Certain time expressions are so strongly associated with one tense or the other that you can use them as shortcuts. If you see ayer, your brain should reach for the preterite; if you see siempre, the imperfect. These markers are not absolute rules, but they are reliable enough that memorizing them will speed up your tense choices.
Preterite markers
The preterite loves time expressions that close an event — a specific day, a finished stretch, or a number of times.
| Spanish | English |
|---|---|
| ayer | yesterday |
| anoche | last night |
| anteayer / antier | the day before yesterday |
| el lunes pasado | last Monday |
| la semana pasada | last week |
| el mes pasado | last month |
| el año pasado | last year |
| en 1990 | in 1990 |
| hace dos años | two years ago |
| de repente | suddenly |
| una vez | once, one time |
| dos veces | twice |
| por fin | finally |
| esta mañana | this morning |
El verano pasado visitamos Costa Rica por primera vez.
Last summer we visited Costa Rica for the first time.
De repente, alguien apagó la luz.
Suddenly, someone turned off the light.
Imperfect markers
The imperfect pairs naturally with expressions of frequency, routine, and long duration. These words set up the expectation that an action repeated or went on indefinitely.
| Spanish | English |
|---|---|
| siempre | always |
| todos los días | every day |
| todas las mañanas | every morning |
| todos los sábados | every Saturday |
| cada año | each year |
| frecuentemente / a menudo | frequently, often |
| generalmente | generally |
| normalmente | normally |
| a veces | sometimes |
| muchas veces | many times |
| mientras | while |
| de niño / de niña | as a child |
| en aquella época | in those days |
| antes | before, formerly |
De niña, siempre jugaba con mis primos en el jardín.
As a girl, I always used to play with my cousins in the garden.
Mientras mi mamá cocinaba, yo ponía la mesa.
While my mom was cooking, I was setting the table.
En aquella época, la gente no tenía celulares.
In those days, people didn't have cell phones.
A subtle warning
Time markers are clues, not commands. It is possible to use siempre with the preterite, but only when you are looking back on a complete stretch of time:
Mi abuelo siempre fue un hombre honesto.
My grandfather was always an honest man.
Here the preterite fue treats the whole life of the grandfather as a closed chapter. The sentence looks at his entire existence from the outside. With era, the sentence would feel more like a description of him while he was alive.
Ambiguous phrases
Some expressions do not lean strongly toward one tense and depend entirely on context:
- cuando (when) — can go with either; see the interrupted actions page
- un día (one day) — often preterite (Un día llegó una carta...), but can be imperfect in generic descriptions
- todo el día (all day) — preterite for a finished day (Estudié todo el día), imperfect for a habitual description
Un día, mientras caminaba por el bosque, vi un venado.
One day, while I was walking through the forest, I saw a deer.
That sentence combines both tenses exactly where you would expect: caminaba as the background, vi as the event.
A quick drill
Read each sentence and decide the tense, using only the time expression as a clue:
- Ayer (comer) pizza. → comí (preterite)
- Todos los viernes (ir) al gimnasio. → iba (imperfect)
- El año pasado (viajar) a Perú. → viajé (preterite)
- De niño (jugar) al fútbol. → jugaba (imperfect)
- Dos veces (hablar) con ella. → hablé (preterite)
These markers are powerful, but the final decision always comes down to aspect: completed event or ongoing context. Use the keywords as a sanity check, not a crutch. Next, look at verbs that change meaning between the two tenses.
Related Topics
- OverviewB1 — Understanding when to use preterite and when to use imperfect — the single biggest challenge of Spanish past tenses.
- Completed vs Habitual ActionsB1 — The same verb, one finished instance vs a repeated routine — and why Spanish makes you choose.
- Usage: Completed ActionsA2 — The preterite's core job is to mark actions as completed, bounded events in the past.
- Usage: Habitual ActionsA2 — Using the imperfect tense to describe habitual, repeated actions in the past — the equivalent of English 'used to do' and 'would do'.