Ellipsis and substitution

Ellipsis

Repeated subject or subject + auxiliary verb

After and, but, and or we can leave out a repeated subject or a subject + auxiliary verb.

• He closed the door and he took off his shoes. 
• We could go out or we could have a party at home.
• She called but she didn’t leave a message. 

Repeated verb phrase or adjective after the same auxiliary

We can avoid repeating an adjective, a verb or a verb phrase and repeat only the auxiliary or modal verb.

• Maria should take the exam, but I don’t think you should take the exam.
• She’ll go to the meeting but I won’t go to the meeting. 
• They say he is the best right now, but I don’t think he is the best.

Use do/does/did in the second clause or sentence when the verb is present or past simple.

• She doesn’t like it, but I do.
• She liked it, but I didn’t.  

Repeated verb phrase after a different auxiliary

We can also omit a repeated verb phrase when we use a different auxiliary or modal verb.

• I’m studying for the exams, but not as much as I should be studying.  
• I told you I’d help you, but I can’t help you.

In the second clause or sentence, we may need to leave two auxiliaries to express past meaning.

• She didn’t win, but she could have won. 
• ‘Did you go?’ ‘No, but I should have gone.’ 

Repeated verb phrase after the infinitive with to (reduced infinitive)

A reduced infinitive is when you leave out a repeated verb phrase after an infinitive with to.

• I shouldn’t go out tonight, but I really want to go out. 
• ‘Are you going to sell the car?’ ‘No, I‘ve decided not to sell the car. ‘

 

Substitution

One, ones

We can use one to avoid repeating a singular countable noun, and we can use ones to avoid repeating a plural noun.

• ‘Do you need a pen?’ ‘No, I’ve already got one.’
• ‘Which car do you prefer?’ ‘I like the red one.’
• Are you going to wear these trousers or the ones that I gave you?
• I’d lend you a pen, but this is the only one I have.

Do so

We can use do so (or does so, did so, doing so, etc.) to avoid repeating a verb phrase.

• If I can help, I’ll be happy to do so. (=to help)
• I won’t apologise, because doing so would be admitting that I was wrong. (=apologising)

We can also use do it/that (more informal) instead of do so.

• They told me to be quiet and I did it/that/so.

If so, if not

We can use if so/if that is so (positive) or if not (negative) to avoid repeating a clause in a conditional sentence.

• Do you want to be better at what you do? If so, pay attention to what I have to say. (=If you want to be better at what you do)
• Mr Chen should be there when you arrive. If not, just give me a call. (=If Mr Chen isn’t there when you arrive)

Using so and not as substitutes for clauses

We use so after certain verbs of thinking and speaking to avoid repeating a positive clause. This use is common with the verbs assume, believe, expect, guess, hope, imagine, presume, suppose, suspect, say, tell sb, think and the expressions be afraid and it seems/appears.

• ‘Are they coming?’ ‘I think so.’ (=they are coming)
• ‘I didn’t do it.’ ‘If you say so.’ (=that you didn’t do it)
• ‘Is she going to be there?’ ‘I hope so.’ (=she’s going to be there)

When we want to avoid repeating a negative clause, we can use a positive verb + not or a negative verb + so.  We can use either of those forms with the verbs appear, seem, suppose.

• ‘Did they leave a copy of the key?’ ‘It doesn’t seem so/It seems not.’

We normally use a positive verb + not with be afraid, assume, guess, hope, presume, suspect.

• ‘Shall we go for a run tomorrow?’ ‘I’m afraid not. I have to be at the office all day.’

We normally use a negative verb + so with believe, expect, imagine, think.

• ‘Will it take long to fix it?’ ‘I don’t think so.’

So, neither

We can use so and neither + auxiliary + subject to avoid repeating a clause when we are agreeing with someone.

• ‘I can be there at any time tomorrow.’ ‘So can I.’ (=I can be there at any time tomorrow too.)
• ‘I shouldn’t take the offer, and neither should you.’ (=and you shouldn’t take the offer either.)

If there is no auxiliary verb in the first clause or sentence, we use do/does or did.

• ‘I love this book.’ ‘So do I.’
• ‘We arrived on time, and so did all the other guests.’