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

??:???

??

??:???????????,??????????,??????????????