Explanation: The translation of the sentence is something like:
i ____ shared with my sister.
The options are:
En dos dias más (In two more days)
Mañana por la mañana (Early tomorrow)
A menudo (Usually)
El próximo mes (Next month)
The option that makes most sense is A menudo (usually), because "compartíamos" is in perfect tense (in a past conjugation) and all the other options are in a future.
