1. Stem - Changing verbs in the preterite
Gramática
Stem - Changing verbs in the preterite

2. Buenas noticias -ar -er no stem changes...yeah!
-ar and -er verbs that change their stem in the present tense DO NOT change their stem in the preterite.
They are conjugated just like other regular preterite verbs, using the regular endings.
-ar -er
no stem changes...yeah!

3. Stem changing verbs that end in -ir
Stem changing verbs (in the present tense) that end in –ir also have a stem change in the third person singular and plural BUT IN A DIFFERENT WAY:
*note: the endings are the same as those of regular –ir verbs

4. E to I preferí preferimos sentí sentimos preferiste preferisteis
prefirió prefirieron
sentí sentimos
sentiste sentisteis
sintió sintieron
Sentir (e to ie in the present tense)
Preferir (e to ie in the present tense)

5. E to I serví servimos serviste servisteis sirvió sirvieron
pedí pedimos
pediste pedisteis
pidió pidieron
servir (e to i in the present tense)
pedir (e to i in the present tense)

6. E to I (me) reí (nos) reímos (te) reíste (os) reísteis
(se) rió (se) rieron
reír(se) (e to i in the present tense)

7. O to U Dormí Dormimos Dormiste Dormisteis Durmió Durmieron
Dormir (o to ue in the present tense)

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