EGNLISH 現在完了形

https://3.bp.blogspot.com/-SjmN3Un3koc/VixBrhiJPYI/AAAAAAAA0EI/G8Yepe91DSk/s800/school_class_english.png

have been

have been pp

have been 名詞もあり得る

be動詞は形容詞or名詞を取るので