Use the same verb in the question tag as in the question: He is...isn't he? She does...doesn't she? Be careful: When the question uses "Will..." the question tag is "won't you" For example: He will come with his dog, won't he? If there is a full verb in the sentence, use don't, doesn't, didn't or do, does, did to form the question tag. For example: He knows you, doesn't he?