Will anybody in this forum give me several model ‘can have been’ sentences?
Try HERE.
“Can have been” is mostly used in questions or with negations, but often “could have been” sounds slightly better.
When you want to express a plain possibility, it sounds a bit odd to me; “may have been” often sounds more natural.
“Can have been” is also used to echo an earlier use of a similar phrase, which is fine.
A: - During our phone calls, Peter assured me he fed my cat every week, but now she is dead!
B: - Can he have been lying? [Question: possible, though I’d say “could he have been” is better here.]
A: - No, he can’t have been lying, he has been my best friend for years. [Negation: quite alright, although “couldn’t have been” is very well possible.]
B: - He can have eaten her when he was very hungry. [Plain possibility: this is sometimes done, but I find it ugly: “may have eaten” is much better.]