??????“???” ?????????

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

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

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

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