Modern Spanish Grammar: A Practical Guide

(c) Obligation

 46.1 (p. 272)

Podríais/podíais/pudisteis habérselo explicado. (see 46.1)

You might have (= ought to have) explained it to him/her.

(d) Permission

 54.1 (p. 314); 70.1 (p. 390)

¿Puedo entrar? (see 54.1)

May I come in?

¿Puedo cerrar la puerta? (see 54.2)

May I close the door?

Puede usted quedarse aquí si desea. (see 70.1)

You can stay if you like.

(e) With imperative force

^68 (p. 381); 69.2 (p. 387)

¿Puedes subir un momento? (see 68 )

Can you come up for a moment?

¿Podrías poner esto allí? (see 68 )

Could you put this over there?

21.2Deber (de)

 48.1 (p. 282);^50 (p. 296)

Deber (de) is used to express:

(a) Supposition

NOTE Although strictly deber should be followed by de in this meaning, this rule is by no means always

observed.

Deben (de) ser más de las seis. (see 48.1, 50)

It must be past six o’clock.

Deben (de) haber regresado ya. (see 48.1, 50)

They must have returned already.

Debían (de) ser las seis cuando empezó a llover.

It must have been six o’clock when it started to rain.

José debió (de) terminarlo ayer.

José must have finished it yesterday.

In referring to the past, the choice between imperfect and preterite is determined by the

tense of the corresponding straightforward statement; thus

MODAL AUXILIARY VERBS AND EXPRESSIONS 21.2