The big question
This is one of the trickiest topics for English speakers. Both the preterite and imperfect translate as "past tense" in English, but they serve different functions in Spanish. Choosing the wrong one won't prevent understanding, but it will sound unnatural - and getting it right is what separates a beginner from an intermediate speaker.
The core distinction
| Preterite | Imperfect |
|---|---|
| Completed action | Ongoing / habitual action |
| Specific time or number of times | No defined endpoint |
| What happened (the event) | What was happening (the background) |
| Advances the story | Sets the scene |
Think of it like a film: the imperfect is the scenery, the weather, what people looked like. The preterite is the action - what happened next.
Side by side examples
| Preterite | Imperfect |
|---|---|
| Ayer comí paella. Yesterday I ate paella. |
De niño comía paella todos los domingos. As a child I used to eat paella every Sunday. |
| Llegó a las tres. He arrived at three. |
Siempre llegaba tarde. He always used to arrive late. |
| Estuve enfermo tres días. I was ill for three days. (then I recovered) |
Estaba enfermo. I was ill. (background state, no endpoint stated) |
| Conocí a María en 2018. I met Maria in 2018. (first time) |
Conocía bien la ciudad. I knew the city well. (ongoing familiarity) |
Using them together - storytelling
In natural speech, the two tenses constantly alternate. The imperfect sets the scene and the preterite moves the story forward:
Era un día de verano. Hacía mucho calor y el sol brillaba. Yo caminaba por la calle cuando de repente vi a un viejo amigo. Estaba sentado en una terraza y bebía un café. Me acerqué y le dije "hola". Hablamos durante una hora. Me contó que vivía en París y que trabajaba como fotógrafo.
It was a summer day. It was very hot and the sun was shining. I was walking down the street when suddenly I saw an old friend. He was sitting on a terrace and was drinking a coffee. I went over and said "hello". We talked for an hour. He told me that he was living in Paris and was working as a photographer.
Analysis
- Imperfect (scene): era, hacía, brillaba, caminaba, estaba, bebía, vivía, trabajaba
- Preterite (events): vi, acerqué, dije, hablamos, contó
The "cuando" pattern
A very common structure: imperfect + cuando + preterite. "I was doing X when Y happened."
- Dormía cuando sonó el teléfono. - I was sleeping when the phone rang.
- Cocinaba cuando llegaron los invitados. - I was cooking when the guests arrived.
- Leía un libro cuando se fue la luz. - I was reading a book when the power went out.
The "mientras" pattern
Mientras (while) usually takes two imperfects - two simultaneous ongoing actions:
- Mientras yo estudiaba, mi hermano veía la televisión. - While I was studying, my brother was watching TV.
- Mientras ella hablaba, él escuchaba con atención. - While she was talking, he was listening carefully.
Verbs that change meaning
Some verbs have slightly different meanings in the preterite vs. the imperfect:
| Verb | Preterite | Imperfect |
|---|---|---|
| saber | supe - I found out | sabía - I knew |
| conocer | conocí - I met (for the first time) | conocía - I knew (was familiar with) |
| poder | pude - I managed to | podía - I was able to (could) |
| querer | quise - I tried to | quería - I wanted |
| no querer | no quise - I refused | no quería - I didn't want to |
| tener | tuve - I received / got | tenía - I had (possessed) |
- Supe la noticia ayer. - I found out the news yesterday.
- Ya sabía la verdad. - I already knew the truth.
- Conocí a tu padre en una fiesta. - I met your father at a party.
- Conocía bien la zona. - I knew the area well.
Dialogue: what happened at the party?
Lucía: ¿Qué tal la fiesta de anoche?
Pablo: Fue genial. Había mucha gente y la música estaba muy buena.
Lucía: ¿Conociste a alguien interesante?
Pablo: Sí, conocí a una chica que se llamaba Sofía. Era colombiana y estudiaba medicina.
Lucía: ¿Y qué pasó?
Pablo: Pues, hablamos un buen rato. Estábamos en el jardín porque dentro hacía mucho calor. De repente empezó a llover y entramos corriendo.
Lucía: ¡Qué divertido! ¿A qué hora te fuiste?
Pablo: Me fui a las dos. Quería quedarme más, pero tenía que trabajar hoy.
Translation
Lucia: How was last night's party?
Pablo: It was great. There were lots of people and the music was really good.
Lucia: Did you meet anyone interesting?
Pablo: Yes, I met a girl called Sofia. She was Colombian and was studying medicine.
Lucia: And what happened?
Pablo: Well, we talked for a good while. We were in the garden because it was really hot inside. Suddenly it started raining and we ran inside.
Lucia: How fun! What time did you leave?
Pablo: I left at two. I wanted to stay longer, but I had to work today.
Practice
Choose preterite or imperfect for each verb:
- Cuando (ser) _____ niño, (vivir) _____ en Sevilla.
- Ayer (llover) _____ todo el día. (single completed period)
- (Caminar - yo) _____ por la calle cuando (ver) _____ el accidente.
- De joven, ella siempre (leer) _____ antes de dormir.
- Anoche (conocí - yo) _____ al novio de mi hermana.
- Mientras nosotros (cenar) _____, (llamar) _____ mi madre.
Answers
- era (imperfect - age/state), vivía (imperfect - ongoing state)
- llovió (preterite - completed action with defined period)
- Caminaba (imperfect - ongoing), vi (preterite - sudden event)
- leía (imperfect - habitual action)
- conocí (preterite - met for the first time)
- cenábamos (imperfect - ongoing), llamó (preterite - interrupting event)
Key takeaways
- Preterite = completed events that advance the story. Imperfect = background, scene-setting, habits.
- The "cuando" pattern: imperfect (ongoing) + cuando + preterite (interruption).
- The "mientras" pattern: usually imperfect + imperfect (two simultaneous actions).
- Some verbs change meaning: saber (knew vs. found out), conocer (knew vs. met), poder (could vs. managed).
- When in doubt, ask: "Am I describing the scene or telling what happened next?"