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

2????F?

3?????vx

4????????

5??????????

“???”?????????????????????????,?????“????????”??????,??????,?????,??,??????????,????????????????,???????,??,???

????????????????????????????????????????……???????????????,???,??????????????????????,????,??????“??????”?????????????“??”????“???”??????????“??????”,??,??????,??(????? ????? ?? ??)

?:????????