What is the difference between have been and had been?

have been is plural past tense meaning more than one had been is singular past tense meaning only one ie they have gone... or she had gone...

AnswerThe difference has to do with the completion or the continuance of the past action. There may be other ways to think about or to use these forms.

I have been playing the piano for nearly 50 years. [Or: you have been; he has been; we you or they have been] The implication is that playing the piano is a past action that is continuing.

I had been a graphic artist before beginning my career as an architect. [Or: you, he, we, they had been] The implication is that work in graphic arts was completed at some time in the past before something else took place.