??????????? ???????15.3?
??2??????????17?????? (????????????? ???)?17????????????????????,??,2??13?16???,????????,???????72?????????????15.3?,???????;????????????????10???48?????????6.5?~10.9????????????,?????????????????;??????????????????4????
????????????,????????????,??????????????????????????????????
??2?18???????????????????2???????????22???????,????????,??????????????????,??2???19????2?20??,????,???????????????,????,??,??(????????????????)
???:??????