Verbs simple aspect Continuous(progressive) aspect Perfect and Perfect Continuous aspect

The perfect aspect
The use of the perfect aspect indicates that the event took place before the time being referred to or that it covered a period of time up to the time being referre to. It also shows that this event has some relevance to the time being referred « John’s left, (present perfect)
John left before the present time.
He is not here now.
John had left when we got there, (past perfect)
John left before we got there.
He was not there when we got there.
John will have left when we get there, (future perfect)
John will leave before we get there.
He will not be there when we get there.
The infinitive can also have a perfect aspect:
He is sure to be there, (infinitive with to)
He is sure to have been there, (perfect infinitive with to)
(*= It is certain that he has been/was there.)
Modals can be followed by the infinitive or the perfect infinitive: