Learn Spanish in Simple way: Simple Past tense - How irregular verbs conjugation works.

Spanish verbs that undergo a spelling change in the preterite fall into two main groups, both of which we'll talk about in more depth below.

Group 1: -car, -gar, and -zar Verbs

The first-person singular (yo) endings of these verbs undergo the following changes:

Here is an example of the full preterite tense conjugation for each type of verb.

Subject	Bus-car Conjugation	Ju-gar Conjugation	Cru-zar Conjugation
yo	busqué	jugué	crucé
tú	buscaste	jugaste	cruzaste
él, ella, usted	buscó	jugó	cruzó
nosotros	buscamos	jugamos	cruzamos
vosotros	buscasteis	jugasteis	cruzasteis
ellos, ellas, ustedes	buscaron	jugaron	cruzaron

Here is a list of some common -car, -gar, and -zar verbs you're likely to hear.

The third person singular, third person plural, and second person formal singular endings of these verbs all undergo the same change.

Subject	Change	Example
Third person singular (él, ella)	i changes to y	leyó
Third person plural (ellos, ellas)	i changes to y	leyeron
Second person formal singular (usted)	i changes to y	leyó

Here is an example of the full preterite tense conjugation for each type of verb.

Subject	Roer Conjugation	Oír Conjugation	Concluir Conjugation
yo	roí	oí	concluí
tú	roíste	oíste	concluíste
él, ella, usted	royó	oyó	concluyó
nosotros	roímos	oímos	concluímos
vosotros	roísteis	oísteis	concluísteis
ellos, ellas, ustedes	royeron	oyeron	concluyeron

Here is a list of some common -caer, -eer, -oer, -oír, and -uír verbs you're likely to hear.