Guide to English grammar

These are cotton. (= These jackets are ...)

2 But we sometimes repeat things for emphasis.

There's this rather nice rose pink, or two or three nice blues, burgundy, and here is one that's a very nice color.
These are cotton, the best cotton one can get.
The assistant wants to emphasize that the colors are all nice and that the material is cotton.
Repeating words in conversation can sometimes make things easier to express and to understand. • 53(1a)

3 Sometimes the words that are left out or replaced come later, not earlier.

If you want to, you can pay by credit card. (= If you want to pay by credit card,...)
After she had had a cup of tea, Phyllis felt much better. (= After Phyllis had had...)
Here she refers forward to Phyllis, which comes later in the sentence.

38 Leaving out words after the auxiliary

1 A sentence can end with an auxiliary if the meaning is clear from the context.
I'm getting old. -Yes, I'm afraid you are.
Kate hadn't brought an umbrella. She was pleased to see that Sue had.
I don't want to answer this letter, but perhaps I should.
Can you get satellite TV? We can.
If the verb is in a simple tense, we use a form of do.
I don't enjoy parties as much as my wife does.
We can also end a sentence with the ordinary verb be.
It's a nice color. At least, I think it is.
The stress can be on the auxiliary or the subject, whichever is the new information.
Yes, I'm afraid you 'are. (emphasis on the fact)
She was pleased to see that 'Sue had. (emphasis on the person)

NOTE
The auxiliary cannot be a short form or weak form.

NOT She was pleased to see that Sue'd.

2 Usually everything after the auxiliary is left out.

I'm getting old. -Yes, I'm afraid you are.
After “are” we leave out getting old. But there are some exceptions to this.

1. 
   We do not leave out not/n't.
   

What did you have for breakfast? ~ I didn't. I'm not eating today.

2. 
   Sometimes we have to use two auxiliary verbs. When the first is a new word, we cannot leave out the second.
   

Have the team won? -Well, everyone's smiling, so they must have.
I don't know if Tom is still waiting. He might be.
When will the room be cleaned? -It just has been.
Here must, might and has are not in the previous sentence.
But when the two auxiliaries are both in the previous sentence, then we can leave out the second.
The corridor hasn't been cleaned, but the room has (been).
You could have hurt yourself. -Yes, I could (have).

3. 
   In British English do is sometimes used after an auxiliary.
   

I don't want to answer this letter, but perhaps I should do. (do = answer the letter)
Have the team won? -Well, everyone's smiling, so they must have done. (done = won)

4. 
   There can be an adverbial or a tag.
   

It's a nice color though. -Yes, it is, isn't it?
Is there a market today? -I don't know. There was yesterday.
Here a market is left out of the answer, but yesterday's new information.

3 A short question consists of an “auxiliary + subject”.

I've seen the film before. Have you? -No, I haven't.
I wanted Helen to pass her test. -And did she? (= And did she pass her test?) -Yes.

A practical guide to English grammar 39