?? ?????? ??? ???????????? ?????? ??????? ???????? ?????????? ??? ????.The 2 most popular grammatical concepts where this occurs is when conjugating in past times or present tenses. For examples:?? ???? ??????, ????????????, ???? ???? (???????? ??)???????? ???????????? ?? ??? ?????? ???? ??????????? ????? ???? ?????????? ???? ???????? ????? ?? ??