????:1?????vx:??????

2?????

3??????????

4???sn??

5?????????

??????????6?????????????7?????????? (?????????? ????? ??????)??6???????????????????????7?:????????????????????????6?????10???11????????????????????????

????6??????????7???,???????????,????10??11???????????????????????,????????????

??,???????????????,?????????????????????????????

??,???,????????,??,??

“?,???”????????????????????????????????,??????????????????,??????????,?,??,???????????????????“?”???,??????????????“?????????”?????(???) ??????????:???????????