Final answer:
The appropriate imperfect form of the verb ir in the given sentence is ibas.
Step-by-step explanation:
The correct answer to fill in the blank is ibas. The verb ir means 'to go' in Spanish and in the context of the sentence, the imperfect form 'ibas' is used to indicate a habitual action in the past. The sentence is asking 'Did you go to church every Sunday?'. Here, the imperfect tense is used because it refers to a repeated action in the past.
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