[islam_forever]

To make questions, we use the normal auxiliary did. Note that used to cannot be used in question tag form. Note also the possible/probable replies to used to questions.
Study the following examples:

• 'Did you use to go ice-skating when you were young?'

'No, I never did.'

• 'Didn't you use to ring the school to say you were ill and then go to the cinema?'

'I sometimes did, yeah!'

• 'You used to play truant when you were a school boy, didn't you?'

'Yes, I did.