Question tags are the small questions that often come at the end of sentences. Question tags are common in speech and informal writing. They are unusual in formal writing.
- It is very hot, isn’t it?
- She can swim, can’t she?
- She sings well, doesn’t she?
In question tags negatives are usually contracted, but full forms are possible in formal speech.
- That’s the postman, isn’t it? (Informal)
- They said they would finish the work in six months, did they not? (Formal)
Question tags are used to check whether something is true, or to ask for agreement.
Negative after affirmative, and vice versa
Question tags are used after affirmative and negative sentences. They are not used after questions.
Compare:
- You are the new Chairman, aren’t you?
- You aren’t the new Chairman, are you?
- (BUT NOT Are you the new Chairman, aren’t you?)
To check information or ask for agreement, we most often put negative tags after affirmative sentences, and non-negative tags after negative sentences.
- It’s cold, isn’t it? (NOT …is it?)
- It isn’t very cold, is it? (NOT …isn’t it?)
Auxiliaries
If the main sentence has an auxiliary verb, this is repeated in the question tag.
- You aren’t busy, are you?
- She can’t swim, can she?
- They didn’t come, did they?
- We shouldn’t wait, should we?
If the main sentence has no auxiliary, the question tag has do.
- You like fish, don’t you?
- He likes fish, doesn’t he?
- She came, didn’t she?