??:7?????? ?7?8?????????

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

??2????16?? ??,???????,2???????????16????20???????17?????????20????,????????????????????????????????????4~6?????7~8??;??????????????????????????????????????????7????8??

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

??:

1????????????????????,?;

2?????????,???????????????????;

3?????????????????????????,?????????????;

4???????????????????????????????,????????

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