?? ????????????????:???2.5???
![](http://n.sinaimg.cn/photo/transform/200/w600h400/20180614/7vTl-hcwpcmr0180566.jpg)
????:1?????????:????
2???????????
3???????
4?????300?3??????
5???????
???????2??????????18?? ??18?“???????”???????????,???????????????,???????????????????????,?????????2???,??????????1900????????????;??2.5???;??1.2?????????????
????:????