12???21????????????????,????,???,???????????????“?”???????????????,?????“???”,???????????????????,?????????????(????)? ???????? ??????????????? 12???21???????,????????????????,????????“????????”?????????????????,?“?”?,???????“????????????”,?,???????? ????? ???? 12????????21????????,????,????????“???????”????????,??????“?????”???????????????,?“???????”,???????????????????,????????????????????? ? ? 12?21???????????????????,????,???????????????????“????????”??,?????“?”????,????????????“????????????????”,????????????,????????????? ???? ???? 12????21???????,????,???????????????????“????????????????””????????,???????????????????“????????”???????????????????,???????????????“???”,?????,???????????? ???? ???????????????? 12???????????????????21????,???,????“?””?????,??????“????????????”???,?????“?????”,?????,??(?)???????????? ???? ??????????????????? 12?21????,???,?“?”?????????????,????????????????“????????????????”????????????,????????“???”,?????,????????????????(????)?????? ? ????? 12??21?,????,????“????????????”????????????,????“????”????????????,?????“????????”,????????????,???????????? ??????? ? 12?21????,???????????????,????“????”????????,???????“?????”?,????“?????”,????,?????(???????????????)??? ???????????????? ????????????? 12????21????,???????????????,??????????,???????????????“?????”???????,?“????”,?,?????? ??? ? ????????????????????:????? “???????????”????

?? ????“????????”???

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

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

3?????v

4??????????

5????????

12???21????????????????,????,???,???????????????“?”???????????????,?????“???”,???????????????????,?????????????(????)? ???????? ??????????????? 12???21???????,????????????????,????????“????????”?????????????????,?“?”?,???????“????????????”,?,???????? ????? ???? 12????????21????????,????,????????“???????”????????,??????“?????”???????????????,?“???????”,???????????????????,????????????????????? ? ? 12?21???????????????????,????,???????????????????“????????”??,?????“?”????,????????????“????????????????”,????????????,????????????? ???? ???? 12????21???????,????,???????????????????“????????????????””????????,???????????????????“????????”???????????????????,???????????????“???”,?????,???????????? ???? ???????????????? 12???????????????????21????,???,????“?””?????,??????“????????????”???,?????“?????”,?????,??(?)???????????? ???? ??????????????????? 12?21????,???,?“?”?????????????,????????????????“????????????????”????????????,????????“???”,?????,????????????????(????)?????? ? ????? 12??21?,????,????“????????????”????????????,????“????”????????????,?????“????????”,????????????,???????????? ??????? ? 12?21????,???????????????,????“????”????????,???????“?????”?,????“?????”,????,?????(???????????????)??? ???????????????? ????????????? 12????21????,???????????????,??????????,???????????????“?????”???????,?“????”,?,?????? ??? ? ????????????????????:?????