The infinitive can have the following forms:
NOTE: as with the present infinitive, there are situations where the to is omitted, e.g. after most modal auxiliaries.
|The perfect infinitive:|
to have + past participle, e.g. to have broken, to have seen, to have saved.
This form is most commonly found in Type 3 conditional sentences, using the conditional perfect, e.g. If I had known you were coming I would have baked a cake.
- Someone must have broken the window and climbed in.
- I would like to have seen the Taj Mahal when I was in India.
- He pretended to have seen the film.
- If I’d seen the ball I would have caught it.
|The continuous infinitive:|
to be + present participle, e.g.to be swimming, to be joking, to be waiting
- I’d really like to be swimming in a nice cool pool right now.
- You must be joking!
- I happened to be waiting for the bus when the accident happened.
|The perfect continuous infinitive:|
to have been + present participle
- to have been crying
- to have been waiting
- to have been painting
- The woman seemed to have been crying.
- You must have been waiting for hours!
- He pretended to have been painting all day.
|The passive infinitive:|
to be + past participle, e.g. to be given, to be shut, to be opened
- I am expecting to be given a pay-rise next month.
- These doors should be shut.
- This window ought to be opened.