Quick answer
deber · debo, debes, debe, debemos, debéis, deben
must, to owe. Fully regular, so the endings carry over to every other -er verb.
Conjugation
| Person | Present | Preterite | Imperfect | Future |
|---|---|---|---|---|
| yo | debo | debí | debía | deberé |
| tú | debes | debiste | debías | deberás |
| él / ella / usted | debe | debió | debía | deberá |
| nosotros | debemos | debimos | debíamos | deberemos |
| vosotros | debéis | debisteis | debíais | deberéis |
| ellos / ustedes | deben | debieron | debían | deberán |
Orange marks a form you cannot guess from the rules.
| Non-finite | Form |
|---|---|
| gerund | debiendo |
| past participle | debido |
| imperative (tú) | debe |
| subjunctive (yo) | deba |
Which form to learn first
debo. With an infinitive it is “I must”, with money it is “I owe”.
Where you will actually use it
Debo irme.I must go.
Debes descansar.You should rest.
Me debes veinte euros.You owe me twenty euros.
Deberías llamarla.You ought to call her — the conditional softens it.
No debes fumar aquí.You must not smoke here.
Debe de estar cansado.He must be tired — deber de for a guess.
Typical mistakes
Debo a irme.
Debo irme.
deber takes a bare infinitive, with no preposition.
Debo que trabajar.
Debo trabajar.
No que either — that belongs with tener que.
Debe ser en casa (guessing).
Debe de estar en casa.
deber + infinitive is obligation; deber de + infinitive is a guess.
Check yourself
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