The imperfect tense of irregular verbs

Pretérito imperfecto of ser, ir and ver – what is it for?

• We use the imperfect to talk about the past as a background:
  • habitual actions: what you used to do regularly
  • descriptions in the past: what something or someone was like

With these three verbs:

• ser – what someone/something was like
• ir – where someone used to go
• ver – what someone used to see

1. The three irregular patterns at a glance

• ser and ir are fully irregular.
• ver is almost regular: keep ve- and add normal imperfect endings (-ía, -ías, ...).

2. When do I choose the imperfect (and not another past)?

• Use the imperfect when you can add in English:
  • “used to …”
  • “would … (every day)” (in a repetitive sense)
  • or a long description: “was / were” as a background

Typical time expressions that signal the imperfect:

• siempre – always
• normalmente – normally
• todos los días / cada semana – every day / each week
• antes – before / in the past
• cuando era niño/a – when I was a child

Compare:

• Ellos eran voluntarios muy buenos.
  They were very good volunteers (in general, over a period).
• Ellos fueron voluntarios muy buenos. – sounds like one completed, specific moment, not a general description.

3. Meaning of each verb in the imperfect

• ser – descriptions, identity, permanent characteristics in the past:
  • La ambulancia era lenta. – The ambulance used to be slow.
  • Mi jefa era muy paciente. – My boss was very patient.
• ir – repeated movement, routine destinations:
  • Íbamos al hospital cada mañana. – We used to go to the hospital every morning.
  • Yo iba a urgencias en metro. – I used to go to the ER by metro.
• ver – things you regularly saw / watched:
  • Veía muchas ambulancias. – I used to see many ambulances.
  • Veíamos casos difíciles. – We would see difficult cases.

4. Typical mistakes and how to avoid them

• 1. Mixing up person (yo / tú / él ...)
  • Check that the verb form matches the subject.
  • Tú eras voluntario. (you were)
    Tú era voluntario. ✗
  • Nosotros íbamos al hospital. (we used to go)
    Nosotros iba al hospital. ✗
• 2. Forgetting the accent
  • Accents change pronunciation and, sometimes, meaning.
  • éramos (we were), íbamos (we used to go)
  • Without accent: eramos, ibamos – incorrect forms.
• 3. Confusing imperfect with simple past
  • imperfect: long, repeated, background.
    Cuando trabajaba en el hospital, siempre ayudaba a los pacientes.
  • simple past (pretérito indefinido): one completed action.
    Un día ayudé a un paciente muy famoso. – one finished event.

5. Simple step-by-step: choose the correct form

1. Identify the verb you need:
   • description → ser
   • movement / going somewhere → ir
   • seeing / watching → ver
2. Find the subject (who?):
   • yo, tú, él/ella, nosotros, vosotros, ellos
3. Match subject + correct form in the table.
   • “we used to go” → verb ir, subject nosotros → íbamos
   • “they were” → verb ser, subject ellos → eran
   • “did you see (regularly)” → verb ver, subject tú → veías

6. Quick self-check: do I really need the imperfect?

Ask yourself these questions. If you answer “yes”, the imperfect is probably correct.

• Was it a routine?
  • “I used to go there every day.” → iba
• Is it a description, not an event?
  • “The paramedics were very calm.” → eran
• Did it last for some time?
  • “When I worked in emergencies, I always saw accidents.” → veía

7. Mini practice for self-study

Complete mentally, then check with the table.

1. Antes, yo ___ voluntario en la Cruz Roja. (ser)
2. De niño, tú ___ a urgencias con tus padres. (ir)
3. En el hospital, nosotros ___ muchas ambulancias cada día. (ver)
4. Ellos ___ muy buenos enfermeros. (ser)

Expected answers:

• 1. era
• 2. ibas
• 3. veíamos
• 4. eran

8. What you should pay attention to

• Use imperfect for habits and descriptions in the past.
• Memorise the three sets: era / iba / veía as your anchor forms (yo).
• Always check:
  • subject (who?)
  • correct irregular form (from the table)
  • accent marks (éramos, íbamos, veías, veían...)

If you can say the sentence naturally in English with “used to …” or a long “was / were” description, you are almost always safe with the imperfect forms ser / ir / ver.