?? ????????????????????????
????:1????????????:??sn??
2????????
3?????
4???????????
5?????
?9????????????28?????????? ?????????“??”?,9??????28??,???????,??????????????????????????????,???????????,?????
?????:?????????????????????????????????9????????????28?????????? ?????????“??”?,9??????28??,???????,??????????????????????????????,???????????,?????
?????:????????????????????????????????????:1????????????:??sn??
2????????
3?????
4???????????
5?????
?9????????????28?????????? ?????????“??”?,9??????28??,???????,??????????????????????????????,???????????,?????
?????:????????????????????????????????