Final answer:
The appropriate verb to fill in the blank is 'fuimos,' which is the past tense form of 'ir' (to go) in Spanish.
Step-by-step explanation:
The verb that should be filled in the blank is fuimos, making the sentence 'Hace un mes que fuimos al cine.' The verb 'fuimos' is the past tense form of the verb 'ir,' which means 'to go' in Spanish. It is used when talking about actions that took place in the past.
Learn more about Verb Conjugation in Spanish