The answer is "an infinitive verb".
Acabar de + infinitive is used to express an action that has ended prior the enunciation of the sentence.
Answer:
1. Delia vive en los estados Unido
2. Karen y yo comemos pizza
3. Ana corre todos los dias
4. Ellas bebe mucha leche
5. Tu leyes un libro
6. Nostros comimos frutas
Explanation:
I know spanish
The direct object pronoun would be "la" because la gasolina is feminine. In a sentence you could say
La compro en la estacion de servicio.
Direct object pronouns are placed before the verb generally.
Where is the audio, I cannot give you an answer without the audio or link