The preterite is one of the two simple past tenses in Spanish. It is used when the speaker wants to focus on the beginning or ending of an action in the past.

If a verb is a stem changer in the present tense, it will not stem-change in the preterit unless it is an - ir verb. No - ar or - er verbs will stem-change in the preterit.

The verb dormir (to sleep) is an ir verb that undergoes a stem change from (o) to (ue). The congugation of dormir is shown in the table below.

dormir (example sentences) (full conjugation)

   
yo
   
dormí
   
(I slept)


   
tú
   
dormiste
   
(you slept)


   
Ud./él/ella
   
durmió
   
(you/he/she slept)


   
nosotros as
   
dormimos
   
(we slept)


   
vosotros as
   
dormisteis
   
(you guys slept)


   
Uds./ellos/ ellas
   
durmieron
   
(you all/they slept)

Note:
m = male f = female mix = mixed group
yo = I, tú = you (informal)
usted (Ud.) = you (formal)
él = he, ella = she
nosotros = we (m/mix), nosotras = we (f)
vosotros = you guys (informal, m/mix)
vosotras = you guys (informal, f)
ellos = they (m/mix), ellas = they (f)
ustedes (Uds.) = you all (formal)