?? ????????:??????????? ?????
![](https://image.chezhanri.com/2020/1217/4f88c0cde8c4f2cd5827e4de2bc87cde.jpg)
????:1?????????????:????????
2????????
3?????vx
4?????
5???????????
?????????????????????7?????8?????? (?????????? ??)?????7???????????8??,??????????????,???????????,????????,????????????
??????????????(?)??????,???????????????
??????????,??????????????????????,??????,???;?????????????????????????,????????????????,????????????????;???????,?,???????
???????????????????,?,???????????,???????????????????????????????????,??????????
??????????????????????,???8??????????????????????????,5???????????,????????????????,?????????????????
??????,?????,?????????,??????????????????,???????????
?????????????,????????????????????????(???????????????) ?????:???????????