We use the imperfect tense in Spanish to talk about an action in the past which is either repeated or habitual. English has several ways of conveying this was/were doing, used to do, would do, did:
Cuando era niño, visitaba a mis abuelos a menudo (When I was a child, I often used to visit/often visited my grandparents).
Nadabas cada semana (You would go/You used to go/You went swimming every week).
Cuando viviamos en España, ibamos a la playa (When we lived in Spain, we used to go/they would go to the beach).
The imperfect is also used:
- To describe an emotional or mental state in the past:
Cristina se sentía triste (Cristina felt sad).
- With mientras (while) to talk about two things that were happening at the same time:
Teresa veía la tele mientras cenaba (Teresa watched television whilst she ate supper).