Identification: when the work is going on but began in the past and there is indication of time. The time of the sentence is present.
1. I have been doing this work for 2 hours.
2. My friends have been coming to my house for weeks.
Helping verbs used: has been, have been
Affirmative: use of has been with he, she, it and singular noun; use of have been with plural noun, you and I:
1. I have been doing my work for many years.
2. She has been teaching in this school for many years.
Negative: use of has not been, have not been
1. I have not been doing my work since my injury.
2. She has not been teaching here since her marriage.
Interrogative: use of has or have at the beginning of the sentence
1. Have you been going to school for the last 2 months?
2. Has he been drinking coffee since the doctor advised him against it?