?? ??? ??4?????????
????:1??????????????:???????
2???????
3??????????
4???sn??
5???????????
??11??29?? ??????????????????????,??????29?,??4???????29??????????,?????,??????“??”?
?????????????29????????????????,??????????7??27?????????????????????????????????????29??,????????8???????????,????????????????????6??????????
?,????????30????????,??????????“??????????????”,??????“???????”?
?,??????,???????????????,????????????????,???????????????(?????) ???:?????