替代是一种避免重复的连接上下文的手段。在英语中主要有三种替代现象：名词性替代、动词性替代和分句性替代；同理，替代词也分为名词替代词、动词替代词和分句替代词。此外还有状语的替代。
一、名词性替代
用名词性替代词one (s), the same, the kind, the sort等所表示的替代现象叫做名词性替代。
1．名词性替代词
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．某些不定代词
在名词性替代中还可以用一些不定代词来替代。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是最常见的替代词
one的复数形式是ones.one 和ones作为替代词只能用以替代可数名词， 不可用来替代不可数名词。例如：
1）The grey horse is stronger than the black one.
2）The new design is much better than the old ones.
4．名词性物主代词mine，yours
名词性物主代词mine, yours等可用来代替my +名词，your +名词等，例如：
“Whose is that coat?” “It’s mine.”
二、动词性替代
用动词替代词do，do so等所表示的替代现象叫做动词性替代。
1．谓语的替代形式
do是谓语的替代形式，有时态和人称的变化。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等组成的复合替代形式
（1）“so +助动词+主语”。例如：
“Mary will enter the university in September.” “So will Joan.”
（2）“so +主语+助动词”。例如：
“I’ve been to Beijing.” ”So you have.”
注：这种结构中第二句的主语与第一句的主语是同一个人，否则应像“so +助动词+主语”的结构一样，主谓要倒装。
（3）“主语+（助动词+）do + so”。例如：
“Have you sent your plan to the committee?”
“I did so yesterday.”
（4）“主语+（助动词+）do + that”。例如：
“Do you know who broke the television set?”
“I heard John did that.”
（5）“主语+（助动词+）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义而在简短反应中表示相同的看法时，则用“neither / nor +do +主语”。此时，do 不是动词替代词，而是助动词。例如：
Mary didn’t like English, neither did her brother.
3.to代替整个动词不定式
当某个动词不定式词组在句子中再次出现时，我们可以只用to这个词，而不必重复整个动词不定式词组。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：有时to可省略（尤其是在形容词和名词之后，见例4、6）。在某些动词（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，当want或like 用于从句时（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
用分句替代词so或not替代整个分句的现象叫做分句性替代。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．分句替代词so或not可替代that从句
so可用来替代肯定的that从句，not替代否定的that从句，它们常与I’m afraid, believe, expect, fear, guess, hope, suppose, think等词语搭配。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与not可用来代替if 后面的从句
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作为替代词
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、状语的替代
1．时间状语的替代形式主要用副词then
例如：We saw John at eight on Monday evening. We told him then that we could be coming to the party.
2．地点状语的替代形式主要用副词here和there
例如：Mary is in London and John is there too.
It和that有时也可以用作地点状语的替代形式，这种场合的it和that在句中作主语，并可同there交换使用，谓语动词是联系动词。
例如：They sat right in front of the stage. That / it / There was where the noise was greatest.
3．方式状语的替代形式用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.”
