Introduction

Yacer means “to lie (down”, and this page covers exactly one thing: yacer in the preterite tense. The preterite is the tense Spanish speakers reach for when they talk about what is finished and done. On this page you will find the full preterite table for yacer, how the tense is formed for this verb, the situations where it is used, how it differs from the imperfect, worked examples, the mistakes learners make most often, an eight-question quiz with explained answers, and answers to the questions students ask about yacer in the preterite. Yacer in the preterite describes one finished action in the past. For example: “Yo yací aquí” — "I lay (down here". Everything on this page uses the forms of yacer exactly as they are conjugated in the preterite, so you can trust every form you see here.

Yacer in the Preterite Tense — full table

Person Form
yo yací
tú yaciste
él/ella/Ud. yació
nosotros/as yacimos
vosotros/as yacisteis
ellos/ellas/Uds. yacieron

Gerund: yaciendo · Past participle: yacido

The gerund is yaciendo, which you use with estar to say what is happening right now: “Estoy yaciendo” means the action of yacer is in progress at this very moment. The past participle is yacido, which you use with haber in the perfect tenses: “he yacido” is the present perfect, used for a completed action. Keep both forms in mind as you read the examples below, because the preterite is only one part of how yacer is used.

How the preterite of yacer is formed

Yacer is regular in the preterite, even though it is irregular in the present. Take the stem yac and add the preterite endings for -er verbs: -í, -iste, -ió, -imos, -isteis, -ieron, giving yací, yaciste, yació, yacimos, yacisteis, yacieron. Watch the accents: yo takes an accent on the í (yací) and él takes one on the ó (yació). The irregularity of yacer is in its present tense (yazco), not in the preterite, so the table above is fully regular. The preterite of yacer is fully regular in its endings, but two details deserve attention. First, the accents: yací carries an accent on the í, and yació carries one on the ó, because the stress falls on the ending rather than the stem. Second, the nosotros form yacimos is identical to the present-tense nosotros form, so only the surrounding words tell you which tense is meant.

When to use the preterite of yacer

The preterite is not a single-purpose tense. Below are the five situations where you will use yacer in the preterite most often. Each one comes with a real example, so read the rule, then say the example out loud.

1. One finished action

The preterite is the tense of one finished action. When something started and ended in the past, with a clear end, yacer goes in the preterite. Example: “Yo yací en paz” — "I lay (down in peace".

2. A sequence of events

When several things happened one after another, each one goes in the preterite. The preterite moves the story from one event to the next, in order. Example: “Desde 1950, él yació” — "Since 1950, he lay (down".

3. A completed time frame

When the action happened inside a finished period of time — ayer, anoche, la semana pasada, el mes pasado — the preterite is the right choice, and yacer follows the same rule. Example: “Yo yací aquí” — "I lay (down here".

4. A sudden change

The preterite also marks a sudden change or the start of a new state. Something changed at one moment, and the preterite names that moment. Example: “Él yació en paz” — "He lay (down in peace".

5. A specific point in time

When you can point to the exact moment something happened — a las nueve, a medianoche, en 2019 — the preterite counts it as one event at that point in time. Example: “Desde 1950, nosotros yacimos” — "Since 1950, we lay (down".

Preterite Tense vs Imperfect: how to choose

The closest tense to the preterite is the imperfect, and choosing between them is one of the hardest decisions in Spanish. The rule is simple: the preterite reports one finished action, while the imperfect describes background, habits in the past, or an action that was in progress when something else happened. The three pairs below use the same verb, so the only thing that changes is whether the action is finished and counted, or ongoing and descriptive. Time words help: ayer and de repente point to the preterite, while mientras and todos los días in the past point to the imperfect.

  • Preterite Tense: “Yo yací aquí” — "I lay (down here".

  • Imperfect: “Yo yacía aquí” — "I used to lie (down here".

  • The preterite sentence counts one finished action; the imperfect sentence describes how things used to be. That difference — finished event versus background — is the whole decision.

  • Preterite Tense: “Él yació en paz” — "He lay (down in peace".

  • Imperfect: “Él yacía en paz” — "He used to lie (down in peace".

  • The preterite sentence counts one finished action; the imperfect sentence describes how things used to be. That difference — finished event versus background — is the whole decision.

  • Preterite Tense: “Desde 1950, nosotros yacimos” — "Since 1950, we lay (down".

  • Imperfect: “Desde 1950, nosotros yacíamos” — "Since 1950, we used to lie (down".

  • The preterite sentence counts one finished action; the imperfect sentence describes how things used to be. That difference — finished event versus background — is the whole decision.

Example sentences: yacer in the preterite

Read these eight sentences out loud. They cover all six persons, so by the end you will have seen every form in the table used in a real sentence. Pay attention to the words around the verb — the time expressions, the objects, the other verbs — because those are what make each sentence sound natural.

  1. “Yo yací en paz” — "I lay (down in peace"

  2. “Desde 1950, tú yaciste” — "Since 1950, you lay (down"

  3. “Él yació aquí” — "He lay (down here"

  4. “Nosotros yacimos en paz” — "We lay (down in peace"

  5. “Desde 1950, vosotros yacisteis” — "Since 1950, you lay (down"

  6. “Ellos yacieron aquí” — "They lay (down here"

  7. “Yo yací en paz” — "I lay (down in peace"

  8. “Desde 1950, él yació” — "Since 1950, he lay (down"

Common mistakes with yacer in the preterite

These are the errors learners actually make with this verb in this tense. Each one shows the wrong version, the right version, and why the correction matters.

  • Wrong: “Ellos yació aquí” Right: “Ellos yacieron aquí” Why: Ellos needs the ellos form yacieron. The singular yació belongs with él, ella or a singular noun.

  • Wrong: “Ayer, yo yazco” Right: “Ayer, yo yací” Why: The present tense cannot describe a finished action yesterday. Ayer forces the preterite, so the form must change to yací.

  • Wrong: “Ayer, yo yacía” Right: “Ayer, yo yací” Why: Ayer names one finished day, so the preterite is right. The imperfect (yacía) describes background or a habit, not one finished action.

  • Wrong: “Nosotros yaciste aquí.” Right: “Nosotros yacimos aquí” Why: Nosotros needs yacimos. The tú form yaciste belongs with tú.

Quiz: yacer in the preterite

Choose the correct answer for each question, then check the answer key. Every answer is explained, so a wrong answer still teaches you something.

1. Complete the sentence: “Yo ___ aquí.” (yo form)

A. yací B. yacimos C. yació D. yacisteis

2. Complete the sentence: “Tú ___ en paz.” (tú form)

A. yací B. yació C. yaciste D. yacieron

3. Complete the sentence: “Él ___ aquí.” (él/ella/Ud. form)

A. yací B. yació C. yacisteis D. yaciste

4. Complete the sentence: “Nosotros ___ en paz.” (nosotros/as form)

A. yací B. yació C. yacimos D. yacieron

5. Complete the sentence: “Vosotros ___ aquí.” (vosotros/as form)

A. yació B. yacimos C. yaciste D. yacisteis

6. Complete the sentence: “Ellos ___ en paz.” (ellos/ellas/Uds. form)

A. yaciste B. yacieron C. yacimos D. yací

7. Which time expression points to the preterite tense?

A. ayer B. todos los días C. cada semana D. mientras

8. Which sentence is correct?

A. Ayer, yo yací B. Ayer, yo yacía

Answer key

  1. yací — The yo preterite of yacer is yací.
  2. yaciste — The tú preterite of yacer is yaciste.
  3. yació — The él/ella/Ud. preterite of yacer is yació.
  4. yacimos — The nosotros/as preterite of yacer is yacimos.
  5. yacisteis — The vosotros/as preterite of yacer is yacisteis.
  6. yacieron — The ellos/ellas/Uds. preterite of yacer is yacieron.
  7. ayer — Ayer names one finished day, so the preterite is right. Todos los días, cada semana and mientras point to the present or the imperfect.
  8. Ayer, yo yací — Ayer is one finished day, so the preterite is correct. The imperfect describes background or a habit.

Frequently asked questions

When do I use the preterite of yacer?

Use the preterite for one finished action in the past. For example: Yo yací aquí. If the action is finished and counted, the preterite is the right choice.

How is the preterite of yacer formed?

Take the stem yac- and add the preterite endings for -er verbs (-í, -iste, -ió, -imos, -isteis, -ieron), giving yací, yaciste, yació, yacimos, yacisteis, yacieron.

What is the difference between the preterite and the imperfect for yacer?

The preterite (yací) counts one finished action, while the imperfect (yacía) describes background or a habit in the past. Compare the two sentences in the contrast section above: the verb is the same, only the tense changes.

How can I practise yacer in the preterite?

Say the six forms out loud — yací, yaciste, yació, yacimos, yacisteis, yacieron — then use them in the example sentences above, changing the person each time. Then try the yacer examples and quiz page, and the full conjugation of yacer when you want to compare the preterite with the other tenses.

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