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

2??????????

3???????

4???????

5??????

?????2?????13??????????????????? ????(CBC)???????,?????????????????????12??,??“??????????”???51???

???:??

?????????????,“????51????????,????????????????(???)?,???,????”

2???????7???,????????,?????????????????????“?????????”,???????????

??,??51??????,????????“???”???

??:????