Usage Examples
[Present Indicative] Debo estudiar para el examen. → I must study for the exam.
[Present Perfect] He debido de entender mal. → I must have misunderstood.
[Imperfect Indicative] Debía mucho dinero al banco. → I owed a lot of money to the bank.
[Pluperfect Indicative] Había debido favores antes. → I had owed favors before.
[Preterite] Debí haberte escuchado. → I should have listened to you.
[Preterite Anterior] Cuando hubo debido dinero, se preocupó. → When he had owed money, he got worried.
[Future] Deberé pagar la factura pronto. → I will have to pay the bill soon.
[Future Perfect] Habré debido de perder las llaves. → I must have lost the keys.
[Conditional] Deberías descansar más. → You should rest more.
[Conditional Perfect] Habría debido llamar antes. → I should have called earlier.