替代是一種避免重復(fù)的連接上下文的手段。在英語中主要有三種替代現(xiàn)象：名詞性替代、動詞性替代和分句性替代；同理，替代詞也分為名詞替代詞、動詞替代詞和分句替代詞。此外還有狀語的替代。
一、名詞性替代
用名詞性替代詞one (s), the same, the kind, the sort等所表示的替代現(xiàn)象叫做名詞性替代。
1.名詞性替代詞
例1：the child doesn’t like this book. show him a more interesting one. (one = book)
例2：his novel is a bad one for children. (one = novel)
2.某些不定代詞
在名詞性替代中還可以用一些不定代詞來替代。如all, both, some, any, enough, several, none, many, much, more, (the ) most, (a) few, another, the other, others, either等。例如：
i don't want any more food. i’ve had enough.
3. one 和 ones是最常見的替代詞
one的復(fù)數(shù)形式是ones.one 和ones作為替代詞只能用以替代可數(shù)名詞， 不可用來替代不可數(shù)名詞。例如：
1）the grey horse is stronger than the black one.
2）the new design is much better than the old ones.
4.名詞性物主代詞mine，yours
名詞性物主代詞mine, yours等可用來代替my +名詞，your +名詞等，例如：
“whose is that coat?” “it’s mine.”
二、動詞性替代
用動詞替代詞do，do so等所表示的替代現(xiàn)象叫做動詞性替代。
1.謂語的替代形式
do是謂語的替代形式，有時態(tài)和人稱的變化。例如：
1）some people like a shower after they have played tennis. peter does, for example.
2）john speaks german as fluently as mary does.
2.由do，so等組成的復(fù)合替代形式
（1）“so +助動詞+主語”。例如：
“mary will enter the university in september.” “so will joan.”
（2）“so +主語+助動詞”。例如：
“i’ve been to beijing.” ”so you have.”
注：這種結(jié)構(gòu)中第二句的主語與第一句的主語是同一個人，否則應(yīng)像“so +助動詞+主語”的結(jié)構(gòu)一樣，主謂要倒裝。
（3）“主語+（助動詞+）do + so”。例如：
“have you sent your plan to the committee?”
“i did so yesterday.”
（4）“主語+（助動詞+）do + that”。例如：
“do you know who broke the television set?”
“i heard john did that.”
（5）“主語+（助動詞+）do + it”。例如：
“my brother said he was going to send a letter of protest to the president.” ”i did it last week.”
注：如果上文表示否定意義而在簡短反應(yīng)中表示相同的看法時，則用“neither / nor +do +主語”。此時，do 不是動詞替代詞，而是助動詞。例如：
mary didn’t like english, neither did her brother.
3.to代替整個動詞不定式
當(dāng)某個動詞不定式詞組在句子中再次出現(xiàn)時，我們可以只用to這個詞，而不必重復(fù)整個動詞不定式詞組。例如：
1）i went there because i wanted to. (=…because i wanted to go there.)
2）perhaps i’ll go to brazil this summer; i’d very much like to.
3）“are you and gillian getting married?” ”we hope to.”
4）i think he should get a job, but you can’t force him to if he’s not ready (to).
5）i don’t dance much now, but i used to a lot.
6）we’ll never leave home; he hasn’t got the courage (to).
注1：有時to可省略（尤其是在形容詞和名詞之后，見例4、6）。在某些動詞（如try）之后也可省略to。例如：
“can you start the car?” “ok, i’ll try.”
注2：在want和would like之后，通常不能省略to。然而，當(dāng)want或like 用于從句時（例如，在when, if, what, as之后），to常常省略。例如：
1）come when you want.
2）i’ve decided to do what i like.
3）come and stay as long as you like.
三、分句性替代
用分句替代詞so或not替代整個分句的現(xiàn)象叫做分句性替代。例如：
many people believe that there will be another world war before the end of the century. my father think so, but i believe not.
1.分句替代詞so或not可替代that從句
so可用來替代肯定的that從句，not替代否定的that從句，它們常與i’m afraid, believe, expect, fear, guess, hope, suppose, think等詞語搭配。例如：
1）“have we got enough money?” “i think so.”
2）“we’re not going to be in time.” “no, i suppose not.”
2. so與not可用來代替if 后面的從句
例1：are you free this evening? if so, come and have a drink with us.
例2：are you busy this afternoon? if not, i wish you would stay with me for a while.
3.用it, this, that, such作為替代詞
例1：if you don’t work hard, you’ll regret it. (regret it = regret not working hard)
例2：he was very tired. this explains why he went to bed early.
例3：you’re trying to cut with the back of the knife; that’s a silly thing to do.
例4：i may hurt your feelings, but such (= that) was certainly not my intention.
四、狀語的替代
1.時間狀語的替代形式主要用副詞then
例如：we saw john at eight on monday evening. we told him then that we could be coming to the party.
2.地點(diǎn)狀語的替代形式主要用副詞here和there
例如：mary is in london and john is there too.
it和that有時也可以用作地點(diǎn)狀語的替代形式，這種場合的it和that在句中作主語，并可同there交換使用，謂語動詞是聯(lián)系動詞。
例如：they sat right in front of the stage. that / it / there was where the noise was greatest.
3.方式狀語的替代形式用in that way和like that
例如：“she plays the piano with great concentration and with great energy.” “i’m afraid she doesn’t study like that.”