?2????????17? (???????????? ???????)???17???????????,??,2???13???????16??????,??????????????????,????????????72????????????????????15.3?,?????;?????????10?48??????????6.5?~10.9???,?;????????????????????????????4??????????????

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

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

??2?????????????????18??????????????2??22??????????,??,???????????????,????2???????19???2???20??,????????,????????,????????????????,??,??(?)

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

??

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