The auxiliary verbs form their interrogatives simply by inversion. That means we can form a question by putting the auxiliary verb before the subject.
- Susie can knit.
- Can Susie knit?
- She has arrived.
- Has she arrived?
- He will come.
- Will he come?
The auxiliaries can form their negatives by simply adding not.
- She will not come.
- He cannot sing.
- You must not go.
Note that cannot is one word.
The auxiliaries combined with not have contracted forms.
- Will not – won’t
- Cannot – can’t
- Have not – haven’t
- Is not – isn’t
Auxiliaries are the only verbs that can be used in question tags.
- She can sing, can’t she?
- It’s raining, isn’t it?
- He will come, won’t he?
Auxiliaries are the only verbs that can be used in short answers to questions.
- Will he come? No, he won’t. (= No, he won’t come.)
- Can you speak English? No, I can’t. (= No, I cannot speak English.)
Compare this with ordinary verbs.
- Who wrote this letter? I did. (NOT I wrote.)
- Who broke the window? John did. OR John. (NOT John broke.)
Auxiliaries can also be used in short answers to express agreement or disagreement.
- ‘It is very hot.’ ‘Yes, it is.’
- ‘Susie has passed her test.’ ‘Yes, she has.’
- ‘He will help us.’ ‘No, he won’t.’
Auxiliaries are the only verbs that can be used in the constructions given below.
- Julie didn’t turn up, and nor did Susie.
- Julie didn’t turn up, and Susie didn’t either.