Question tags are short questions at the end of statements.
Tag questions (or question tags) turn a statement into a question. They are often used for checking information that we think we know is true.
They are mainly used in speech when we want to:
- confirm that something is true or not
- to encourage a reply from the person we are speaking to.
Tag questions are made using an auxiliary verb (for example: be or have) and a subject pronoun (for example: I, you, she). Negative question tags are usually contracted
- It's warm today, isn't it (not 'is it not')
Usually if the main clause is positive, the question tag is negative, and if the main clause is negative, it's positive.
- It's cold (positive), isn't it (negative)?
- It isn't cold (negative), is it (positive)?
If the main clause has an auxiliary verb in it, you use the same verb in the tag question. If there is no auxiliary verb (in the present simple and past simple) use do / does / did (just like when you make a normal question).
- They live in London, don't they?