Preterite vs imperfect: trigger words, rules and 40 examples
Spanish has two simple past tenses, and English has one, so every learner hits this wall. The fix is not to memorize a list of words; it is to understand what each tense does, then use trigger words as a shortcut. This guide gives you both.
The one idea behind both tenses
The preterite reports an action as a finished whole: it started, it ended, it moved the story along. Ayer comí paella. The imperfect describes what was going on, with no attention to when it started or ended: habits, background, scene-setting, states. De niño, comía paella todos los domingos.
A useful picture: the preterite is a photo of an event; the imperfect is the video playing in the background. When you tell a story, the imperfect paints the scene and the preterite says what happened in it.
Trigger words for the preterite
These expressions pin an action to a specific, finished moment, so the preterite almost always follows.
| Trigger | Meaning | Example |
|---|---|---|
| ayer, anoche, anteayer | yesterday, last night, the day before yesterday | Anoche vi una película. |
| el lunes, el año pasado, la semana pasada | on Monday, last year, last week | El año pasado viajé a Colombia. |
| en 2015, a las tres | in 2015, at three o’clock | En 2015 nació mi hija. |
| de repente, de pronto | suddenly | De repente sonó el teléfono. |
| una vez, dos veces | once, twice | Lo llamé dos veces. |
| hace dos días | two days ago | Hace dos días llegó el paquete. |
| por fin, finalmente | at last, finally | Por fin terminamos el proyecto. |
| entonces, luego, después | then, afterwards | Luego salimos a cenar. |
| durante tres años, todo el día | for three years, all day (a closed period) | Vivió en Madrid durante tres años. |
| desde … hasta | from … until | Trabajó desde las nueve hasta las cinco. |
Trigger words for the imperfect
These expressions describe repetition, routine or an open-ended background, so the imperfect follows.
| Trigger | Meaning | Example |
|---|---|---|
| siempre, nunca (as a habit) | always, never | Siempre llegaba tarde. |
| todos los días, cada verano, los sábados | every day, every summer, on Saturdays | Los sábados íbamos al mercado. |
| a menudo, a veces, muchas veces | often, sometimes, many times | A veces comíamos fuera. |
| generalmente, normalmente, por lo general | usually, normally | Normalmente me levantaba a las siete. |
| de niño, de pequeña, de joven | as a child, when I was little, when young | De niño tenía un perro. |
| mientras | while | Mientras cocinaba, escuchaba música. |
| en aquella época, en esos años | in those days, in those years | En aquella época no había internet. |
| todavía, aún | still | Todavía vivía con mis padres. |
One warning: siempre and nunca go with the preterite when they sum up a finished period: Siempre fue muy generoso (he was generous his whole life, now over). Trigger words are a shortcut, not a law. When they conflict with the meaning, the meaning wins.
The four rules you actually need
1. Completed action → preterite. If you could put a checkmark next to it, it is preterite. Compré el billete. Llegaron a las diez. Se rompió el vaso.
2. Habit or repeated action → imperfect. If the English could be “used to” or “would (every day)”, it is imperfect. Cada verano íbamos a la playa. Mi abuelo fumaba en pipa.
3. Background, description, state → imperfect. Time, age, weather, physical description, emotions and ongoing situations all set the scene. Eran las ocho. Tenía diez años. Hacía frío. Estaba cansada. La casa era grande.
4. Interruption → imperfect for the background, preterite for the interruption. Dormía cuando sonó el teléfono. The sleeping was in progress (imperfect); the phone ringing is the event (preterite). This is the most tested pattern in every Spanish course.
Both tenses in one sentence
Real Spanish mixes them constantly. Watch what each verb is doing:
- Mientras estudiaba, mi hermano entró en la habitación. Background, then event.
- Eran las diez cuando llegamos. Time (scene), then the arrival (event).
- No fui a la fiesta porque estaba enfermo. Finished decision, ongoing state.
- Quería llamarte, pero no tenía tu número. Two states, both imperfect: nothing “happened”.
- Cuando era niño, vivíamos en Lima. Un día mi padre decidió mudarse. Scene, scene, then the event that changed it.
Verbs that change meaning
A few verbs describe a state in the imperfect but an event in the preterite. English often needs a different verb to translate them.
| Verb | Imperfect | Preterite |
|---|---|---|
| saber | sabía = knew | supe = found out |
| conocer | conocía = knew (a person, place) | conocí = met (for the first time) |
| querer | quería = wanted | quise = tried to; no quise = refused |
| poder | podía = was able to (in general) | pude = managed to; no pude = failed to |
| tener | tenía = had | tuve = got, received |
| haber | había = there was (scene) | hubo = there was (an event: an accident, a party) |
Sabía que vivías aquí (I knew you lived here) versus Supe que vivías aquí (I found out you lived here). No quería ir (I didn’t want to go) versus No quise ir (I refused to go).
A story that uses both
Era una noche de invierno y llovía mucho. Yo estaba en casa, leía una novela y tomaba un té. De repente alguien llamó a la puerta. Me levanté, abrí y vi a mi vecina, que tenía cara de susto. Me dijo que se había quedado sin luz. La invité a pasar y pasamos la noche charlando.
Scene-setting verbs (era, llovía, estaba, leía, tomaba, tenía) are imperfect. Everything that moves the story (llamó, me levanté, abrí, vi, dijo, invité, pasamos) is preterite. Read the paragraph again and notice that you could draw a timeline from the preterite verbs alone.
Common mistakes
- Using the imperfect for every long action. Length does not matter; completion does. Vivió en París diez años is preterite because the period is closed.
- Using the preterite for age, time and weather. Tenía veinte años, eran las dos, hacía sol. These describe, so they take the imperfect, unless you mean the moment something changed: cumplió veinte años.
- Translating “was + -ing” as the preterite. “I was reading when…” is leía (or estaba leyendo), never leí.
- Forgetting that había is the normal “there was”. Había mucha gente describes; hubo un accidente reports an event.
How to make it automatic
Knowing these rules is step one. Choosing in under a second is step two, and that comes only from repetition. Our free preterite vs imperfect drill gives you 60 seconds of real sentences with the rule for every miss, and the printable worksheet has 20 more with an answer key. For the irregular forms themselves (fui, tuve, hice, dije), see the irregular preterite drill.
Quick answers
What are the trigger words for the preterite?
Expressions that fix an action at a finished point or closed period: ayer, anoche, el año pasado, la semana pasada, en 2015, a las tres, de repente, una vez, dos veces, hace dos días, por fin, luego, durante tres años, desde … hasta.
What are the trigger words for the imperfect?
Expressions of habit, routine or background: siempre, todos los días, cada verano, los sábados, a menudo, a veces, generalmente, normalmente, de niño, mientras, en aquella época, todavía.
Is “siempre” preterite or imperfect?
Usually imperfect, because it describes a habit: siempre llegaba tarde. But when siempre sums up a finished period as a whole, it takes the preterite: siempre fue generoso (he was generous all his life).
What is the difference between sabía and supe?
Sabía is the imperfect and means “knew” as an ongoing state. Supe is the preterite and means “found out”, the moment the knowing began. Conocía means knew a person; conocí means met them.
When do you use the imperfect for time and age?
Almost always. Telling the time in the past (eran las cinco), stating age (tenía ocho años) and describing weather (hacía calor) set the scene, so they take the imperfect.
Can you use the preterite and the imperfect in the same sentence?
Yes, and it is very common. The imperfect gives the background and the preterite gives the event that happens in it: Dormía cuando sonó el teléfono. Mientras cenábamos, llegó mi hermano.