Final answer:
The correct verb to fill in the blank is 'vivia'. The sentence is in the past tense, so we use the imperfect tense in Spanish.
Step-by-step explanation:
The correct verb to fill in the blank is vivia.
The sentence translated to English is: 'It's been five years since I lived in the United States.'
This sentence is in the past tense, so we use the imperfect tense in Spanish, which is vivia.
Learn more about Spanish verb conjugation