Questions tags are the same as in Spanish "¿no?":
- you want coffee, don't you? =quieres café ¿no?
- You have seen the film, haven´t you? =has visto la película ¿verdad?
- She's Irish, isn't she? =es irlandesa, ¿a que sí?
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These questions can only be built with special verbs (auxiliary and modal), so if the verb in the main clause is normal, we use always DO. Auxiliary is used in the same time as the main verb of the sentence:
- You like coffee, don´t you?
- You can help me, can´t you?
- He is Mr Smith, isn´t he ?
- They’re making tea, aren’t they?
- Your father will be there by ten, won’t he?
- You’ve been to London, haven’t you?
- Susan bought a new house,  didn’t she?
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Usually you can use "question tag" affirmative  after one negation:
- It isn´t  very cold, is it?
- Mark can't speak French, can he?
- Your cousins didn´t come to visit us, did  they?
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And one  "question tag" negative after one affirmation:
- It is very cold, isn´t it?
- She likes this film, doesn´t she?
- Your friend is going to tell me, isn’t he?