?? ????:???,“????”“????”???????
????:1???????????:?????
2??????vx
3????????????
4????????
5???????
????12??6?? 12?????6??,???
????:????????“????????”??????????
???:???????????“??”????,??????????????“??”??????????,???????????“??????????”???,????“????”?“??????”???
?,“????”???????“?????”?????,??,??;?,?????“??”??;??“?????????????”,?????????????????????????“????”????,????????????
?,????????,???“????????”???????????,“????????????????”“????”?????????,????????????“??????????”?,???????“?????????”??,??? ???:????????????????