1. unattempted mi padre __ todos los días en casa antes de ir a su trabajo. desayunaba desayunó
2. unattempted nosotros __ tan jóvenes cuando nos casamos. fuimos éramos
3. unattempted __ muy cansada cuando salí de mi trabajo, por eso no fui al concierto. estaba estuve
4. unattempted ayer __ un regalo precioso para mi enamorado. compraba compré
5. unattempted mientras yo mi amiga y yo íbamos hablando. conducía conduje
6. unattempted la semana pasada __ muy pesada para mí. era fue

Explanation:

Number 1 is talking about her Father who is no longer here, is the equivalent of "My father used to have breakfast at home before going to work". Number 2 and 6, is a matter of the "ver to be"  meaning, remembar that in Spanish as well as English we interpret it according to the context as "ser o estar" in this statement though is is "ser"-"éramos", in the past. Number 3, "estaba" in the past for an action and "estuve" is the past but to indicate a place. Number 4 again, we are talking in the past, we can see the time expression "ayer" -yesterday; thus, it is compré in the past and not "compraba". Number 5, is the past continuous, when an action in the past takes place at the moment of speaking son this is why is "conducía" and not "conduje" --simple past--.