Answer:
The correct conjugation of the verb is:
Nosotros habíamos prevenido
Step-by-step explanation:
The past perfect tense consists in using the following combination:
Pronoun + "Haber" in imperfect past tense + The verb in perfect past tense
The correct conjugation of the verb is:
Nosotros habíamos prevenido
Here is an example just for fun:
Nosotros habíamos prevenido al Señor de Guayas del regreso de la Crustácea.