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

2???????

3???????????

4??????????????

5?????vx

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

??????,??????????,??????????????8???,?????????????????????????????????????????????????????????????????????????????,???7??????????????????????????114?????????????

??????????????????,???,??????????????????647.81???????????????????????????????????????????8?????30%40%,???,??16?????????,??100????????????,???????????????,?????????,????????????????21???51????????????,???????????????,????????????????450??,???????????????????500????????????????

?,????,??1?????????,?????????????

??????,?????????????????????????????????????,???????????,????????50%,???????????????35%?

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

?,??16.4%???????????????38.1%?34.6%???13.2%? ???????????:???????????