???????? ???? ? ??? ?? ?? ?????????? ?? ?? ? ??? ???? ??? ????? ??? ???? ??? ??? ??? ? ????. ???? ?? ??? ??? ??? ? ???? ???? ????? ?????.If a grammatical principle that may be additional to ????is a vowel ??and there is no other selection besides a vowel ??then that grammatical principle cannot be included to ????????, ?????