Conjugate stem changers in the preterite tense

Essential grammar #70

Stem changing infinitives

Stem changing infinitives are named for what they do– change in the stem.

You are going to make some alteration of the stem before adding the verb endings.

You will use the preterite endings you already know.

The hardest part of stem changers is knowing which ones change and which ones don’t.

Two Rules for identifying Preterite Stem-Changers:

1. The infinitive must be a stem-changer in the present tense.

2. The infinitive must end in –ir.

Stem changers

There are 2 different ways a stem changing infinitive can change (2 categories).

-The first is ou.

-This includes present tense oue.

dormir = to sleep

This is a stem changer in the preterite.First separate the stem from the infinitive ending.Dorm- is the stem.Make the stem change ouNew stem durm-Put into box– In the present tense, it looks like a boot. In the preterite tense, it looks like a sandal.Only the 3rd and 6th box make stem changes.

dormir = to sleep

dormí

dormí

dormiste

dormí

dormiste

durmió

dormí dormimos

dormiste

durmió

dormí dormimos

dormiste dormisteis

durmió

dormí dormimos

dormiste dormisteis

durmió durmieron

Stem changers

The second category is ei.

(This includes present tense changes eie and ei).

preferir = to prefer is a stem changer.

It is the same steps as dormir.

*When there is more than one vowel that could possible make the change, choose the vowel closest to the verb ending.

Preferir = to prefer

First separate the stem from the infinitive ending.

prefer- is the stem.

Make the stem change ei

New stem prefir-

Put into box– remember it will look like a sandal in the preterite. It will only change in the 3rd and 6th boxes.

preferir = to prefer

preferí

preferí

preferiste

preferí

preferiste

prefirió

preferí preferimos

preferiste

prefirió

preferí preferimos

preferiste preferisteis

prefirió

preferí preferimos

preferiste preferisteis

prefirió prefirieron

Stem changers

.

servir = to serve is a stem changer.

It is the same steps as preferir.

servir = to serve

First separate the stem from the infinitive ending.

serv- is the stem.

Make the stem change ei

New stem sirv-

Put into box– remember it will look like a sandal. In the preterite, only the 3rd and 6th boxes show change.

servir = to serve

serví

serví

serviste

serví

serviste

sirvió

serví servimos

serviste

sirvió

serví servimos

serviste servisteis

sirvió

serví servimos

serviste servisteis

sirvió sirvieron

Ellos pedir

Ella repetir

Nosotros sentir

Usted entender

Tú dormir

Ella seguir

Ellos pidieron

Ella repitió

Nosotros sentimos

Usted entendió

Tú dormiste

Ella siguió