Tag questions are short fragments at the end of a sentence. They turn a statement into a question. They are common in spoken English.
Note these uses and examples. The tag is underlined:
⇒ To check if something is true: You’re going to the party tonight, aren’t you?
⇒ To ask for agreement: We should bring a bottle of wine to the party, shouldn’t we?
⇒ To emphasize something: Sara’s certainly self-confident, isn’t she?
⇒ To make a request more friendly: Open the door, could you?
If the verb in the main part of the sentence is positive (+), the verb in the tag is negative (-).
If the verb in the main part of the sentence is negative (-), the verb in the main part of the tag is positive (+).