??? ??????? ???? ?? ??? ??? ??????? ?? ???????? ??? ???? ????? ???? ????? ????? ?? ????? ??????? ??? ?????.six – The ability to practice the trainees to use the maintenance and mend manuals in a complicated civilized way.???????? ??? ???? ???? ??????? ???????? ????? ?????? ????? ???? ????? ??????? ??? ???? ?????? ?????? ????? ????????.??? ???? ??