After habitual past, the imperfect's second-largest job is describing an action in progress at a specific past moment — exactly what English expresses with the past progressive ("I was reading," "they were eating," "she was studying"). The Spanish solution is usually a bare imperfect: leía, comían, estudiaba. The progressive form estaba leyendo also exists, but it's narrower than English speakers tend to assume, and overusing it is a giveaway of a learner translating literally from English.
This page is about teaching you when the simple imperfect is enough — which is most of the time — and when the periphrastic estar + gerundio genuinely adds something.
The basic pattern: simple imperfect for "was doing"
In a sentence with two past actions where one was ongoing and the other interrupted it, peninsular Spanish overwhelmingly uses simple imperfect for the ongoing action and preterite for the punctual one. The structure is so frequent that it's worth memorising as a template:
[Imperfecto] cuando [Pretérito].
Estudiaba en mi habitación cuando llamó mi madre.
I was studying in my room when my mother called.
Cenábamos tranquilamente cuando se fue la luz.
We were having dinner quietly when the power went out.
Veía la tele cuando sonó el timbre.
I was watching TV when the doorbell rang.
Mis hijos jugaban en el parque cuando empezó a llover.
My kids were playing in the park when it started to rain.
Notice: none of those needs estaba estudiando, estaba viendo, estaban jugando. The bare imperfect estudiaba, veía, jugaban already carries the "was doing" meaning. Peninsular Spanish defaults to the simple form here, and using the progressive estaba + gerundio in each of these would sound slightly heavy or emphatic — like an English speaker insisting "I was right in the middle of studying when…".
The mirror clause: imperfect on both sides
When both actions were ongoing in parallel, both verbs go in the imperfect. This is the mientras ("while") pattern:
Mientras yo cocinaba, mi pareja ponía la mesa.
While I was cooking, my partner was setting the table.
Yo leía y los niños hacían los deberes.
I was reading and the kids were doing their homework.
Mientras esperábamos el tren, hablábamos del fin de semana.
While we were waiting for the train, we were talking about the weekend.
Two ongoing actions, no punctual interruption — both verbs stay imperfect. The English version uses past progressive on both sides ("was -ing… was -ing"), and this is one of the few cases where the surface structure matches Spanish neatly.
When estar + gerundio is the better choice
The progressive periphrasis estaba + gerundio (e.g., estaba leyendo, estaba cocinando) is not wrong — it's a real Spanish construction used in real situations. But it's narrower than its English cousin. Use estar + gerundio when:
1. You want to emphasise that the action was actively in progress, not paused or interrupted.
No me hablaste durante la cena porque estabas leyendo el móvil todo el rato.
You didn't talk to me during dinner because you were on your phone the whole time. (emphatic — actively engaged in it)
The simple leías would also work, but estabas leyendo underscores the continuous, active engagement.
2. You want to contrast with the start or end of the action.
Cuando entré, estaba lloviendo, pero diez minutos después había parado.
When I came in, it was raining, but ten minutes later it had stopped.
3. You're describing what someone was doing at a snapshot moment — like a photograph.
Cuando los encontró la policía, los niños estaban jugando al fútbol en el callejón.
When the police found them, the kids were playing football in the alley.
The simple jugaban would communicate the same essential meaning. But estaban jugando paints a snapshot — picture them with the ball, mid-kick. The periphrasis brings the camera in close.
When the simple imperfect is the natural choice
In most narrative contexts, the simple imperfect is the right call. Spanish speakers reserve the progressive for the cases above; everywhere else, the bare imperfect carries the ongoing reading. Consider this short narration:
Aquella tarde llovía, yo escribía un correo y mi gato dormía en el sofá. De repente, sonó el timbre.
That afternoon it was raining, I was writing an email and my cat was sleeping on the sofa. Suddenly, the doorbell rang.
Three ongoing actions (llovía, escribía, dormía) set the scene, all in simple imperfect. The interruption (sonó) arrives in the preterite. A learner translating directly from English might write estaba lloviendo, estaba escribiendo, estaba durmiendo — and the sentence would sound stilted, like an over-careful translation. The native rhythm is the simple imperfect chain.
This is one of the deepest stylistic differences between English and Spanish narration. English drives the past-progressive harder; Spanish leaves more of the "in progress" work to the imperfect itself.
States, perceptions, and mental verbs almost always stay simple
A specific class of verbs almost never appears in the estar + gerundio form when the action is ongoing in the past: stative verbs (knowing, believing, having, loving) and verbs of perception (seeing, hearing). Spanish speakers say:
Sabía que algo iba a pasar.
I knew something was going to happen. (NOT *estaba sabiendo)
Veía las luces de la ciudad desde la ventana.
I could see the lights of the city from the window. (NOT *estaba viendo, in this stative reading)
No te oía con tanto ruido.
I couldn't hear you with so much noise. (NOT *estaba oyendo)
Pensaba que estabas en casa.
I thought you were at home. (NOT *estaba pensando que…)
This restriction also holds in the present (you say sé, not estoy sabiendo), and the imperfect inherits it. The progressive in Spanish is reserved for dynamic actions — things you actively do — and stative verbs simply don't accept it.
What's NOT allowed: *estaba + infinitive
A very common English-speaker error is to combine estar in the imperfect with a bare infinitive instead of a gerundio:
*Estaba estudiar cuando llamó. (wrong)
The Spanish progressive must take the gerundio form (verb stem + -ando for -ar verbs, -iendo for -er/-ir verbs):
- estudiar → estudiando
- comer → comiendo
- vivir → viviendo
- leer → leyendo (with the y spelling rule)
- dormir → durmiendo (stem change)
Estaba estudiando para el examen cuando me llamaste.
I was studying for the exam when you called me.
Mi padre estaba durmiendo la siesta y no oyó el portazo.
My dad was taking a nap and didn't hear the slammed door.
Never *estaba estudiar, *estaba comer, *estaba vivir. The gerundio is non-negotiable in the progressive periphrasis.
A quick decision flow
When you want to express English "was doing" in Spanish, ask:
- Is the verb stative (saber, conocer, tener, querer, parecer, ser, estar, ver, oír)? → Use the simple imperfect. Sabía, tenía, quería, parecía. The progressive is ungrammatical.
- Is this a narrative chain of ongoing actions setting the scene? → Simple imperfect for all of them. Llovía, yo escribía, el gato dormía…
- Do you want to emphasise the active, in-progress, mid-action quality? → Estaba
- gerundio. Estaba leyendo en mitad de la frase cuando…
- Default case (one ongoing action, one punctual interruption, no special emphasis)? → Simple imperfect for the ongoing, preterite for the interruption. Cenaba cuando llegó.
In practice, options 1, 2, and 4 cover the vast majority of cases — meaning the simple imperfect wins about four times out of five.
Vosotros forms in this construction
The peninsular vosotros imperfect endings show up constantly in this kind of "what were you doing when…" question:
¿Qué hacíais cuando llamé? Nadie me cogió el teléfono.
What were you guys doing when I called? Nobody picked up.
¿Estabais cenando todavía? Perdón por la hora.
Were you guys still having dinner? Sorry about the time.
Mientras vosotros veíais la peli, nosotros preparábamos el postre.
While you guys were watching the film, we were preparing dessert.
The endings -abais (for -ar verbs: cenabais, preparabais) and -íais (for -er/-ir: hacíais, veíais) are how the vosotros shows up in ongoing-past contexts. Note the accent on í in -íais — without it, the form is misspelled.
Common mistakes
❌ Estaba estudiar cuando me llamaste.
Wrong: *estar* takes the gerundio, never the infinitive. *Estaba estudiar* is ungrammatical.
✅ Estudiaba cuando me llamaste.
Correct (simple imperfect, the natural default).
✅ Estaba estudiando cuando me llamaste.
Also correct, with emphasis on the in-progress nature.
❌ Yo estaba sabiendo que algo iba mal.
Wrong: stative verbs (saber, conocer, tener…) don't take the progressive. *Estaba sabiendo* is not Spanish.
✅ Yo sabía que algo iba mal.
Correct: I knew something was wrong.
❌ Estaba lloviendo, yo estaba escribiendo y el gato estaba durmiendo cuando sonó el timbre.
Grammatical but unnatural: piling up three progressives in a row sounds like an over-literal translation. Native rhythm uses simple imperfects.
✅ Llovía, yo escribía y el gato dormía cuando sonó el timbre.
Natural: It was raining, I was writing and the cat was sleeping when the doorbell rang.
❌ Mientras tú estabas cocinar, yo estaba poner la mesa.
Wrong twice: both progressives need the gerundio (*cocinando*, *poniendo*). And in this parallel-actions construction, the simple imperfect is cleaner.
✅ Mientras tú cocinabas, yo ponía la mesa.
Correct: While you were cooking, I was setting the table.
❌ ¿Qué estabais haciendo cuando se cortó la luz? Estaba viendo una serie y mi hermano estaba leyendo.
Grammatical but heavy — three progressives in two sentences. Native speakers would shift at least the chain of background actions to the simple imperfect.
✅ ¿Qué hacíais cuando se cortó la luz? Yo veía una serie y mi hermano leía.
More natural: What were you guys doing when the power cut out? I was watching a series and my brother was reading.
Key takeaways
- The Spanish imperfect already carries "was doing" — most English past progressives translate as a simple imperfect, not as estar + gerundio.
- The classic interrupted-action pattern is imperfect + cuando + preterite: Cenaba cuando llegó. The imperfect is the ongoing background; the preterite is the punctual interruption.
- Parallel ongoing actions both go in the imperfect: Mientras yo cocinaba, mi pareja ponía la mesa.
- Estar
- gerundio (estaba estudiando) is real Spanish but narrower than the English past progressive. Use it for emphasis on active engagement, snapshot moments, or contrast with the action's edges — not as the default.
- Stative verbs (saber, conocer, tener, querer, parecer, ver, oír) cannot take the progressive. They always use the simple imperfect for the ongoing reading.
- Never combine estar with a bare infinitive (*estaba estudiar). The gerundio (-ando / -iendo) is obligatory.
- Peninsular vosotros forms in this construction: hacíais, cenabais, veíais, estabais
- gerundio.
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Start learning Spanish→Related Topics
- Imperfecto para acciones habitualesA2 — The imperfect's bread-and-butter use: things you used to do in the past, things you would do on a regular basis, patterns and routines that repeated themselves. If English would say 'used to' or habitual 'would', Spanish uses the imperfect.
- Acción interrumpida: imperfecto + pretéritoB1 — The classic two-clause pattern: a longer ongoing action in the imperfect gets interrupted by a punctual event in the preterite. 'Estudiaba cuando llamó mi madre.' Master the cuando/mientras templates and you will never sound monotone in past-tense Spanish again.
- Imperfecto para descripcionesA2 — The imperfect is the descriptive tense of past Spanish: physical appearance, character, emotional state, weather, settings, the look and feel of a moment. Where the preterite advances a story, the imperfect paints the scenery against which the story unfolds.
- Imperfecto: verbos regulares en -er e -irA2 — The regular -er and -ir imperfect — endings -ía, -ías, -ía, -íamos, -íais, -ían, with the obligatory accent on every form, including the peninsular vosotros comíais and vivíais.
- Cuándo usar el progresivo en españolA2 — When to actually use estar + gerundio in Spanish — a much narrower window than English 'I am -ing'. Action in progress right now, not general activities, not future plans.