When we said there were only four irregular verbs in the preterite tense, we were not exactly honest with you.  There are a couple… dozen… more but you know all them quite well since they also are irregular in the present tense. The good thing here is that some of the irregular stem-changing verbs from the present become quite regular in the past. Let’s deal with all of them in turn.

Whether a stem-changing verb will or will not change its stem in the preterite tense depends on its final two letters.

Stem-Changing –AR and –ER Verbs

The verbs that end in -er and -ar do NOT change their stems in the preterite; they take regular preterite tense forms based on either the -ar or the -er conjugation pattern. Here’s a table that illustrates the mechanism:

Stem-Changing –IR Verbs

The stem-changing verbs that end in -ir still change their stems in the preterite. However, there are some differences:

1. the stem vowel only changes in the 3rd person singular and plural forms,
2. it does not change to a letter combination (e->ie or o->ue), but to a single vowel – the first from the said combination of the present tense forms.

This table will probably tell it better than any explanation would:

And now, it’s time to put your immediate memory to a short test!