????????????8???????????
?????2??21?????????????????????? (???????????? ???)21???,?????????????????8???
?????????,???????????,????????,???????????4???????????????4???????????????????,????????????????????????????,?“??????????????????????”????????????????????,???????,???????????????????????????
????????????????????,?????,?????????,?“??”??????????“1+N”?????,?????????????,?????,??????,???????,??????,???????????????????,??????????????,???????????(???)

??
???:????