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

2?????????

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

4???????

5?????vx

??????????2??????????????????????????????21??????? (?? ???????????????? ?????????????)????,??-??????(??????????“??”)???????????????????

?? ??????????????? ???????????????

????21??????????????,??,??????????????????,?,?????????????2????????20?,??200????,??????????????800????????????????,???????900?????????????????

“????????????15??!??,??20%,????????30%?”??,?????????3?????????????125????????????????

???????? ?? ??

???????,?1838????????,?????22155???“??”??????????????????“???????????????????”?????

???????????????? ??????? ??????????

?,??,????????????????????????????,?????,?????????????,?????????????????????????????100???,???????6000????,???????????????????7000??????????????????(??)

??:??