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

2???400??????

3?????????

4?????vx

5???????a???

?????????????12?????????27????? ??????????:????????????????????????,????,????????????????

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

???????????????????????????????????,???,????????,???,??????,????????????????????«??????????????»«??????????????????????????»«????»?????,???????????,????????????????????????????????????????????;???,???????????;????????????;???????????,????,??? ???:????????????????????????