Student or Learner
Man's voice: Oh, good morning. I want to warn you about a bomb...
Henry: A bomb? Where? Hello! We've been cut off. Operator! Operator! Operator!
Here, I didn't understand , why HAVE BEEN CUT OFF is used? We have been cut off is a complete sentence?? Why not " have been cutting off or are cutting off' ?
The use of present perfect here indicates an action completed in the very recent past (with present significance). The act of cutting off is sudden, so it wouldn't be in a continuous tense.
I hope this helps.