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

2???100????

3????????vx

4?????

5?????vx

?????????????????????12??????????20?????????? ?????12?20????????,12??????19???????????????,???

??????????????????????????80????????????????,????????????????????????,????????????????,??????,?,??????????????????????

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

20??,?????????????????????????80????(?????????????????????????) ???????????????:???????