USAGE: Use the Present Perfect Tense when we would like to say that there's something happened in the past time and it's still going on in the present time and we don't know when it will stop.
KEY : Present Perfect Continuous Tense uses the auxilliary "Have" or "Has" and the third-verb (or past participle). Look at this illustration below!
Sandy : How long have you been staying in this city, Tom?
Tom : Well, I have been staying here since 1995.
Place "not" behind the auxilliary (or haven't / hasn't) without changing the other word structures, Like:
(+) Mila has been completing her assignment.
(-) Mila hasn't been completing her assignment.
Place the auxilliary in the beginning of the sentence when you want to make an interrogative sentence by using this tense, like:
(+) Budi has been writing the story for 3 hours.
(?) Has He been writing the story for 3 hours?
Answer: /Yes, he has/ or /no, he hasn't/ or /no, he hasn't yet/ or /not yet!/
or, you can use the question word phrase, like /how long/.
(?Q) How long has he been writing the story?
It is possible for us to answer the question in this tense by using Present Continuous Tense.
Dina : What do you do, Ben?
Ben : I'm a personnel manager.
Dina : How long have you been working here?
Ben : I'm working here about three months
or, you can say a short answer, Like:
Ben : It's about three months.