1. First Category: -ir Ending Verbs
  2. Second Category: Stem-Changing Verbs
  3. Third Category: Verbs with Changes to Maintain Pronunciation

In the preterite, there are three main categories of irregular that change their stem when conjugated. It is important to become familiar with them to use them correctly.



Creo que hicieron un gran trabajo, estoy segura que el cliente se sintió feliz.

I think they did a great job, I'm sure the client was happy.

First Category: -ir Ending Verbs

Rule 1. Irregular verbs ending in -ir are modified only in the third person singular (él, ella, usted) and plural (ellos, ellas, ustedes), while the other persons follow the regular preterite pattern for verbs ending in -ir.

They may change the e of their stem to i, as in the case of the verb pedir.



Él pidió un aumento en su trabajo.

He asked for a raise in his job.

Other verbs that follow this pattern are: sentir, preferir, repetir, seguir, servir, and vestirse.

Subject Pronounsentirpreferirrepetirseguirservirvestirse
yo sentí preferí repetí seguí serví me vestí
sentiste preferiste repetiste seguiste serviste te vestiste
él, ella, usted* sintió prefirió repitió siguió sirvió se vistió
nosotros, nosotras sentimos preferimos repetimos seguimos servimos nos vestimos
vosotros, vosotras sentisteis preferisteis repetisteis seguisteis servisteis os vestisteis
ellos, ellas, ustedes* sintieron prefirieron repitieron siguieron sirvieron se vistieron

Verbs in this group can also change the o in their stem to u, as in the case of the verb dormir.



Estaban cansados entonces durmieron toda la noche.

They were tired so they slept all night.

Second Category: Stem-Changing Verbs

Rule 2. Some verbs have completely irregular stems but share the same endings and some changes in their stem, and can be grouped into three categories. The irregular stem also applies to all the persons.

They share the following endings:

Subject PronounEndings
yo -e
él, ella, usted -o
nosotros, nosotras -imos
vosotros, vosotras -isteis
ellos, ellas, ustedes -ieron
  • First group: i stem-changing verbs

Rule 3. Verbs such as hacer, querer, and venir change a vowel in their stem to i.

Subject PronounHacerQuererVenir
yo hice quise vine
hiciste quisiste veniste
él, ella, usted hizo* quiso vino
nosotros, nosotras hicimos quisimos venimos
vosotros, vosotras hicisteis quisisteis venisteis
ellos, ellas, ustedes hicieron quisieron vinieron
  • Second group: -u stem-changing verbs

Rule 4. Verbs such as estar, poder, poner, saber, and tener change a vowel in their stem to u.

Subject PronounEstarPoderPonerSaberTener
yo estuve pude puse supe tuve
estuviste pudiste pusiste supiste tuviste
él, ella, usted estuvo pudo puso supo tuvo
nosotros, nosotras estuvimos pudimos pusimos supimos tuvimos
vosotros, vosotras estuvisteis pudisteis pusisteis pusisteis tuvisteis
ellos, ellas, ustedes estuvieron pudieron pusieron supieron tuvieron
  • Third group: j stem-changing verbs

Rule 5. Verbs such as decir, traducir and conducir change their c to j.

Subject PronounDecirTraducirConducir
yo dije traduje conduje
dijiste tradujiste condujiste
él, ella, usted dijo tradujo condujo
nosotros, nosotras dijimos tradujimos condujimos
vosotros, vosotras dijisteis tradujisteis condujisteis
ellos, ellas, ustedes dijeron tradujeron condujeron

Third Category: Verbs with Changes to Maintain Pronunciation

Sometimes, it is necessary to change the final consonant of the stem in the first person singular of verbs ending in -ar to maintain the pronunciation in the infinitive form.

Rule 6. Change c to qu, as in the verb atacar.



Yo ataqué al equipo contrario.

I attacked the opposing team.

Rule 7. Change g to gu, as in the verb colgar.



Ayer colgué el cuadro.

Yesterday I hung the painting.

Rule 8. Change z to c, as in the verb comenzar.



Hace dos semanas comencé a estudiar Japonés.

Two weeks ago I started studying Japanese.



Ayer ellos ________ (hacer) un pastel para la fiesta.


correct answers.