??
?????2????3???? ????????????,?,2?????????3?????????????20??4????20?????,?????????????????????????????????5~6???????7~8??????????,?,??????????????6~8?????9~10??????????????????????????????????????????????????????????7~8????????9????,??????9???????10???????
2??4????20??5???????20?,????????????????????????5~6???????7~8???,???????????6~8????????9~10??;?????????????????????????????????????????????????7~8???????9?????,???9?????????????????10???????????????
?????????????????????:
1??????????,????????????;
2????????????,????????????????????;
3???????????????????,???????????;
4????????????????,????????????
???:???????????????
???????????????????:??????9?10??????????????