What is the difference between present perfect tense and present perfect progressive tense?

Answer 1

Formally, the present perfect tense is formed by combining a suitable present indicative form of "to have" (has or have, depending on number) with a past participle of some substantive verb, while a present perfect progressive tense combines a present indicative form of "to have" with "been" (the past participle of "to be") and a present particle of a substantive verb. Substantively, a present perfect tense shows that the action of a substantive verb has been completed at the time the tense is written, while a present perfect progressive tense indicates that the action of the substantive verb is still in process. For example, "The temperature has changed substantially" implies that the change is at least temporarily complete, while "The temperature has been changing substantially" implies that some change has already occurred and that further change is likely.