???????????? ??????? ???????????? ??? ??????? ?? ?? ???? ???? ???? ???????? ?? ???? ???????????? ??·????? ???????????????? ?? ???????????? ?????????? ?? ???????? ?????????????????? ??(?? ???? ???? ??, ?????? ????? ?????????????????. ??If a grammatical principle that is extra to ????is a vowel ??and there's no other alternative apart from a vowel