第2个回答 2013-12-21
THE INFINITIVE
OTHER FORMS
The infinitive can have the following forms:
The perfect infinitive
The continuous infinitive
The perfect continuous infinitive
The passive infinitive
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.
Examples:
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
Examples:
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
Examples:
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
Examples:
I am expecting to be given a pay-rise next month.
These doors should be shut.
This window ought to be opened.