???,??????8??7????????,?????????????????????????????“?????”?

??????????????,???“????”???????5?????,???????,???????????????????????????????????,????????????,??,?????????(? ?? ??)

???:?????

“??sn??”_????

?? ???:“??”“???” ????????

????:1???sn??:??????

2?????????

3?????????

4????????

5??????

???,??????8??7????????,?????????????????????????????“?????”?

??????????????,???“????”???????5?????,???????,???????????????????????????????????,????????????,??,?????????(? ?? ??)

???:?????