These phrases are similar to the ‘B family’ except that the period/time period comes in. As a person would say if he describes his experience. I have been a teacher for 10 years. Or he has been a good teacher. That is, there is an experience in the mind of how many years one has been a qualified teacher.
I have been [a teacher] for ten years.
I have been great.
I have been working since the morning.
I have been writing this letter for 10 minutes.
I have been teaching you English for 8 months.
You have been learning English for 8 months.
Apples have been eaten. (Passive)
I had been a teacher for 2 years.
I had been busy in a project for ten days.
I had been working since the morning.
I had been teaching in an academy before starting this course with you.
You had not been learning English before joining me.
They had not been working on that assignment.
I will have been a teacher for two years.
Will have been + Adjective
I will have been busy in a project for ten days.
I will have been working on my assignment for ten days.
You will have been writing me an email for ten days.
John will have eaten the apples. (active)
Apples would have been eaten by John. (passive)