Good day!
How to choose a tense for the verb "be back"? By what rule?
(1) He has been busy since he has been back.
(2) He has been busy since he was back.
(3) He has been busy since he got back / returned.
They say only (2) is wrong.
How come (2) & (3) have the same tenses but (2) is wrong and (3) is right?
By what rule should we understand that (1) is right and (2) is wrong?
(4) Honey, I'm home, I'm back!
(5) Honey, I'm home, I've been back!
(6) Honey, I'm home, I've got back / 've returned!
They say only (5) is wrong.
How come (5) & (6) have the same tenses but (5) is wrong and (6) is right?
By what rule should we understand that (4) is right and (5) is wrong?
Why should "be back" and "get back" (or more formal "return") be used with different tenses in the same situations?
Thanks!
P.S.: "be back" is some strange verb. Maybe it belongs to some group where all such strange verbs are collected?