The imperfect tense or the simple past?

1. The key idea: finished event vs. background / habit

In Spanish past tenses, first think about the function of the verb in the story:

• Pretérito indefinido = the main events. What happened? When did it start and finish?
• Pretérito imperfecto = the background. What was it like? What was going on regularly or in progress?

Imagine a film:

• Imperfecto = the long camera shot, the atmosphere, the routine.
• Indefinido = the short, important actions that move the story forward.

2. Use of pretérito indefinido (simple past events)

Ask yourself: “Is this a finished action at a specific time?”

• One clear action, finished:
  Aprobé el máster en 2022.
• A sequence of events:
  El profesor suspendió la clase, llamó al director y se fue a casa.
• Something that happened once or a specific number of times:
  Una vez llegué tarde al examen.

Typical time expressions that often go with indefinido:

• ayer, anteayer
• el lunes pasado, el año pasado, en 2019
• una vez, dos veces

3. Use of pretérito imperfecto (background, habits, descriptions)

Ask yourself: “Am I talking about background, habit, or something in progress?”

• Habits and routines in the past:
  Siempre enseñaba en la escuela primaria. (He/she used to teach there.)
• Descriptions of places, people, situations:
  La escuela era antigua y tenía un patio grande.
• Actions in progress when something else happened:
  Mientras estudiaba, sonó el teléfono.
• Age, time, feelings in the past (usually background):
  Tenía 10 años y estaba muy nervioso.

Typical expressions that often go with imperfecto:

• siempre, normalmente, a menudo, todos los días
• cuando era niño / estudiante
• en esa época, antes

4. Putting them together: context (imperfecto) + action (indefinido)

Very often you need both in one sentence or paragraph.

• Imperfecto = the situation, the “frame”.
• Indefinido = what actually happened inside that frame.

Together: Mientras veníamos de clase, llamó mi madre.

5. Typical confusion: English vs. Spanish

• In English, we often use simple past for both habits and single events:
  I went to the gym every day.
• In Spanish, you must choose: habit or single event?

So a sentence like:

• Cuando era estudiante, fui al gimnasio todos los días.
• Correct: Cuando era estudiante, iba al gimnasio todos los días.

“Every day” = habit → use iba (imperfecto).

6. Quick decision guide: 3 questions

When you choose between indefinido and imperfecto, ask:

1. Is the action finished and limited in time?
   – Yes → probably indefinido.
   – No / not important → go to 2.
2. Is it a habit or repeated action?
   – Yes → imperfecto.
   – No → go to 3.
3. Is it description or background? (age, weather, place, situation, feelings)
   – Yes → imperfecto.
   – No → usually indefinido.

7. Self-check: can you explain these to yourself?

Try to say the answers in your own words. If you can, you probably understand the topic.

1. Why do we say: Siempre desayunaba café antes de ir al trabajo, and not Siempre desayuné café…?
2. In the sentence Mientras estudiaba, sonó el teléfono, which verb is background and which is the main event? Why?
3. How would you translate to Spanish: “When I was a child, I played the piano every day”? Would you choose tocaba or toqué? Why?
4. Can you make one sentence about your school days that has both tenses? (Background in imperfecto + one specific action in indefinido.)

8. What to pay special attention to

• Time words: be careful when you mix words like siempre (habit) with ayer (one specific day). Usually you need either a habit idea or a specific-moment idea, not both.
• English interference: if English uses one simple past, Spanish may still need two different tenses.
• Story structure: when you tell a story, plan your background first (imperfecto), then add the concrete events (indefinido).
• Both tenses in one text is normal and expected. Don’t try to “stay in one tense”.

If you can identify background vs. action and habit vs. single event in your own sentences, you are using pretérito imperfecto and pretérito indefinido correctly.