Present tense: O → UE stem-changing verbs
In selected verbs, a stressed o in the stem changes to ue in the present tense. The personal ending still comes from the verb's -AR, -ER or -IR family.
The change appears with yo, tú, él, ella, usted, ellos, ellas and ustedes, but not with nosotros, nosotras, vosotros or vosotras.
1. The O → UE boot pattern
Change the stressed o to ue in the boot forms. Keep o with nosotros and vosotros, and preserve the person ending required by the infinitive family.
2. The stem changes; the ending still agrees
The stem change never replaces the person ending. Encontrar keeps -AR endings, volver keeps -ER endings and dormir keeps -IR endings.
3. Useful everyday structures
Meaning and the following structure are part of using the verb correctly.
4. Important meaning contrasts
Encontrar means to find; buscar means to look for. Volver means to return, while devolver means to return an object. Sonar means to sound or ring; soñar means to dream. Probar can mean to taste or try, while intentar means to attempt an action.
5. Other patterns are separate
Do not confuse O → UE with E → IE, E → I or U → UE. Pensar becomes pienso, pedir becomes pido, poder becomes puedo and jugar becomes juego. Many verbs containing o, such as tomar, comprar and cocinar, remain regular.
6. Subjects, negatives and questions
Names and groups determine the person even when no pronoun appears. Put no before the conjugated verb and form questions directly with that verb.
6. Common mistakes
The stressed o changes to ue.
Nosotros stays outside the boot.
Devolver is an -ER verb and uses -éis.
After poder, the second verb remains an infinitive.
Soñar uses con.
7. A reliable method
- Confirm that the verb belongs to the O → UE group.
- Identify the subject.
- Change o to ue only in a boot person.
- Use the ending required by the -AR, -ER or -IR family.
- Check the verb's meaning and required structure.