Reforzar Examples, Sentences & Quiz in Spanish

reforzar means "to reinforce" in English, and this page shows you how it actually sounds in everyday Spanish — not just the conjugation table, but the verb in real sentences, in short dialogues, and in the mistakes learners make with it. Reforzar means to strengthen something that already exists: a wall, a team, an idea, a security system. It is used for both physical reinforcement and for arguments and ideas. Below you will find twelve example sentences grouped by use, two short dialogues, the most common mistakes with corrections, and a ten-question quiz with explained answers. If you want the full tables first, start with the full conjugation of reforzar; if you want to study one tense in depth, see the reforzar present tense page.

reforzar in everyday use: examples with translations

Everyday present uses

How the verb sounds in the present, the future and in hypotheticals — the forms you will use most often.

  1. Yo refuerzo los cimientos de la casa — "I reinforce the foundations of the house"
  2. Mi amigo refuerza la seguridad del edificio — "My friend reinforces the building's security"
  3. Mañana, tú reforzarás el equipo con dos jugadores — "Tomorrow, you will reinforce the team with two players"
  4. Yo reforzaría la idea con ejemplos si pudiera — "I would reinforce the idea with examples if I could"

Talking about the past

The same verb in the past: one finished action, a habit, something that has just happened, and something that had already happened.

  1. Ayer, yo reforcé los cimientos de la casa — "Yesterday, I reinforced the foundations of the house"
  2. Antes, nosotros reforzábamos la seguridad del edificio — "Before, we used to reinforce the building's security"
  3. Él ha reforzado el equipo con dos jugadores — "He has reinforced the team with two players"
  4. Yo ya había reforzado la idea con ejemplos antes de salir — "I already had reinforced the idea with examples before leaving"

Wishes, conditions and commands

The verb after espero que, in si clauses, as a command — and in the conditional perfect, for what would have happened.

  1. Espero que él refuerce los cimientos de la casa — "I hope he reinforces the foundations of the house"
  2. Si yo reforzara la seguridad del edificio, todo cambiaría — "If I reinforced the building's security, everything would change"
  3. Refuerza el equipo con dos jugadores. — "Reinforce the team with two players."
  4. Yo habría reforzado la idea con ejemplos con más tiempo — "I would have reinforced the idea with examples with more time"

reforzar in conversation

Two short dialogues that use reforzar the way people really speak it. Notice how the verb changes with the person, and how the same verb fits different situations.

Two friends talk about it.

  • Lucía: Hola, ¿qué tal? — "Hello, how are you?"
  • Lucía: Yo refuerzo los cimientos de la casa — "I reinforce the foundations of the house"
  • Marcos: Él refuerza la seguridad del edificio — "He reinforces the building's security"
  • Lucía: Ayer, yo reforcé el equipo con dos jugadores — "Yesterday, I reinforced the team with two players"
  • Marcos: Mañana, tú reforzarás la idea con ejemplos — "Tomorrow, you will reinforce the idea with examples"

A practical exchange.

  • Marcos: Hola, ¿qué tal? — "Hello, how are you?"
  • Marcos: Refuerza el muro con hormigón. — "Reinforce the wall with concrete."
  • Lucía: Él ha reforzado los cimientos de la casa — "He has reinforced the foundations of the house"
  • Marcos: Espero que él refuerce la seguridad del edificio — "I hope he reinforces the building's security"
  • Lucía: Antes, yo reforzaba el equipo con dos jugadores — "Before, I used to reinforce the team with two players"

Common mistakes with reforzar

The errors learners actually make with reforzar, each with the wrong form, the right form, and why the right form is right.

✗ *Yo reforzo la idea con ejemplos.

✓ Correct: Yo refuerzo la idea con ejemplos.

reforzar is a stem-changing verb (o → ue): the stem vowel changes in the stressed present forms, so the yo form is refuerzo, not reforzo.

✗ *Ayer, yo reforzé el muro con hormigón.

✓ Correct: Ayer, yo reforcé el muro con hormigón.

The z of reforzar becomes c before e, so the preterite yo form is reforcé, never reforzé.

✗ *Espero que él refuerza la idea con ejemplos

✓ Correct: Espero que él refuerce la idea con ejemplos

After espero que, Spanish requires the subjunctive: Espero que él refuerce la idea con ejemplos — not the indicative Espero que él refuerza la idea con ejemplos.

✗ *Ayer, yo refuerzo el muro con hormigón

✓ Correct: Ayer, yo reforcé el muro con hormigón

Ayer points to a finished action in the past, so it needs the preterite: Ayer, yo reforcé el muro con hormigón.

✗ *De niño, yo reforcé los cimientos de la casa todos los días

✓ Correct: De niño, yo reforzaba los cimientos de la casa todos los días

For a repeated habit in the past, use the imperfect, not the preterite: De niño, yo reforzaba los cimientos de la casa todos los días.

Quiz: reforzar in use

Ten questions on reforzar — its forms, its tenses and its everyday use. Choose the best answer for each one, then check the answer key below, where every answer is explained.

  1. Complete the sentence: Yo ______ los cimientos de la casa — "I reinforce the foundations of the house" (present) A. reforzamos B. refuerzo C. refuerzas D. refuerza

  2. Complete the sentence: Ayer, yo ______ la seguridad del edificio — "Yesterday, I reinforced the building's security" (preterite) A. reforcé B. reforzaste C. reforzó D. reforzamos

  3. Complete the sentence: Antes, nosotros ______ el equipo con dos jugadores — "Before, we used to reinforce the team with two players" (imperfect) A. reforzaba B. reforzabas C. reforzabais D. reforzábamos

  4. Complete the sentence: Mañana, tú ______ la idea con ejemplos — "Tomorrow, you will reinforce the idea with examples" (future) A. reforzaré B. reforzará C. reforzaremos D. reforzarás

  5. Complete the sentence: Yo ______ el muro con hormigón — "I would reinforce the wall with concrete" (conditional) A. reforzaría B. reforzarías C. reforzaríamos D. reforzaríais

  6. Complete the sentence: Él ______ los cimientos de la casa — "He has reinforced the foundations of the house" (present perfect) A. he reforzado B. has reforzado C. hemos reforzado D. ha reforzado

  7. Complete the sentence: Espero que él ______ la seguridad del edificio — "I hope he reinforces the building's security" (present subjunctive) A. reforcemos B. reforcéis C. refuerce D. refuerces

  8. Complete the sentence: ______ el equipo con dos jugadores. — "Reinforce the team with two players." (affirmative imperative) A. refuerce B. reforcemos C. reforzad D. refuerza

  9. Which is the gerund of reforzar, used with estar for the progressive? A. reforzado B. refuerzo C. reforcé D. reforzando

  10. What does reforzar mean in English? A. to cross B. to reinforce C. to strengthen D. to enjoy

Answer key

  1. refuerzo — The present form for yo is refuerzo.
  2. reforcé — The preterite form for yo is reforcé.
  3. reforzábamos — The imperfect form for nosotros/as is reforzábamos.
  4. reforzarás — The future form for tú is reforzarás.
  5. reforzaría — The conditional form for yo is reforzaría.
  6. ha reforzado — The present perfect form for él/ella/Ud. is ha reforzado.
  7. refuerce — The present subjunctive form for él/ella/Ud. is refuerce.
  8. refuerza — The affirmative imperative form is refuerza.
  9. reforzando — The gerund of reforzar is reforzando: estoy reforzando. The participle reforzado is used with haber instead.
  10. to reinforce — reforzar means to reinforce.

Frequently asked questions

What does reforzar mean in English?

reforzar means to reinforce. For example: Yo refuerzo los cimientos de la casa — "I reinforce the foundations of the house". The exact English wording depends on the context, but the core meaning stays the same across the tenses.

What preposition goes with reforzar?

reforzar takes its complement directly, with no preposition, as in the examples above. Adding an extra preposition is a common learner error.

Is reforzar regular?

No. reforzar is a stem-changing -ar verb (o → ue). The stem vowel changes in the stressed forms of the present: refuerzo, refuerzas, refuerza and refuerzan — but nosotros and vosotros keep the plain stem: reforzamos, reforzáis.

How do I practise reforzar?

Start with the present tense table on the full conjugation page, then drill the preterite and the imperfect, since those two past tenses cause the most mistakes. Try the Spanish Verb Quiz to test the forms under pressure, and come back to the sentences above until you can say them without looking.

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