Perfect Infinitive with Modals: Could Have, Would Have,…

 

Perfect Infinitive! Learn Perfect Infinitive with Modal Verbs in English with grammar rules, example sentences, video and ESL picture.

The structure “have + past participle” is called a perfect infinitive.

Perfect infinitive with modal verbs in English: must have, can’t have, should have, shouldn’t have, needn’t have, ought to have, may have, might have, could have, would have.

Perfect Infinitives

Must Have + Past Participle

Usage:

Express a deduction about something that has happened. We feel quite sure about it.

Examples:

I didn’t hear her voice . She must have gone out.

I cannot find my watch; I must have lost it.

Can’t Have + Past Participle

Usage:

Describe a deduction about something that didn’t happen in the past based on present evidence.

Examples:

He can’t have fallen in love with her. She’s married.

This can’t have been an economically sensible decision.

Should Have + Past Participle

Usage:

Express the idea that something was desirable or needed but didn’t take place.

Examples:

She should have asked you before borrowing your pen.

We should have had a proper discussion before voting.

Shouldn’t Have + Past Participle

Usage:

Something took place but it wasn’t desirable.

Example:

She shouldn’t have taken the matter too seriously.

Needn’t Have + Past Participle

Usage:

Express that something was done but it wasn’t necessary. The person who did it thought it was necessary.

Examples:

He needn’t have been so careful.

I needn’t have knocked at the door since, in this way, I awoke the baby. (but I knocked)

Ought to Have + Past Participle

Usage:

Express an unfulfilled duty or obligation.

Example:

I ought to have come earlier. I deeply regret.

May Have + Past Participle

Usage:

Express the possibility that an action took place in the past.

Example:

Alert readers may have noticed the misprint in last week’s column.

Might Have + Past Participle

Usage:

Express a past possibility.

Example:

Our neighbors might have heard some noises when our car was stolen.

Could Have + Past Participle

Usage:

Express past reference about something that was not carried out.

Examples:

You could have done it. (You didn’t do it)

You could have told me I had a snotty nose!

Would Have + Past Participle

Usage:

Used in the Third Conditional.

Example:

I would have gone to university if my parents had had more money. (The speaker didn’t go to university.)

Perfect Infinitive with Modal Verbs | Picture