This is the 9383rd most frequent Spanish word.
agregaron
"Agregaron" means "they added."
Here, 'agregaron' is used to indicate the action of adding or including, performed by the students on comments within the context of a report.
Los estudiantes agregaron comentarios útiles al informe.
The students added helpful comments to the report.
In this case, 'agregaron' signifies the action of attaching or including photos to the memory album carried out by my friends.
Mis amigos agregaron fotos al álbum de recuerdos.
My friends added photos to the memory album.
Here, 'agregaron' is used to describe the action of adding or incorporating additional details meant to enhance the project.