PRESENT PERFECT CONTINUOUS TENSE
(I have been doing)

FORM have been or has been and present participle (I have been working, he has been writing)
   
USE

It is used for an action which began in the past and is still continuing at the moment of speaking, or has only just finished. The action may continue into the future.

   
EXAMPLES 1. I have been teaching this class for three years (and am still teaching it).
2. I have been waiting for an hour and he still has not come.
3. Mary has been going out with Mike for half a year. I am sorry I am late. Have you been waiting long?
4. Your hands are dirty. What have you been doing? I have been repairing my bike.
   

Difference between Present Perfect Simple and Continuous

They have repaired the roof.
They have been repairing the roof.
Completion -> Ergebnis
Progress -> Verlauf
The work is finished.

The work is not finished.