interferir Imperfect Subjunctive Conjugation
interferir — to interfere
The imperfect subjunctive uses the 'interfir-' stem for all forms (interfiriera, interfirieras).
interferir Imperfect Subjunctive Forms
When to Use the Imperfect Subjunctive
Use in 'if' clauses (hypotheticals) or when the main verb is in the past and expresses a wish or doubt.
Notes on interferir in the Imperfect Subjunctive
This tense is derived from the third-person plural preterite (interfirieron). Therefore, the 'i' change applies to all forms.
Example Sentences
Si yo interfiriera, las cosas serían peores.
If I were to interfere, things would be worse.
yo
Dudaba que ellos interfirieran en el asunto.
I doubted that they would interfere in the matter.
ellos/ellas/ustedes
Common Mistakes
Mistake: interferiera
Correct: interfiriera
Why: You must use the preterite-style stem (with the 'i') for the imperfect subjunctive.
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Related Tenses
Present
yo: interfiero
Interferir is a stem-changing verb in the present tense (e -> ie), except for nosotros and vosotros.
Preterite
yo: interferí
Interferir has a third-person stem change (e -> i) in the preterite: interfirió and interfirieron.
Imperfect
yo: interfería
Interferir is completely regular in the imperfect: interfería, interferías, interfería...
Future
yo: interferiré
Interferir is regular in the future; simply add endings to the infinitive.
Conditional
yo: interferiría
The conditional of interferir is regular: interferiría, interferirías, etc.
Present Subjunctive
yo: interfiera
Interferir has a stem change (ie) and a special nosotros/vosotros change (i) in the subjunctive.
Affirmative Imperative
yo: interfiere
Use 'interfiere' to tell someone to step in, or 'interfiera' for formal requests.
Negative Imperative
yo: no interfieras
The negative imperative always uses the present subjunctive forms: no interfieras, no interfiera.