?? ?? ???? ?? ??????The two most commonly encountered grammatical principles in which this occurs is when conjugating in past times or current tenses. For examples:?? ?????? ?? ?????? ???? ????. ??, ?? ?? ??? ?? ?????????? ?? ?? ?????????????????? ???? ???? ?? ???? ?????? ??- ???? ??: ??, ??, ?????????????????, ????(??, ???????? ??), ??? ????? ????