casadoalan | gramática inglesa

Past modal verbs

could have, might have, must have and can't have.

Read this dialogue. Four people have arranged to meet in front of a cinema. Laura has not arrived yet.

- I wonder what's happened to Laura.
- She could have had a late meeting at the office, I suppose.
- I've just rung Laura at home and her line's engaged. She must have forgotten about this evening.
- She can't have forgotten. I saw her writing it in her diary.
- Come on, let's go in. I don't want to miss the beginning.

I
He
She
It
We
You
They

May/might/can't have are used when the speaker is speculating about the past:

She could have had a late meeting at theoffice (that's why she hasn't arrived yet).
She may/might/ have got the wrong day.
These are all similar in meaning.

Must have/can't have are used when the speaker is drawing a conclusion about something that happened in the past:

She must have forgotten about this evening.
She can't have forgotten.

Note

These structures also have a continuous form:

She might/must/can't have been waiting all morning.

exercises

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