????????????11??17??????19????,??,?????

??,?????????“???????”????????????(G20)?????“??”,?????“G20?”???????????????????????,?????????????,???????????G20?????????????????????????????,???????????

?????:??? “?????”????

?? ??:??????????????G20??????

????:1??????:?????????

2???????????????

3?????????

4????????sn

5??????

????????????11??17??????19????,??,?????

??,?????????“???????”????????????(G20)?????“??”,?????“G20?”???????????????????????,?????????????,???????????G20?????????????????????????????,???????????

?????:???