15.1 Stem-Changers
In the preterite, some of the most common verbs take on completely new stems. These aren't small tweaks — the stems change so dramatically that the verbs can look and sound quite different from their infinitives. The good news is that these are high-frequency verbs, so you'll encounter them constantly, and VerbMaster has plenty of practice to help you master them.
The process is the same as always: break the infinitive in half and swap the stem for a new one. For example, hacer (to do) becomes HIC‑, tener (to have) becomes TUV‑, and decir (to say) becomes DIJ‑. Then you add a special set of preterite endings (shown after the charts below).
Let's see these in action:
Here are the endings used by all of these stem-changing preterite verbs. Notice that the yo and él/ella/usted forms have no written accents — unlike regular preterite endings:
| yo | -e |
| tú | -iste |
| él/ella/Ud. | -o |
| nosotros/as | -imos |
| vosotros/as | -isteis |
| ellos/ellas/Uds. | -ieron |
15.2 More Stem-Change Verbs
Here are more verbs that follow this same pattern — each one swaps its stem in the preterite and uses the endings from Section 15.1:
Stem-Changing Verbs in the Preterite
| estar (to be) → estuv- | haber (to have) → hub- |
| poder (to be able to) → pud- | querer (to want) → quis- |
| saber (to know) → sup- | poner (to put, to set) → pus- |
| venir (to come) → vin- | mantener (to maintain) → mantuv-* |
| obtener (to obtain) → obtuv-* | suponer (to suppose) → supus-* |
| traer (to bring) → traj- | andar (to walk) → anduv- |
* Notice that some of these verbs are prefixed forms of other verbs on the list. A prefixed verb is just a root verb with extra letters stuck on the front — and those extra letters never change. The root verb does all the conjugating:
- man + tener = mantener → man + tuv‑ = mantuv‑
- ob + tener = obtener → ob + tuv‑ = obtuv‑
- su + poner = suponer → su + pus‑ = supus‑
Learn one root verb's pattern and you get its whole family for free!
Practice Time!
Master these verb conjugations from Lesson 15