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

2????????

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

4????????????

5?????sn

?11??????25???? (???? ????????????)??????25?,??“??????????????”???????????,?????????,????????????????,????????????“?????????????????”?????,??

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

????,??????????????????????,????????????3.2??,????????????2.4?????????????????????????????????351.3????????????????????,???????3?????????????????????????????2.66??,????????????????????“??”????“??”???

????(???) ?? ??????????????????????

????????????????????????,??,??,?????????????????????,?????????????????????-???????????-????????????????????????-????????????,??,??,??????“???????”????????????

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

??????,?,?????;??,????,?????????????????????????

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

????????????????????:????????????????