Imperfect Tense

Formation

There are 2 sets of conjugations for regular verbs in the imperfect tense.

This tense is formed by adding the endings to the stem of the verb.

Here are the endings for regular verbs that end in -ar.

 singularplural
first personabaábamos
second personabasabais
third personabaaban

yohablaba
tú hablabas
él/ella/usted hablaba
nosotros hablábamos
vosotros hablabais
ellos/ellas/ustedes hablaban

Here are the endings for regular verbs that end in -er or -ir.

 singularplural
first personíaíamos
second personíasíais
third personíaían

yo bebía
bebías
él/ella/usted bebía
nosotros bebíamos
vosotros bebíais
ellos/ellas/ustedes bebían

Usage

In general, the imperfect tense in Spanish will correspond with these English equivalents:

yo hablaba = I was speaking, I used to speak

When to use the Imperfect Tense:

The imperfect tense is used for past tense actions where there is not a specified completion. This includes habitual/continuous actions in the past. Also note that the imperfect is used for descriptions in the past. Vivía en México.I used to live in Mexico.
La casa era verde.  The house was green.
There are several common phrases that indicate that the imperfect tense should be used. It is helpful to remember these types of phrases. Here are some common ones:

always
sometimes
often/frequently
every day
every year
siempre
a veces; de vez en cuando
a menudo; frecuentemente
cada día
cada año