demostrar Imperfect Subjunctive Conjugation
demostrar — to prove
The imperfect subjunctive is regular: demostrara, demostraras, demostrara, demostráramos, demostrarais, demostraran.
demostrar Imperfect Subjunctive Forms
When to Use the Imperfect Subjunctive
Use this for 'if' clauses (e.g., 'If I proved...') or after past-tense verbs of emotion or doubt.
Notes on demostrar in the Imperfect Subjunctive
This tense is based on the 3rd person plural preterite (demostraron). It has no stem change.
Example Sentences
Si yo demostrara eso, todos me creerían.
If I proved that, everyone would believe me.
yo
Me gustaría que ellos demostraran más interés.
I would like them to show more interest.
ellos/ellas/ustedes
Common Mistakes
Mistake: demuestrara
Correct: demostrara
Why: Learners often mistakenly apply the present tense stem change to the subjunctive past.
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Related Tenses
Present
yo: demuestro
Demostrar is an o > ue stem-changing verb in all forms except nosotros and vosotros.
Preterite
yo: demostré
Demostrar is regular in the preterite: demostré, demostraste, demostró, demostramos, demostrasteis, demostraron.
Imperfect
yo: demostraba
Demostrar is regular in the imperfect: demostraba, demostrabas, demostraba, demostrábamos, demostrabais, demostraban.
Future
yo: demostraré
The future of demostrar is regular: demostraré, demostrarás, demostrará, demostraremos, demostraréis, demostrarán.
Conditional
yo: demostraría
The conditional of demostrar is regular: demostraría, demostrarías, demostraría, demostraríamos, demostraríais, demostrarían.
Present Subjunctive
yo: demuestre
Demostrar has a stem change (o > ue) in the subjunctive, except for nosotros and vosotros.
Affirmative Imperative
yo: demuestra
The imperative uses 'demuestra' (tú) and 'demuestre' (usted), following the o > ue stem change.
Negative Imperative
yo: no demuestres
The negative imperative uses the present subjunctive: no demuestres, no demuestre, no demostremos, no demostréis, no demuestren.