• What this is about (de qué se trata)
• Must have (debió de haber)
• Might have / may have (podría haber / puede que haya)
• Could have (podría haber)
• Should have / shouldn't have (debería haber / no debería haber)
• Can't have (no puede haber)
• Summary table (cuadro resumen)

What this is about (de qué se trata)

In Book 2, we learned modal verbs for the present: can, must, should, may, might. Now we'll learn how to use them to talk about the past. We combine a modal verb with have + past participle.

🔹 En el Libro 2 aprendimos los verbos modales para el presente: can, must, should, may, might. Ahora aprenderemos a usarlos para hablar del pasado. Combinamos un verbo modal con have + participio pasado.

Must have (debió de haber)

Must have + past participle is used when we are almost certain something happened:

🔹 Must have + participio pasado se usa cuando estamos casi seguros de que algo ocurrió:

She must have forgotten. (Ella debió de haberse olvidado). => I'm almost sure she forgot.

He's not here. He must have left early. (No está aquí. Debe de haberse ido pronto).

They must have been very tired after the trip. (Debieron de estar muy cansados después del viaje).

Might have / may have (podría haber / puede que haya)

Might have or may have + past participle is used when something is possible but we're not sure:

🔹 Might have o may have + participio pasado se usa cuando algo es posible pero no estamos seguros:

He might have gone home. (Puede que se haya ido a casa). => It's possible.

She may have missed the bus. (Puede que haya perdido el autobús).

They might not have received the email. (Puede que no hayan recibido el correo).

Could have (podría haber)

Could have + past participle is used for past possibilities - things that were possible but didn't happen:

🔹 Could have + participio pasado se usa para posibilidades pasadas - cosas que eran posibles pero no ocurrieron:

We could have won the game. (Podríamos haber ganado el partido). => But we didn't.

You could have told me! (¡Podrías habérmelo dicho!)

She could have become a doctor. (Ella podría haber sido médica). => But she chose something else.

Should have / shouldn't have (debería haber / no debería haber)

Should have + past participle is used for regret or criticism about the past - things that were the right thing to do but didn't happen (or vice versa):

🔹 Should have + participio pasado se usa para arrepentimiento o crítica sobre el pasado - cosas que eran lo correcto pero no se hicieron (o viceversa):

You should have called me. (Deberías haberme llamado). => But you didn't.

I shouldn't have eaten so much. (No debería haber comido tanto). => But I did.

We should have left earlier. (Deberíamos haber salido antes).

She shouldn't have said that. (Ella no debería haber dicho eso).

Can't have (no puede haber)

Can't have + past participle is used when we are almost certain something did NOT happen:

🔹 Can't have + participio pasado se usa cuando estamos casi seguros de que algo NO ocurrió:

She can't have said that. She's too polite. (No puede haber dicho eso. Es demasiado educada).

He can't have finished already. He only started ten minutes ago. (No puede haber terminado ya. Empezó hace solo diez minutos).

Summary table (cuadro resumen)

must have + pp => almost certain it happened (deduction)

might have / may have + pp => possible but not sure

could have + pp => was possible but didn't happen

should have / shouldn't have + pp => regret / criticism

can't have + pp => almost certain it didn't happen