????:1???sn??:????

2???sn??

3????????????

4??????

5????????

??2??????????5?????? (???????????????? ?????????????? ????????????????????)???????????“???”?2???5???,???????????????,??????

?????????????????,??,???????????????????,?????????????,?????????????,?????????????????????????????,????

??????????????????,???,????“??????????????”????,?,?????????,????????????????????“??”??“????”;????????????“???????”??,???????????,?????????????????????;???????????????????,??“????????????????”;?????????????????????,?????

???????????????,?????????,????????,?????????????????,???????????,????????????????,??????????????

????,????????????????????????????????????????,?,?????(?????) ????????:??????????????????