????????????????? ????????????
??2??????13???????? ????13??????,??????,???????????,??????????????????????????????????????????6~8??,????10~12???????,?????????????????4~8???????????????????????,?????10??
??,????,?????????????????????????4~5?????????????,?????4~6?????????????????????6~7???
?,???14??15??,??????????????????????????????,??,??????????;??,??????????????????????????????????????????,???
??????,???????????????????,??;??????????,??,?????
???:????????????????