perfect infinitive

Meanings

1. 1nouncountable

   A verb form made with 'to have' and a past participle, used to show that an action happened before another time or action.

   Grammar: Countable: you can say 'a perfect infinitive' or 'perfect infinitives'. It is a grammatical term, not a verb tense on its own.

   Patterns

   • the perfect infinitive of a verb
   • use a perfect infinitive after 'seem'
   • form the perfect infinitive with 'to have' + past participle

   In 'She seems to have forgotten her keys', 'to have forgotten' is a perfect infinitive.

   The perfect infinitive often follows 'appear', 'seem', or 'be believed'.

   To talk about an earlier action, use the perfect infinitive: 'He is thought to have left the country'.

2. 2nouncountable

   This structure used after 'would like', 'would prefer', etc., to express a wish about the past that did not happen.

   Grammar: Usually singular in this pattern: 'I would like to have seen it.'

   Patterns

   • would like to have done something
   • would prefer to have done something

   I would like to have studied music, but I chose science instead.

   She would have preferred to have taken the earlier train.

Word forms

Common combinations

seem to have done something

The children seem to have enjoyed the party.

be believed to have done something

The company is believed to have lost millions.

would like to have done something

I would like to have met your grandmother.

appear to have done something

He appears to have made a mistake.

Word family

infinitive noun

The base form of a verb, often with 'to', e.g. 'to go'.

present infinitive noun

The simple infinitive form, e.g. 'to eat', referring to the same time as the main verb.

Commonly confused: perfect infinitive or past participle?

Practice

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Write a sentence using “perfect infinitive”, then check it and compare it with the examples above.

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