I don't want to make them passive, I just wanted to know if there really is no passive form for those Perfect Progressive tenses while every other tense has a passive voice though.
E.g. Present: "Tom writes a letter" --> "A letter is written by Tom"
Present Progressive: "Tom is writing a letter" --> "A letter is being written by Tom"
Present Perfect: "Tom has written a letter" --> "A letter has been written by Tom"
so as a logical conclusion, I thought, there maybe could be a passive also for Present Perfect Progressive - and just because of the fact that passive is built by forms of
"to be"+past participle,
I concluded, it could be "have been being+past participle", equal to the other passives.
Is it also not possible to say
"A letter will be being written by Tom", passive of "Tom will be writing a letter",
built equal to Present or Past Progressive tense?
![Wink [;)]](/emoticons/emotion-5.gif)
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Thanks for your help!