The imperfect tense communicates:

• continuing past events (translates English was __ing)
• customary, habitual events in the past
• planned future events

Verbs are conjugated to the imperfect by taking off the last two letters of the infinitive and replacing them with an ending based on -ía or -aba.

Conjugating regular verbs in the imperfect

This is probably the easiest verb tense to conjugate.

-AR verbs take on the -aba andings. Here is an example:

Bailar (to dance)

bailaba: I danced
bailabas: you danced
bailaba: he, she, it, you (formal) danced
bailábamos: we danced
bailaban: they, you (plural, formal) danced

-IR and -ER verbs take on -ía endings. Examples:

Venir (to come)

venía: I came
venías: you came
venía: he, she, it, you came
veníamos: we came
venían: they, you came

Comer (to eat)

comía: I ate
comías: you ate
comía: he, she, it, you ate
comíamos: we ate
comían: they, you ate

Irregular verbs

There are not many.

Ser (to be)

era: I was
eras: you were
era: he, she, it was, you were
éramos: we were
eran: they were

Notice the accent on the "e" in the "nosotros" form.