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Verbos con cambio radical
Stem-Changing Verbs:

Contesta, por favor:

Conjugating stem-changing verbs is almost as simple as doing regular verbs, except the stem of these verbs has a change.  Just so you know, the "stem" is that part of the verb that is left after you drop the infinitive ending (AR, ER or IR).  Another important note is that anytime a stem has a change, it is always in its (the stem's) last syllable.

I cannot answer why some verbs are stem-changing and others not, but you do need to know the common ones that are.  But how do you know if a verb is stem-changing or not?  There are a number of words you already know that are stem-changing, and hopefully there will be a lot more after studying this lesson.  Also, a number of texts, glossaries and dictionaries label stem changes by showing the possible change in brackets , such as [ie] or [ue].  So let's look at how they are conjugated, then you can get some lists at

The endings of stem-changing verbs are the same as the regular present tense, so that part is easy.  The only thing you have to worry about is what the change may be.  You should also make a note that these changes never occur in the nosotros and vosotros forms in the present tense.

o to ue

Go to the page for o to ue changes.  Read the information and copy the list of common verbs into your notebook.  Choose ten of these verbs and for each of these write a sentence in the "YO" form and another in the "... (somebody) Y YO"(=nosotros, ¿verdad?) form.  Do the quiz and the oral activity, then take the test.

e to ie

Do as you did, exactly as above, at for this section of stem- changing verbs.

e to i

You know what to do at, ¿verdad?

There are some other changes that you should also be aware of besides these common ones.  So follow along and look at these.

e to í

reír (to laugh):  río, ríes, ríe, reímos, reís, ríen
sonreír (to smile): sonrío, sonríes, sonríe, sonreímos, sonreís, sonríen

i to í

This change occurs in some verbs that end in IAR:

enviar (to send): envío, envías, envía, enviamos, enviáis, envían

verbs like enviar: confiar [en] (to rely on, to confide in); espiar (to spy); fiarse [de] (to trust); guiar (to guide);  resfriarse (to catch a cold); variar (to vary)

u to ú
This change occurs in a few verbs endng in -uar.

actuar (to act): actúo, actúas, actúa, actuamos, actuáis, actúan

verbs like actuar: continuar (to continue); graduarse (to graduate)

u to uy

This change will occur in all verbs that end in uir, except for those that end in -guirWhy don't we include "-guir" verbs in this category?  Hypothesize, then check.

construir (to build, construct): construyo, construyes, construye, construimos, construís, construyen

Common verbs like construir:

concluir (to conclude); contribuir (to contribute); destruir (to destroy); distribuir (to distribute); huir (to flee, run away from); incluir (to include); sustituir (to substitute)

Since there are no specific activities for these verbs at, you should do the following for practice:

Contesta las preguntas siguientes con frases completas.

¿Cuándo ríes?
¿Sonríen mucho tus profesores?  Explica por qué.
¿Quién huye de la policía?
En la clase de español, ¿qué estudiante contribuye más?
¿Envías muchas cartas?  ¿A quién?
¿Quién guía tu grupo de amigos?
Conoces a alguien que destruye cosas con frecuencia?  Explica.
¿Qué amigos tuyos actúan? ¿Actúas?
¿Reís mucho tú y tus amigos?
¿Quién se gradúa este año?  ¿Te gradúas pronto?


In -guir verbs, the "u" serves only to keep the hard "g" sound.  Therefore, it is not "it's own letter", and cannot be treated like words in which it is.  Got it?