?2??18???????????? (????? ?)??18???,????????????????????,???“??”,???????????????????,?????????????“???????????”??,???????,???

???“??”?????????????????????????????????????,?????????,???????,???50???(???????????)?????,??????500????,?????1-3??,??????0.3%-0.5%/??????????????,???????????????????,?????,???,????????????,?????????

??,“?????”????????????????????????????????????????????????,????????,??,??20?????(?????)????????0.3%/???,20?0.5%/??????????????????????????????????????????????????????????????

?,???“?”????????20???????(????????)????????????,???????????20?????????????????????,????????????????,????????????????????????????????????????????????????????????(????????) ??:????????????????

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