Preterite vs Imperfect: Decision Rules for Past Narration and Description

Why Spanish Has Two Main Past Tenses for Storytelling

Spanish commonly uses two simple past tenses to talk about completed time in the past: the pretérito (preterite) and the imperfecto (imperfect). They are not interchangeable “two ways to say the past.” They divide labor: one tense moves the story forward with events, and the other builds the background with descriptions, ongoing situations, and repeated actions.

A useful mental model is foreground vs background. The preterite is the foreground: the sequence of actions that happened and advanced the timeline. The imperfect is the background: what was going on, what used to happen, what things were like, and what was happening when another event occurred.

Decision Rules: A Practical Flow for Choosing Preterite or Imperfect

When you are narrating in the past, you can decide quickly by asking a small set of questions. Use this as a step-by-step checklist.

Step 1: Are you presenting an event as completed and bounded?

If you are treating the action as a completed whole (with a clear endpoint, explicit or implied), choose preterite.

• Preterite: Ayer llegué tarde. (I arrived late yesterday.)
• Preterite: El lunes compramos un coche. (On Monday we bought a car.)

Signals that often push you toward preterite: a specific time marker (ayer, anoche, el lunes, en 2019), a sequence of actions, or a “one-time” framing.

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Step 2: Are you describing a situation in progress, a habit, or background context?

If you are describing what was ongoing, habitual, or setting the scene, choose imperfect.

• Imperfect (ongoing): Estaba cansado. (I was tired.)
• Imperfect (habit): De niño, jugaba en la calle. (As a child, I used to play in the street.)
• Imperfect (scene): Hacía frío y llovía. (It was cold and it was raining.)

Step 3: Are you answering “what happened?” or “what was it like/what was going on?”

This question is surprisingly reliable.

• What happened? → preterite: Sonó el teléfono. (The phone rang.)
• What was going on? → imperfect: Sonaba música. (Music was playing.)
• What was it like? → imperfect: La casa era grande. (The house was big.)

Step 4: Is there an interruption pattern (ongoing action + sudden event)?

A classic narration structure is: imperfect for the ongoing background action + preterite for the interrupting event.

• Yo leía cuando sonó el teléfono. (I was reading when the phone rang.)
• Estudiábamos y de repente se fue la luz. (We were studying and suddenly the power went out.)

In this pattern, the imperfect paints the “in progress” state; the preterite marks the event that cuts in and changes the situation.

Step 5: Are you stating a change of state, start/end, or result?

Changes of state and “boundary” verbs often appear in preterite because they present a transition as completed.

• Me dormí a las once. (I fell asleep at 11.)
• Se enojó conmigo. (He got angry with me.)
• Empezó a llover. (It started to rain.)
• Terminamos el proyecto. (We finished the project.)

Compare with imperfect for the ongoing state:

• Dormía cuando llegaste. (I was asleep/was sleeping when you arrived.)
• Estaba enojado. (He was angry.)

Core Uses of the Preterite (Foreground Actions)

1) Completed events in a sequence

Preterite is the default for a chain of events that move time forward.

Me levanté, me duché, desayuné y salí de casa. (I got up, showered, had breakfast, and left the house.)

Notice how each verb is a discrete completed action. This is the “timeline” of the story.

2) A single event viewed as a whole

Even if the action took time, if you frame it as a complete unit, you use preterite.

• Viví en Lima dos años. (I lived in Lima for two years.)
• Estudié toda la noche. (I studied all night.)

The duration is not the key; the key is whether the speaker treats it as bounded and complete.

3) Specific moments and “one-time” occurrences

• Una vez vi a un actor famoso. (Once I saw a famous actor.)
• El sábado conocimos a sus padres. (On Saturday we met his parents.)

Core Uses of the Imperfect (Background, Habit, Description)

1) Ongoing actions without a stated endpoint

Imperfect is used when you do not focus on the beginning or end, but on the ongoing nature.

• Trabajaba mucho. (I was working a lot / I used to work a lot.)
• La gente caminaba por el parque. (People were walking through the park.)

2) Habitual actions and routines

Imperfect often corresponds to “used to” or “would” (habitual) in English.

• Cuando era niño, íbamos a la playa cada verano. (When I was a child, we used to go to the beach every summer.)
• Los domingos mi abuela hacía paella. (On Sundays my grandmother would make paella.)

3) Descriptions: weather, time, age, physical/emotional states

Imperfect is common for setting the scene: what things were like.

• Eran las ocho y hacía calor. (It was eight o’clock and it was hot.)
• La calle estaba vacía. (The street was empty.)
• Tenía veinte años. (I was twenty years old.)
• Me sentía nervioso. (I felt nervous / I was feeling nervous.)

These are not presented as “events” but as conditions in the background.

Meaning Changes: Same Verb, Different Tense, Different Message

Some verbs change meaning depending on whether you use preterite (a change/completion) or imperfect (a state/ongoing). This is not a separate grammar rule; it is the same foreground/background logic applied to verbs that can be either states or transitions.

Querer

• Imperfect: Quería ayudarte. (I wanted to help you / I was wanting to help you.)
• Preterite: Quise ayudarte. (I tried to help you / I wanted to help you [at that moment, with an implied outcome or attempt].)

Poder

• Imperfect: No podía dormir. (I couldn’t sleep [ongoing difficulty].)
• Preterite: No pude dormir. (I couldn’t sleep [that time; result: I did not manage to sleep].)

Saber / Conocer

• Imperfect: Sabía la respuesta. (I knew the answer [state].)
• Preterite: Supe la respuesta. (I found out the answer / I learned the answer.)
• Imperfect: Conocía a Marta. (I knew Marta / I was acquainted with Marta.)
• Preterite: Conocí a Marta. (I met Marta.)

Tener

• Imperfect: Tenía un coche. (I had a car.)
• Preterite: Tuve un problema. (I had a problem / I ran into a problem.)

Estar

• Imperfect: Estaba en casa. (I was at home [background location].)
• Preterite: Estuve en casa. (I stayed/was at home [for a specific time, bounded].)

Practical Narration Templates You Can Reuse

To build fluent past narration, it helps to reuse high-frequency structures. The goal is not to memorize isolated rules, but to apply a repeatable decision process while speaking or writing.

Template 1: Scene-setting + event sequence

Imperfect for the scene, then preterite for the events.

Era de noche y llovía. Yo caminaba rápido por la calle. De repente, escuché un ruido, miré atrás y vi a un perro. Me asusté, pero luego me reí.

Notice: era, llovía, caminaba = background; escuché, miré, vi, me asusté, me reí = events.

Template 2: Ongoing action interrupted by a completed event

Estaba cocinando cuando llegó mi hermana. Hablábamos de trabajo cuando se rompió el vaso.

Use this whenever you want to express “was doing X when Y happened.”

Template 3: Habit in the past + one exception event

Imperfect for the routine; preterite for the exception that stands out.

Siempre tomábamos café después de comer, pero ayer tomamos té porque no había café.

Template 4: Background description + key discovery

La oficina era pequeña y estaba muy silenciosa. Buscaba el documento y no lo encontraba. Entonces abrí el cajón y lo encontré.

Imperfect describes the setting and the ongoing search; preterite marks the decisive actions and result.

Time Expressions: Helpful, But Not Absolute

Time expressions can guide you, but they do not mechanically force one tense. They influence how you frame the action.

Expressions that often pair with preterite (bounded)

• ayer, anoche, anteayer
• el lunes, el año pasado, en 2010
• una vez, de repente, entonces
• por fin, finalmente

Expressions that often pair with imperfect (habitual/background)

• siempre, a menudo, normalmente
• todos los días, cada verano
• mientras, cuando (meaning “while”)
• de niño, en aquella época

But you can still choose based on meaning. Compare:

• Siempre fui puntual. (I was always punctual [viewed as a complete trait over a finished period, often implying “back then, in that phase.”])
• Siempre era puntual. (I was always punctual [descriptive habit/trait, not framed as a closed period].)

Both can be possible depending on what you mean: a closed chapter of life vs a general background trait.

Common Trouble Spots and How to Decide

“When” clauses: cuando can trigger either tense

Cuando does not automatically mean preterite or imperfect. Decide whether the clause describes background (imperfect) or a completed event (preterite).

• Background time frame: Cuando era estudiante, trabajaba los fines de semana. (When I was a student, I worked weekends.)
• Completed event: Cuando llegué, ya se fueron. (When I arrived, they had already left.)

Duration phrases: “for X time” can be either

Duration does not automatically mean imperfect. If the duration is presented as a completed block, preterite is common.

• Preterite (completed block): Vivimos allí cinco años. (We lived there for five years [and then we left].)
• Imperfect (background/ongoing): Vivíamos allí y no queríamos mudarnos. (We were living there and we didn’t want to move.)

Descriptions that become events

Sometimes a description can be reframed as a change, which pushes you to preterite.

• Imperfect (state): Estaba enfermo. (He was sick.)
• Preterite (change): Estuvo enfermo dos semanas. (He was sick for two weeks [bounded episode].)

Mini-Algorithm: Convert a Present Story into Past with Correct Tense Choices

If you have a story in your head, you can systematically assign tenses.

Step-by-step method

• 1) List the “scene” elements: weather, time, setting, ongoing states, habitual context. Mark these as imperfect candidates.
• 2) List the “events”: actions that happen once, start/end something, cause a change, or move the plot. Mark these as preterite candidates.
• 3) Identify interruptions: choose imperfect for the action in progress and preterite for the interruption.
• 4) Check verbs with meaning shifts (e.g., poder, querer, saber, conocer, tener, estar): decide whether you mean state (imperfect) or result/change (preterite).
• 5) Read your narration and ask: “Does this sentence advance the timeline?” If yes, preterite. If it paints the background, imperfect.

Worked example

Idea: “It was raining. I was driving. I saw an accident. I stopped and called the police. People were shouting.”

Llovía y yo conducía por la autopista. De repente vi un accidente. Paré el coche y llamé a la policía. La gente gritaba y algunos ayudaban a los heridos.

Background: llovía, conducía, gritaba, ayudaban. Events: vi, paré, llamé.

Practice Sets: Choose the Tense Based on the Decision Rules

Use these to test your decision process. Try to justify each choice with one of the rules above (completed event, background description, habit, interruption, change of state).

Set A: Fill in with preterite or imperfect

• 1) Mientras yo ________ (leer), mi amigo ________ (entrar) en la habitación.
• 2) De niño, ________ (tener) miedo a la oscuridad.
• 3) Ayer ________ (tener) una reunión importante.
• 4) La casa ________ (ser) vieja y ________ (estar) en una calle tranquila.
• 5) ________ (llover) cuando ________ (salir) de casa.

Set B: Same verb, different meaning

• 1) No ________ (poder) abrir la puerta durante diez minutos. (ongoing struggle)
• 2) No ________ (poder) abrir la puerta y me fui. (result: didn’t manage)
• 3) ________ (conocer) a su hermano en la fiesta. (meeting event)
• 4) Ya ________ (conocer) a su hermano. (prior acquaintance)

Answer key with brief reasoning

• A1: leía (ongoing) / entró (interrupting event)
• A2: tenía (habitual/background state)
• A3: tuve (one-time event: “had a meeting”)
• A4: era (description) / estaba (location/state description)
• A5: llovía (background) / salí (completed event)
• B1: podía (ongoing inability)
• B2: pude (result: didn’t manage)
• B3: conocí (met)
• B4: conocía (knew)