?? ??????!????????????
????:1????????:??????
2????????
3???????vx
4?????
5?????????????
?,?????????????????????????6??????????????24??????,????????????,???????????????6??,??
??????,???????,??????????
????????????????????,????,????,????????????62.7????????????????????,???
?????????????????????????5?,????????????????,????????????????????????,?????4700????,????????????????????????????????65%???
?????,????????????????7??,8??9????(?? ????)
?????????????????:?????????