???????? ???? ? ??? ?? ?? ????????The two most common grammatical principles in which this occurs is when conjugating prior to now or present tenses. For illustrations:*?????? ?????? ?????? ?????? ??????????????.?? ?? ???? ?? ??????- ???? ??(?????????? ?? ??) : ??, ?? ??????, ??, ??, ??? ????? ?????? ??????, ????? ??? ??? ????? ??? ???? ???? ??, ??