Final answer:
The imperfect form of the verb 'ir' is 'iba'. It is used to talk about repeated or ongoing actions in the past.
Step-by-step explanation:
The imperfect form of the verb 'ir' in the given sentence is iba.
The verb 'ir' means 'to go' in English and its imperfect form is used to talk about repeated or ongoing actions in the past. In this sentence, it describes Teresa's repeated action of going to parties at Damián's house.
For example: Yo iba a la playa todos los veranos. (I used to go to the beach every summer.)
Learn more about Spanish verb conjugation