prevenir Present Conjugation
prevenir — to prevent
Prevenir is a stem-changing verb (e > ie) with a special 'yo' form: prevengo.
prevenir Present Forms
When to Use the Present
Use the present tense to discuss current habits, general warnings, or medical advice meant for the general public.
Notes on prevenir in the Present
This verb follows the pattern of 'venir'. It has a 'go' in the first person (prevengo) and a stem change (e > ie) in all other forms except nosotros and vosotros.
Example Sentences
Yo siempre prevengo los problemas antes de que ocurran.
I always prevent problems before they happen.
yo
Esta vacuna previene el contagio.
This vaccine prevents infection.
él/ella/usted
Nosotros prevenimos accidentes con estas reglas.
We prevent accidents with these rules.
nosotros
Common Mistakes
Mistake: yo preveno
Correct: yo prevengo
Why: Prevenir follows the irregular 'yo' form of venir.
Mistake: él prevene
Correct: él previene
Why: The stem changes from 'e' to 'ie' in the third person singular.
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Related Tenses
Preterite
yo: previne
Prevenir uses an irregular stem 'previn-' in the preterite: previne, previste, previno...
Imperfect
yo: prevenía
Prevenir is completely regular in the imperfect: prevenía, prevenías, prevenía...
Future
yo: prevendré
Prevenir uses the irregular stem 'prevendr-': prevendré, prevendrás, prevendrá.
Conditional
yo: prevendría
Prevenir uses the irregular stem 'prevendr-' plus -ía endings.
Present Subjunctive
yo: prevenga
The present subjunctive uses the 'preveng-' stem: prevenga, prevengas, prevenga.
Imperfect Subjunctive
yo: previniera
Based on the preterite stem: previniera, previnieras, previniera.
Affirmative Imperative
yo: prevén
The affirmative commands are: prevén (tú), prevenga (usted), prevengamos (nosotros).
Negative Imperative
yo: no prevengas
Negative commands use 'no' + present subjunctive: no prevengas, no prevenga.