In English, the infinitive is best thought of as the verb with 'to' preceding it. Infinitives serve as the base for conjugation and mirror the structure of their respective tenses. This is best illustrated with an example:

Simple Infinitive:
to + verb
to think
to manage

Perfect Infinitive:
to + have + past participle
to have thought
to have managed

Continuous Infinitive:
to + be + present participle
to be thinking
to be managing

Perfect Continuous Infinitive:
to + have + been + present participle
to have been thinking
to have been managing

There is also a passive infinitive, when the subject serves as the direct object
to + be + past participle
to be thought [of]
to be managed

Passive Perfect Infinitive:
to + have + been + past participle
to have been thought [of]
to have been managed

Ben

Thanks. Are they, complex infinitives, used only in passive forms of sentences that have subordinate clauses with sub conjunction that?

Ex: It is said that he went to the ceremony.

He is said to have gone to the ceremony.

Regards
Chinna

Chinn_asama wrote:Thanks. Are they, complex infinitives, used only in passive forms of sentences that have subordinate clauses with sub conjunction that?

Ex: It is said that he went to the ceremony.

He is said to have gone to the ceremony.

Regards
Chinna

The primary distinction is that the PRESENT infinitives serve to express CONTEMPORANEOUS action, while the PERFECT infinitives serve to express PRIOR action.
Check my posts here:

https://www.beatthegmat.com/past-perfect ... 04186.html
https://www.beatthegmat.com/easy-to-fall-for-t82394.html