To form the imperfect, drop the infinitive ending and add -aba, -abas, -aba, -ábamos, -abais, -aban to -ar verbs, or -ía, -ías, -ía, -íamos, -íais, -ían to -er and -ir verbs; only ser, ir and ver are irregular (era, iba, veía). Use it for what you used to do repeatedly, for descriptions and background in the past (age, weather, feelings, scenes), and for an action already in progress when something else happened — the interrupting event goes in the preterite.
Examples
- Cuando era pequeño, vivía en el campo y jugaba en la calle todos los días.
- When I was little, I lived in the countryside and played in the street every day.
- Hacía frío y no había nadie en la plaza.
- It was cold and there was nobody in the square.
- Mientras leía, sonó el teléfono.
- While I was reading, the phone rang.
- Antes íbamos al cine cada domingo, pero ahora vemos películas en casa.
- We used to go to the cinema every Sunday, but now we watch films at home.
The mistake to avoid
Learners often use the preterite for repeated or background past actions (*fui al parque todos los días*), when Spanish requires the imperfect (iba al parque todos los días).
Where this fits in
The imperfect: past habits & descriptions, Spanish B1: Use the imperfecto to talk about how things used to be, describe the past, and narrate ongoing actions interrupted by another event.