????:????
??“??sn??”????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??????
??
??????:???? ?“??”?“??????”
??????:???? ?“??”?“??????”
??
????:
1???sn??:???????
2???????????
3????????????
4?????????
5????????
????:????
????
6
%
???:???