We use question-tags to make statements and seek agreement from the listener. We form tag question from simple declarative sentences.
We lost the game, didn't we?
John went to school, didn't he?
Jack and Jill didn't go up the hill, did they?
He is a giant, isn't he?
She can't swim, can she?
We form tag questions from negative sentences by copying the auxiliary verb used in the sentence to the sentence end in the positive form. Next we use the pronoun form of the subject of the sentence at the very end of the sentence.
Johncan't play tennis, canhe?
Marywon't go with us, willshe?
Jack and Jillaren't climbing hills anymore, arethey?
Janedid not eat her vegetables, didshe?
You and Iaren't going on a date, arewe?
We form tag questions from positive sentences by copying the auxiliary verb used in the sentence to the sentence end in the negative form. Next we use the pronoun form of the subject of the sentence at the very end of the sentence.
Weare going to win, aren'twe?
Johncan dance very well, can'the?
Marywill be here, won'tshe?
Sentences without Auxiliary Verbs
If there is no auxiliary verb, we use the appropriate tense form of DO in the negative form.
Jack and Jill brought us some water, didn'tthey?
Jane likes vegetables, doesn'tshe?
To Contract or not To Contract
Optionally, we can choose not to contract the auxiliary verb with NOT. The order of the words in a non-contracted tag is 1st the auxiliary verb followed by the subject pronoun and finally NOT.
We are going to win, arewenot?
John can dance very well, canhenot?
Jack and Jill brought us some water, didtheynot?
Jane likes vegetables, doesshenot?
Mary will be here, willshenot?
Non-contracted tags are a little unusual in American English. While the non-contracted tags are grammatically correct, generally in everyday conversation we do contract the auxiliary verb with NOT in the tag question. When we do not contract the auxiliary verb with NOT in a tag question in normal conversation, it comes across as unusually formal and a bit odd.