1?????
????20??????30????????????????????????????????30?40???????????????5?10?????1??15?20??1??????1?2??????????????????????????????????
2?????
??50?????50????50?????30?????30??75%??500??????????????30???????????????????????????1?2???2?3????????????????????????????????????????????????????????????????????
3?????
???????10???????????????????????????????????????????????1????3?5??????5?7????????????????????
