
prevenir Imperfect Subjunctive Conjugation
prevenir — to prevent
Based on the preterite stem: previniera, previnieras, previniera.
prevenir Imperfect Subjunctive Forms
When to Use the Imperfect Subjunctive
Use for hypothetical 'if' situations (If I prevented...) or after past-tense verbs expressing influence or emotion.
Notes on prevenir in the Imperfect Subjunctive
This tense is built from the third-person plural preterite (previnieron), using the 'previn-' stem.
Example Sentences
Si yo previniera el problema, no estaríamos así.
If I prevented the problem, we wouldn't be like this.
yo
Fue una pena que no previnieran el ruido.
It was a shame they didn't prevent the noise.
ellos/ellas/ustedes
Te pedí que previnieras a tus amigos.
I asked you to warn/prevent your friends.
tú
Common Mistakes
Mistake: preveniera
Correct: previniera
Why: The imperfect subjunctive must use the same 'i' stem as the preterite (previn-).
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Related Tenses
Present
yo: prevengo
Prevenir is a stem-changing verb (e > ie) with a special 'yo' form: prevengo.
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.
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.