?? ???19.4????????????????????
????:1??????:????vx?
2????????
3??????
4?????????????
5?????????
??9?27?? (?? ????????????)???27?,?,????19.4?????????????????,?????2.77?????
????????,???????????????????80%,????????????????????????15.26??,??????20%???????????????????,???????
????????10?????1??????????,???10??????????5?????????????????????????,???9????????????30??,??????????????????????????,????????,???,???
?????????????????????????,???????????????,????????????????
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