Deber Examples, Sentences & Quiz in Spanish

deber — to have to — is one of the verbs you will use every day in Spanish. Deber means must and should: deber + infinitive is an obligation (debo estudiar), while deber de + infinitive expresses probability (debe de estar enfermo). It is regular, but learners often confuse it with tener que, which is the stronger, more everyday way to say have to. On this page you will find deber in real sentences, grouped by meaning and tense, two short texts that show it in context, the mistakes learners actually make with it, and a ten-question quiz with explained answers. Start with the examples, say them aloud, and then test yourself.

Example sentences with deber

In the present tense

  • “Yo debo estudiar para el examen.” — “I must study for the exam.”
  • “Ella debe llegar antes de las ocho.” — “She must arrive before eight.”
  • “Nosotros debemos entregar el trabajo hoy.” — “We must hand in the work today.”
  • “Ellos deben respetar las normas.” — “They must respect the rules.”
  • “¿Tú debes hacer los deberes?” — “Must you do your homework?”
  • “Vosotros debéis escuchar al profesor.” — “You must listen to the teacher.”

In the preterite

  • “Ayer yo debí quedarme en casa.” — “Yesterday I had to stay at home.”
  • “Ella debió salir antes por la lluvia.” — “She had to leave early because of the rain.”
  • “Nosotros debimos cancelar el viaje.” — “We had to cancel the trip.”
  • “Ellos debieron pagar una multa.” — “They had to pay a fine.”
  • “¿Tú debiste trabajar el domingo?” — “Did you have to work on Sunday?”
  • “El médico debió operarse de urgencia.” — “The doctor had to operate urgently.”

In other tenses

The same verb in the imperfect, the future, the conditional and the present perfect — the four tenses that complete the picture. All forms come from the verified tables.

  • “De niño, yo debía estudiar en casa.” — “As a child, I used to have to study at home.”
  • “Mañana, yo deberé estudiar en casa.” — “Tomorrow, I will have to study at home.”
  • “Si pudiera, yo debería estudiar en casa.” — “If I could, I would have to study at home.”
  • “Yo he debido estudiar en casa.” — “I have had to study at home.”

Deber in context

Cada día, yo debo estudiar en casa. Mi amigo también debe estudiar en casa cuando tiene tiempo. Después, yo debo estudiar de nuevo por la tarde. Es una parte normal de mi rutina, y por eso el presente de deber es la primera forma que conviene aprender.

Ayer, yo debí estudiar en casa. Mi amigo debió estudiar en casa también, y por la noche yo debí estudiar otra vez. Fue un día normal, pero es justo en días así cuando el pretérito de deber aparece una y otra vez: una acción terminada, un momento concreto, y la historia sigue.

Common mistakes with deber

Mistake 1

Wrong: Yo debo de estudiar — wrong use of de.

Right: Yo debo estudiar.

Obligation is deber + infinitive; deber de + infinitive means probably.

Mistake 2

Wrong: Yo deber estudiar — using the infinitive.

Right: Yo debo estudiar.

Deber conjugates like any verb: debo, debes, debe — never the bare infinitive.

Quiz: deber in everyday use

Ten questions on deber across the tenses. Answers with explanations follow each question.

1. What is the yo form of deber in the present tense?

  • A) debo
  • B) debes
  • C) debe
  • D) debemos

Answer: A — The yo form in the present tense is debo.

2. What is the él/ella/Ud. form of deber in the present tense?

  • A) debo
  • B) debes
  • C) debemos
  • D) debe

Answer: D — The él/ella/Ud. form in the present tense is debe.

3. What is the yo form of deber in the preterite?

  • A) debió
  • B) debimos
  • C) debí
  • D) debiste

Answer: C — The yo form in the preterite is debí.

4. What is the ellos/ellas/Uds. form of deber in the preterite?

  • A) debió
  • B) debieron
  • C) debí
  • D) debiste

Answer: B — The ellos/ellas/Uds. form in the preterite is debieron.

5. What is the yo form of deber in the imperfect?

  • A) debía
  • B) debías
  • C) debía
  • D) debíamos

Answer: A — The yo form in the imperfect is debía.

6. What is the tú form of deber in the future?

  • A) deberé
  • B) deberá
  • C) deberemos
  • D) deberás

Answer: D — The tú form in the future is deberás.

7. What is the él/ella/Ud. form of deber in the conditional?

  • A) deberías
  • B) deberíamos
  • C) debería
  • D) debería

Answer: C — The él/ella/Ud. form in the conditional is debería.

8. What is the nosotros/as form of deber in the present perfect?

  • A) ha debido
  • B) hemos debido
  • C) he debido
  • D) has debido

Answer: B — The nosotros/as form in the present perfect is hemos debido.

9. Fill in the blank: “Yo ___ estudiar para el examen.” (I must study for the exam.)

  • A) debo
  • B) debes
  • C) debe
  • D) debemos

Answer: A — The sentence needs debo.

10. Which sentence is correct?

  • A) Yo debo estudiar.
  • B) Yo debo de estudiar — wrong use of de.

Answer: A — Obligation is deber + infinitive; deber de + infinitive means probably.

Frequently asked questions

What does deber mean?

deber means “to have to” in English. Deber means must and should: deber + infinitive is an obligation (debo estudiar), while deber de + infinitive expresses probability (debe de estar enfermo). It is regular, but learners often confuse it with tener que, which is the stronger, more everyday way to say have to.

Is deber regular?

Yes. deber is a regular -er verb, so its forms follow the standard endings in every tense. That makes it a good verb to learn early — once you know the endings, you know the verb.

When do I use deber in the past — preterite or imperfect?

Use the preterite — debí, debiste, debió — for a finished action at a specific moment, and the imperfect — debía, debías, debía — for what was happening, what used to happen, or the background. The same rule applies to deber as to every Spanish verb; the tense changes the meaning, not the verb.

How can I practise deber?

Start with the examples above, say them aloud, then take the quiz on this page. For more practice, use the Spanish Verb Quiz and the Deber Conjugator, and read the full conjugation page for deber to see the verb in every tense.

Say it yourself

Reading is not enough — say the verb aloud before you move on. Use the forms from the tables on this page and answer these three prompts as full sentences. First, say a sentence about yourself in the present tense: “Yo debo…”. Second, say a sentence about yesterday in the preterite: “Ayer yo debí…”. Third, say a sentence about tomorrow in the future: “Mañana yo deberé…”. If you can answer all three without looking at the tables, the forms are starting to stick. If you hesitate, go back to the examples above, read them aloud twice, and try again. Speaking the forms is what turns a table you have seen into a verb you can use.

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