You have already learned one past tense in Spanish, the preterite, which is used to talk about actions or events that are completed. The imperfect is another past tense in Spanish. It is used to talk about actions or events that were in progress in the past, things that were habitual or customary, or that happened over a long period of time. It is also used to describe ongoing mental, physical, or emotional states in the past, and to tell time in the past.

-ar verbs	-er verbs	-ir verbs
HABLAR	COMER	VIVIR
hablaba	comía	vivía
hablabas	comías	vivías
hablaba	comía	vivía
hablábamos	comíamos	vivíamos
hablabais	comíais	vivíais
hablaban	comían	vivían

Only three verbs are irregular in the imperfect tense.

IR	SER	VER
iba	era	veía
ibas	eras	veías
iba	era	veía
íbamos	éramos	veíamos
ibais	erais	veíais
iban	eran	veían

There are no stem-changes in the imperfect tense. Verbs that are stem-changing in the present or preterite are conjugated like regular verbs in the imperfect: volvía, jugaba, pensaba, perdía, etc.