ser to beFuture Perfect Subjunctive / Futuro Perfecto de Subjuntivoyohubiere sidotúhubieres sidoél / Ud.hubiere sidonosotroshubiéremos sidovosotroshubiereis sidoellos / Uds.hubieren sido
Other Tenses / Moods of Ser Simple Tenses Present Tense Imperfect Tense Preterite (Past Tense) Future Tense Conditional Tense Subjunctive Tense Imperfect Subjunctive Future Subjunctive Imperative (Command) Past Participle & Gerund Compound Tenses Present Perfect Past Perfect Past Anterior (Preterite Perfect) Future Perfect Conditional Perfect Present Perfect Subjunctive Pluperfect Subjunctive Future Perfect Subjunctive