Forms of the Infinitive

There are several forms of the Infinitive in English: Indefinite, Continuous, Perfect and Perfect Continuous which are used to show both the simultaneousness or the priority of the action of the Infinitive to the main verb and the form's aspect. Some of them have Passive forms:

	Active	Passive
Indefinite	to speak	to be spoken
Continuous	to be speaking	–
Perfect	to have spoken	to have been spoken
Perfect Continuous	to have been speaking	–

The Indefinite Infinitive expresses an action simultaneous with that of the finite verb, so it may refer to the present, past or future:

I'm glad to meet you.

I was glad to see her.

I'll be glad to come.

It's glorious to love and to be loved.

There is no time to lose. = There is no time to be lost.

The Continuous Infinitive expresses an action simultaneous with that of the finite verb, but this is an action in progress:

They happened to be standing near a small restaurant.

The Perfect Infinitive expresses an action

1) prior to that of the finite verb:

I'm glad to have seen you.

2) a prior action that was not carried out:

I meant to have gone there. (But I didn't go there).

The Perfect Continuous Infinitive expresses the action which lasted a certain time before the action of the finite verb

She seemed to have been eating nothing for ten days.