prevenir
to prevent, to forestall, to preempt
Más vale prevenir que curar.
Better safe than sorry.
prevenir present indicative
Habitual and ongoing actions in the present.
prevenir present continuous
Action in progress right now. Periphrastic: estar (present) + gerund.
prevenir preterite
Completed actions at a specific moment in the past.
prevenir imperfect
Habitual past actions, descriptions, background.
prevenir present perfect
Completed actions with present relevance. Auxiliary haber + participle.
prevenir future
Actions yet to happen.
prevenir informal future
Near-future plans. Periphrastic: ir (present) + a + infinitive.
prevenir future perfect
Action that will have been completed by a future moment. Auxiliary haber (future) + participle.
prevenir conditional
Hypothetical or polite would-actions.
prevenir conditional perfect
Hypothetical past: would have done. Auxiliary haber (conditional) + participle.
prevenir pluperfect
An action completed before another past action.
prevenir subjunctive present
Desires, doubts, and hypotheticals in the present.
prevenir subjunctive imperfect
Past subjunctive: desires, doubts, hypotheticals in the past.
prevenir subjunctive present perfect
Completed actions in subjunctive contexts.
prevenir subjunctive pluperfect
Past-perfect actions in subjunctive contexts.
prevenir imperative (affirmative)
Affirmative commands.
prevenir imperative (negative)
Negative commands: borrows subjunctive present.