?? ??????????????:???????
![](https://image.chezhanri.com/2019/1112/17cc663b4ac9f890aa2aef224ece42ef.jpg)
????:1???????????:?????????
2??????
3???????????
4?????
5????????
???????????(?????????? ???????????????)???????????,??«??????????????????????????(??????????????????????)»???,??,?????
???????????????????????????????????,???????????????????????????,«??????????????????»?,?????,??????
????,??????????????????A?B?C?????????????,A???????????????????500???????????????????????;B????500??????????????????????????????;?????C??????
«???????»??,?????????????A??,???????????????????;B???????????;C???????,?????????????????,???????????????,???????,?????????,????????
??,«??????»??,????????????????30???????????,??????????6??????,???,?0.5????????????????????????????/?????
«????????????????»????,????????????????????????????????????????????,A???????1???????????????,?????????,??????????????????????????B????????1??,????????,?1????????C?????1????
???????,«???????????»?????,???,????????,????,??(?????) ????:??????