CONJUGUEMOS REFERENCE

PRETERITE: Stem-Changing: o - u

Rules:

Stem-changing verbs that end in -ir have a stem-change in the third person of the preterite. The pattern of the change resembles a sandal, so these verbs are also called "sandal" verbs. In this pattern, verbs that are O->UE in the present tense change O->U in the preterit in the third person:

o->u

dormir: to sleep

dormí dormimos
dormiste dormisteis
durmió durmieron