Answer:
i think i understand it now,
Explanation:
you have to write out what you added to the first part of the verb "est" like what you add to make it change
1. oy
2. as (with an accent on the a)
3. a (accent)
4. amos
5. an (accent on a)
THE RIGHT ANSWER IS:
LOS ALUMNOS NO ESTUDIARON ANOCHE :)
HOPE THIS WAS HELPFUL FROM ALL THE OTHER ANSWERS IM SPANISH BTW