Affirmative: a) I have been painting for two hours.
b) He has been doing his homework since 8 o'clock.
Negative: a) I haven't been painting for two hours.
b) He hasn't been doing his homework since 8 o'clock.
Interrogative: a) Have you been painting for two hours ?
b) Has he been doing his homework since 8 o'clock ?
Sper ca ti-am putut fi de folos !