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????????????????????????????2?????18???????????? (?? ????????)???18?,?????,???????????“?”,??????????,???????“????????”????,???????????????,???
??“?????”?????????????????,??????????????????????????,?????????,?????????50??(????????????)???,?500???,??1-3?????????????,??0.3%-0.5%/???????????????,??????????,?????,?????,??,???????
???????????????,“??????”????????????????????,????????????????????????,?????????????,??????????????20??(????????????)???0.3%/??,20???0.5%/???????????????????????????????????????????????
???????,????????“?”?????20????????(??)???,?????????20???,???????????????????,??????????????????????????????????????????????????????????????(????????) ?????:??????????????????????
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