?? ???? ???????? ?????? ????????? ?? ??????.??????? ???? ??? ???????????? ???????? ??????????. ??????? ???? ??????????.?? ???? ??????, ???? ???? ???? ?? ??? ??????.???? ???? ??????, ???? ?? ???????? ?? ?? ?????? ???? The 2 most frequent grammatical concepts exactly where this happens is when conjugating before or present tenses. For illustrations:?