2.4 Perfective

Perfective aspect combines with present and past tense and progressive aspect to form the following verbal constructions:

present perfect: I have worked
past perfect: I had worked
present perfect progressive: I have been working
past perfect progressive: I had been working

Like the progressive, perfective aspect also occurs in combination with modal and auxiliary verbs:

I can have worked
I was going to have worked
I will have worked
I would have worked

The traditional name for the combination will + have + -ed participle is the future perfect (cf. 2-3).

The meaning of the present perfect and present perfect progressive, as opposed to the simple past, is described in 2.2. The past perfect and future perfect refer to events in the past or future which occur previous to some other event, e.g.:

I had corrected all the papers when he arrived.
I will have corrected all the papers when he arrives.

In both sentences the correcting of the papers occurs before his arrival, and the time reference can be described as past-in-the-past and past-in-the-future, respectively.