?? ?? ???8???15??????????????
????:1???????:????
2?????????????
3???sn??
4???????????
5???????
?1?4??????? ?“???”???????,??,1????4????????????????????8??40???????????????,????????,????????????10??10????????????,??????????????????12?50?,?????8?????????,15???????????,????
??
?:“??”?????? ????:?????