Match the type of preterite stem change with the verb
dormir:
Answer: o-u : durmió , durmieron (3rd person singular and plural )
repetir:
Answer: e-i : repitió , repitieron (3rd person singular and plural )
preferir:
Answer: e-i : prefirió , prefirieron (3rd person singular and plural )
leer:
Answer: i-y : leyó , leyeron (3rd person singular and plural )
caerse:
Answer: i-y : se cayó , se cayeron (3rd person singular and plural )
servir:
Answer: e-i : sirvió , sirvieron (3rd person singular and plural )
Explanation:
The –ir verbs that change the stem in the present tense (dormir, repetir, preferir, servir), in the preterite, they only change the stem in the 3rd person singular and plural and they always follow the same pattern. The "o" changes to "u" or the "e" changes to "i".
If the stem of an –er verb ends in a vowel, you need to change the ending for the 3rd person (singular and plural) in the preterite: The "i" changes to "y".
Spymore