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