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

2??????????

3?????????

4??????????

5??????????

????????????12?????????????????????17??????????????? ?17??????????????????,????????,?????

???????,12????????????????????16??????????????????????,?????????????????15?????????????????????,????????????“??????????”???????

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

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

???????????????,????????????????,????????????????????????????(???????) ??:????????