?? ????15??? ????50??????????
????:1???????????:???????
2????????????
3?500?3????
4???????????
5???????98???
???6?21???????????????????????????? ?(ABC)??????,????????????????????????????20???,??,????????????19????,???15????
??:?????????????(ABC)?????,???????,???????????,?????
????,????????,??????????,????????????20?30??????????????,?????????50???????????
?????,?????????????????????
?,??????,????
???????????????:?????