Student or Learner
how should I say?
They had their house painted, hadn't they?
They had their house painted, didn't they?
had is in the past tense , so it would be correct to use didn't in the tag but the answer in my book is hadn't
if the construction were in the negative they didn't have their house painted, did they? that would be the answer so, why does the book give me the "hadn't" tag for the affirmative?
I guess (but disagree) the reasoning is that had should be treated as an auxiliary verb, like be in the passive. That said, I cannot improve on Kfredson's excellent scoring system.