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