Do you remember the three groups of verbs that change their stem vowel when it’s stressed? They were presented in section 5.4 of the Español 1 book. If you don’t remember, you may want to review how these verbs work in the present tense before moving on with this chapter’s topic: stem-changers in the preterit tense.

Stem-changing -AR and -ER verbs in the preterit

-AR and -ER verbs that have a stem change in the present tense, don’t have a stem change in the preterit tense. For example:

• (devolver) Yo devolví los pantalones por ser muy grandes. (I returned the pants for being too big.)
• (volar) El billonario voló a España para comprar zapatos de cuero. (The billionaire flew to Spain to buy leather shoes.)

Stem-changing -IR verbs in the preterit

However, the -IR stem-changing verbs *do* have a change in the preterit: but it’s only in the third person (singular and plural), and -IR stem-changers will change their stem vowel to just the first letter of the stem-change they had in the present tense.

So, -IR verbs that changed from “e” to “ie” in the present will change just from “e” to “i” in the preterit. -IR verbs that changed from “o” to “ue” in the present will change just from “o” to “u” in the preterit. And -IR verbs that changed from “e” to “i” in the present will do just that in the preterit.

Conjugation of stem-changing -IR verbs in the preterit

Preferir (e-ie,i) to prefer	Dormir (o-ue, u) to sleep	Pedir (e-i,i) to request
preferí	dormí	pedí
preferiste	dormiste	pediste
prefirió	durmió	pidió
preferimos	dormimos	pedimos
preferisteis	dormisteis	pedisteis
prefirieron	durmieron	pidieron

• ¿Pediste unas prendas de ropa de Zara.com? (Did you order/request some clothing from Zara.com?)
• No, pero Luisa pidió mucha ropa de ese sitio. (No, but Luisa ordered lots of clothes from that site.)
• Ella se vistió de pies a cabeza en ropa de Zara.com. (She dressed from head to toe in clothes from Zara.com.)

The best way to learn these conjugations is to say them out loud until they sound right to you. Practice, and train your ear! Once you hear the endings and changes right in your head, you’ll be able to spell them right on the page.