1. Stem-changing verbs in the Preterite
Notas de Gramática
Stem-changing verbs
in the Preterite

2. ¿Recuerdas?
Most verbs that make stem-changes in the present tense NEVER make those changes in the preterite…

3. Present-tense (Boot) Verbs
You remember these Boot verbs that you studied in the present tense…
Pensar Querer Dormir
Yo pienso quiero duermo
Tú piensas quieres duermes…

4. Boot Verbs in the Preterite
In the preterite (pretérito) tense…
Boot verbs ending in
AR & - ER NEVER
make stem-changes
So conjugate Pensar as a regular verb in the preterite (pensé, pensaste, pensó, pensamos, pensasteis, ,pensaron)

5. But… -IR will make some changes but They will only stem-change in the
Only stem-changing (boot) verbs that end in
-IR will make some changes but
NOT in the boot forms…
They will only stem-change in the
CIGAR FORMS!
Then they can only change from
E --- I or O ---- U
(never e -- ie or o --- ue! like in the present)

6. Ejemplos… Servir = to serve Dormir = to sleep Yo serví N. servimos
Tú serviste V. servisteis
El/ sirvió ellos sirvieron
Ella ellas
Dormir = to sleep
Yo dormí N. dormimos
Tú dormiste V. dormisteis
El/ durmió ellos durmieron
Ella ellas

7. Ahora… Conjuguemos… Preferir = to prefer
In the present tense.. (e - ie)
Yo prefiero, prefieres, prefiere…
Now conjugate it in the preterite…
Pedir = to ask for/order
In the present tense.. (e - i)
Yo pido, pides, pide..
Now try it in the preterite…

8. Respuestas… Preferir preferí preferimos preferiste preferisteis
prefirió prefirieron
You should memorize these rules tonight!
Pedir
pedí pedimos
pediste pedisteis
pidió pidieron
You will be quizzed over them soon!

9. So which verbs stem-change in the preterite?
Only if it is a boot verb in the present and ends in
-IR
Only in the CIGAR forms
Only change E - I & O - U