??? ?????? ????????? ???? ?????????? ????The two most common grammatical principles the place this occurs is when conjugating previously or existing tenses. For illustrations:- ???? ??: ??, ??, ??(??, ???????? ??), ??????, ??, ???????(??)?? ?????? : ??, ??, ????, ??, ???? ?·???????, ?? ?????? : ?????? ?????????? ??·??????????????????????? ???? ??