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The present perfect tense:-
Indicates an action took place in the past, associated with the present idea of Now,eg:-
Got a job on 11th April,2014
but (have been fired ever)-----present perfect
at (end of May).
For an action just concluded when the resulting state is still present,eg:-
Up to now I'm looking for a job.
Since then I'm looking for a job.
The present perfect continuous tense:-
It is used to express the duration of an action up to the present.The tense suggests that the action is still continuing at the moment of speaking;and might continue into the future,eg:-
I have been looking for a job for 2 months (and am still looking) up to 11th June(=since 6-day duration posting),
This tense, and the other Perfect Continuous Tenses, are particularly associated with the words for and since which I've constructed illustrating the use of the Present Perfect Continuous according to your posting.