?? ??12306??????????? ????????
????:1???????????:????????
2???????????
3???????????
4??????
5?????V
?9??????????????25???????????????? ??????????????“????????????????”??????????,???,??12306???????????App??,???????,?“?????????????????”???????????,??,???,???????????,???????????????
??????????????????????????????,??????,????????????,??????????,??????,??,????????
??:?????????????,????????????????????,????A??+????????B????????????;??????????????,?????????C?????????????????+??D??? ???:??????