Puedes ser mas especifico?
Answer: The difference between the tenses is when you use them. Pluperfect is commonly used in conversation. Preterit perfect is commonly used in formal writing and literature. In most cases, you're going to use the pluperfect.
Explanation: hope this helped :)
The dialogue translates to:
<span>Ignacio: I went on vacation for 20 days
Marta: When did your vacation started?
Ignacio: _______.
Last week
The day before yesterday
Last night
Last month
Therefore the answer is el mes pasado (last month) </span>
