This is how I would position the adverbs in the following sentences:
Jan can't ever have seen a mobile phone before.
Arnie must have undoubtedly been treated badly.
If my word order is correct, can someone please provide a rule for both cases? I haven't been able to find one that would deal with cases where there is a modal and present perfect in one sentence.
Thank you very much for shedding light on this. Mel.