Present Perfect Continuous : Form 

affirmative
I / You / We / They    have ('ve)
She/ He / It                  has ('s)                                      been reading

negative

I / You / We / They            have not (haven't / 've not)    been      working.

She / He / It                        has not (hasn't / 's not)

questions

                Have    I / You / We / They               been waiting ?
                Has       She / He / It                            been waiting ?          
What       Have        you                                             been doing ?
Where     Has          she                                            been saying  ?

short answers

Yes    I / you / we / they      have
           she / he / it                  has

No  I / you / we / they      haven't
         she / he / it                  has

Use present perfect continuous

• to talk about recent continuing activities.
What have you been doing lately?
I've been revising for my exams.
• to explain how recent continuing activities have caused the present situation.
My eyes ache. I've been reading all day.
• to talk about recent continuing activities which will probably continue in the future.
This diagram shows how the climate has been changing.
• with how long questions.
How long have you been studying French?
(this is a continuing process,and isn't finished)
• with time words lately, recently, all (day), every (morning), for, since
I've been studying all morning