?? ????????????? 3???
????:1????????:??sn
2????????
3???????
4???????
5?????300?3??????
10?2???,??????????,???????500???
???3???,???70?????
?????,???????,???(???????????????? ??? ????)
????????????:????10?2???,??????????,???????500???
???3???,???70?????
?????,???????,???(???????????????? ??? ????)
????????????:????????:1????????:??sn
2????????
3???????
4???????
5?????300?3??????
10?2???,??????????,???????500???
???3???,???70?????
?????,???????,???(???????????????? ??? ????)
????????????:????