The sentences must be filled with this words:
- Nosotros nos levantamos a las seis de la mañana.
- Margarita se cepilla los dientes a las 9:30.
- Los estudiantes se despiertan a las seis menos cuarto.
The hour is always said with "a las" when, in that time, there is a plan or a thing to do. On the other hand, the type of "se" shown is one used for expressing something you (or with other people) do for yourself.