????:1???150????:????vx

2??????

3?????200??500???

4???????

5???????100?

???????2?????????????????????11????????????????????????????(???????????? ????????)2?????11????????????,????????????,???,????????,???????,???

???????????????,????????1????????????,??,????????????????????????????????,?28????????????????50%???????????????????????,??,?????????????

?????????????????????????

???????????????,??,????????????,?,???49.9?,?????,?????,???(???????????????????????)

??:???