Decaer in the Preterite Tense
Decaer means “to decline, to weaken”, and this page covers exactly one thing: decaer 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 decaer, 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 decaer in the preterite. For example: “Ayer, yo decaí con la edad y la enfermedad.” — Yesterday, I declined with age and illness. Everything on this page uses the forms of decaer exactly as they are conjugated in the preterite, so you can trust every form you see here.
Decaer in the Preterite Tense — full table
| Person | Form |
|---|---|
| yo | decaí |
| tú | decaíste |
| él/ella/Ud. | decayó |
| nosotros/as | decaímos |
| vosotros/as | decaísteis |
| ellos/ellas/Uds. | decayeron |
Gerund: decayendo · Past participle: decaído
The gerund is decayendo, which you use with estar to say what is happening right now: “Estoy decayendo” means the action of decaer is in progress at this very moment. The past participle is decaído, which you use with haber in the perfect tenses: “he decaído” 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 decaer is used.
How the preterite of decaer is formed
Decaer is regular in the preterite tense. Take the stem deca and add the preterite endings for -er verbs: -í, -íste, -yó, -ímos, -ísteis, -yeron, giving decaí, decaíste, decayó, decaímos, decaísteis, decayeron. Watch the accents: the yo form is decaí and the él/ella/Ud. form is decayó.
When to use the preterite of decaer
The preterite is not a single-purpose tense. Below are the five situations where you will use decaer 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 reports a single action that started and finished in the past. The action is done, counted once, and the story moves on. Example: “Ayer, yo decaí con la edad y la enfermedad.” — Yesterday, I declined with age and illness.
2. A sequence of events
In a story, each preterite form is one step forward in time. When several things happened one after another, the preterite lists them in order. Example: “Nosotros decaímos poco a poco tras la crisis.” — We declined little by little after the crisis.
3. A specific time marker
Time words such as ayer, anoche, el año pasado and la semana pasada point to the preterite. They name a finished moment, and the verb must match. Example: “Él decayó el interés por el proyecto ayer.” — He declined interest in the project yesterday.
4. A sudden change or interruption
The preterite describes sudden changes and interruptions: something happened, and the situation was different afterwards. Example: “Ellos decayeron la economía del país de repente.” — They declined the country's economy suddenly.
5. A completed time frame
When an action took place inside a period of time that is now over, the preterite is the right tense, because the period itself is finished. Example: “Tú decaíste con la edad y la enfermedad la semana pasada.” — You declined with age and illness last week.
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: “Ayer, yo decaí con la edad y la enfermedad.” — Yesterday, I declined with age and illness.
Imperfect: “Yo decaía con la edad y la enfermedad cada día.” — I used to decline with age and illness every day.
The preterite sentence reports one finished action; the imperfect sentence describes a habit in the past. Ayer points to the preterite, cada día in the past points to the imperfect.
Preterite Tense: “Anoche, él decayó poco a poco tras la crisis.” — Last night, he declined little by little after the crisis.
Imperfect: “Él decaía poco a poco tras la crisis todos los días.” — He used to decline little by little after the crisis every day.
Anoche names one finished night, so the preterite is right; todos los días in the past describes a routine, so the imperfect is right.
Preterite Tense: “Nosotros decaímos el interés por el proyecto ayer.” — We declined interest in the project yesterday.
Imperfect: “Nosotros decaíamos el interés por el proyecto cuando éramos jóvenes.” — We used to decline interest in the project when we were young.
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: decaer 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.
“Decaí con la edad y la enfermedad.” — I declined with age and illness.
“Decaíste poco a poco tras la crisis.” — You declined little by little after the crisis.
“Decayó el interés por el proyecto.” — He/she declined interest in the project.
“Decaímos la economía del país.” — We declined the country's economy.
“Decaísteis con la edad y la enfermedad.” — You declined with age and illness.
“Decayeron poco a poco tras la crisis.” — They declined little by little after the crisis.
“Decaí el interés por el proyecto.” — I declined interest in the project.
“Decayó la economía del país.” — He/she declined the country's economy.
Common mistakes with decaer 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 decayó con la edad y la enfermedad.” Right: “Ellos decayeron con la edad y la enfermedad.” Why: Ellos needs the ellos form decayeron. The singular decayó belongs with él, ella or a singular noun.
Wrong: “De niño, yo decaí el interés por el proyecto todos los días.” Right: “De niño, yo decaía el interés por el proyecto todos los días.” Why: For a repeated habit in the past, use the imperfect (decaía), not the preterite. The preterite (decaí) is for one finished action.
Wrong: “Nosotros decaíste el interés por el proyecto.” Right: “Nosotros decaímos el interés por el proyecto.” Why: Nosotros needs decaímos. The tú form decaíste belongs with tú.
Wrong: “Ellos decaí la economía del país.” Right: “Ellos decayeron la economía del país.” Why: The verb must agree with its subject. Ellos needs the ellos form decayeron, not the yo form decaí.
Quiz: decaer 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 ______ con la edad y la enfermedad.” (With age and illness.)
- (a) decaí
- (b) decaíste
- (c) decayó
Answer: decaí — The yo form of decaer in the preterite is decaí. The other options are the forms for different persons, so they do not agree with the subject.
2. Complete the sentence: “¿Tú ______ poco a poco tras la crisis?” (Little by little after the crisis.)
- (a) decaí
- (b) decayó
- (c) decaíste
Answer: decaíste — The tú form of decaer in the preterite is decaíste. The other options are the forms for different persons, so they do not agree with the subject.
3. Complete the sentence: “Él ______ el interés por el proyecto.” (Interest in the project.)
- (a) decaíste
- (b) decayó
- (c) decaí
Answer: decayó — The él/ella/Ud. form of decaer in the preterite is decayó. The other options are the forms for different persons, so they do not agree with the subject.
4. Complete the sentence: “Nosotros ______ la economía del país.” (The country's economy.)
- (a) decaímos
- (b) decaí
- (c) decaíste
Answer: decaímos — The nosotros/as form of decaer in the preterite is decaímos. The other options are the forms for different persons, so they do not agree with the subject.
5. What is the vosotros/as form of decaer in the preterite?
- (a) decaí
- (b) decaíste
- (c) decaísteis
Answer: decaísteis — From the table above: vosotros/as takes decaísteis. Say it with the example sentence “Vosotros decaísteis con la edad y la enfermedad.” to fix it in your memory.
6. Complete the sentence: “Ellos ______ poco a poco tras la crisis.” (Little by little after the crisis.)
- (a) decaíste
- (b) decayeron
- (c) decaí
Answer: decayeron — The ellos/ellas/Uds. form of decaer in the preterite is decayeron. The other options are the forms for different persons, so they do not agree with the subject.
7. Which is the correct yo form of decaer in the preterite?
- (a) decaí
- (b) decaíste
- (c) decayó
Answer: decaí — The yo form is decaí. The other two options are the forms for other persons.
8. Which sentence describes one finished action in the past?
- (a) Yo decaía con la edad y la enfermedad cada día.
- (b) Mañana, yo decaeré con la edad y la enfermedad.
- (c) Ayer, yo decaí con la edad y la enfermedad.
Answer: Ayer, yo decaí con la edad y la enfermedad. — “Ayer, yo decaí con la edad y la enfermedad.” reports a single completed event, so it takes the preterite. The second option describes background or a past habit, and the third looks to the future.
Frequently asked questions
Is decaer regular in the preterite?
Decaer is a spelling-change verb, so some forms change spelling to keep the same consonant sound, but the preterite forms in the table above are the correct ones: decaí, decaíste, decayó, decaímos, decaísteis, decayeron.
What is the past participle of decaer?
The past participle is decaído: 'He decaído' means 'I have declined'. It is used with haber in every perfect tense. The gerund is decayendo.
When do I use the preterite instead of the imperfect for decaer?
Use the preterite for one finished action, as in Ayer, yo decaí con la edad y la enfermedad. Use the imperfect for a repeated habit or background, as in Yo decaía con la edad y la enfermedad cada día. The time words around the verb usually tell you which one fits.
How do I remember the preterite forms of decaer?
Say the six forms out loud in order, three times, with a real sentence for each one: yo decaí, tú decaíste, él/ella/Ud. decayó, nosotros/as decaímos, vosotros/as decaísteis, ellos/ellas/Uds. decayeron. Then write three of your own sentences with decaer in the preterite, using the examples on this page as models.
Related pages
- Full conjugation of decaer — every tense of decaer in one place.
- Decaer examples and quiz — more sentences with decaer and a ten-question quiz.
- Spanish preterite guide — how the preterite works for all Spanish verbs.
- Spanish verbs — the hub for every Spanish verb on VerbFlow.
- Preterite conjugator — conjugate any verb in the preterite instantly.
- Verb quiz — test yourself on decaer and other verbs.