Final answer:
The imperfect form of the verb in the sentence is correct as written. The sentence 'Rosa vivía en Londres' means 'Rosa used to live in London.'
Step-by-step explanation:
The imperfect form of the verb in the sentence is correct as written. The sentence Rosa vivía en Londres is in the imperfect tense, which is used to describe ongoing or habitual actions in the past. In this case, it means 'Rosa used to live in London.' The imperfect form of the verb 'vivir' (to live) is 'vivía'.
Learn more about Imperfect form verbs in Spanish