I was wondering where an adverb should (or could) be placed in the passive present perfect progressive in English.
I have been being carefully tickled.
I have been carefully being tickled.
I have carefully been being tickled.
An alternative position of an adverb is after the lexical verb, but I do not think that it is the only possibility.
I have been being tickled carefully.
Do all progressive tenses share this place for the adverb?
Please provided references and/or sources if possible.