that is needed by all of us.
A.it B.one C.that D.the one
14.He is_____who gave us the talk yesterday.
A.that B.one C.the one D.himself
15.Is this museum_____they paid a visit to yesterday?
A.that B.where C.the one D.which
16.Your old bike is_____, it’s much better than_____
A.a good one,my new one B.good one,my one
C.a good,my new one D.one good,new my one
17.This advice is different from_____.
A.that one B.that C.it D.the one
18.The books on the table are more than____ on the bookshelf.
A.they B.them C.those D.ones
19.A cake made of wheat costs less than____ made of rice.
A.one B.it C.those D.that
20.Do you like red ink or_____?
A.blue one B.blue C.the blue one D.red ink
21.The step you’ve taken is_____ of much risk.
A.one B.that C.it D.ones
22.I’m told you’ve got some foreign stamps. Will you please give me_____?
A.one B.it C.that D.the one
五、so的用法
1、so表示替代常用來代替上文中出現的內容，尤其是上文內容在下文中以賓語從句形式出現時。
2、如果在下文被代替者為否定含義的賓語從句，常用否定動詞+so或直接用not代替。如：
1. -The boys are not doing a good job at all, are they?
-______.(NMET2003 Beijing spring,22)
A.I guess not so B.I don’t guess C.I don’t guess so D.I guess not
2. -Do you think it’s going to rain over the weekend?
-_____.(NMET94,13)
A.I don’t believe B.I don’t believe it C.I believe not so D.I believe not)
3. -Do you think it’s going to rain again? -I _____, but I _____.
A.think not,hope so B.not think,so hope C.don’t think so,don’t hope so D.think not,hope not
4.-Do you think it’s going to be fine ? --Yes, and I______.
A.expect that B.expect so C.expect it D.expect them
5.-Will they come back again? --No, I_____.
A.don’t believe B.not believe C.believe not D.don’t believe that