????:1?????????:??????

2?????

3???????

4?????sn

5???????????

????,?“????”??????????????,??????“???”???,????,????“??????????”??????????,???????????????????????????,«??»«????»«????»????,??????????????

????,????????????????9??????????????????22???10?????7????,??“1+3+6+N”????,??????????????????,???????????,?????

(? ?? ??????????? ??????? ?? ?????)

?:??????????