‐ar or ‐er Verbs in the Preterit

No ‐ar or ‐er verbs undergo a stem change in the preterit. Remember that ‐ar and ‐er verbs that undergo a stem change in the present tense do not undergo a stem change in the preterit. The verb pensar (to think) is a good example of this. Look carefully at the forms in Table and notice the lack of stem change in the preterit.