The preterite is used to narrate completed actions in the past. Certain words like ayer (‘yesterday’), anoche (‘last night’), el año pasado (‘last year’), and la semana pasada (‘last week’), are associated with the preterite, since they usually refer to specific events that are now completed.

The imperfect is used to narrate actions that were habitual or ongoing in the past. There is no reference to whether or not these things were ever completed, or whether they continue into the present time. Phrases like siempre (‘always’), frecuentemente (‘frequently’), and todos los días (‘daily’), are often associated with the imperfect. The difference between the preterite and imperfect is often very subtle, and even native speakers will occasionally disagree about which form is correct. You should study examples and try to imitate native speakers when possible.

Examples of Preterite/Imperfect

• ¿Encontraste el vestido que buscabas?
• No. Había uno negro que me gustaba mucho pero la talla era demasiado grande para mí.
• ¿No tenían tallas más pequeñas?
• Sí. Encontré unos zapatos de cuero a muy buen precio. También compré un traje nuevo.
• Encontré una blusa muy linda que hace juego con mi falda gris. ¿Y tú, compraste los zapatos?