????:1??????????:??????

2???????power

3????????

4???????

5??????

7????1???,?7??31?????????????,??300???????????????????20????????????,????????????????????,????,????

??,???,?????????????D6724???????????????,???????????????,?????????????16????????????,???????????10??????????????100???????????????

???????????????????????,??,?12306?????????????????????????12306???D6724??,??????,???

???????????,????????D6724????????,??????????????,?????????????(?????????????? ?? ???? ? ?????????????????? ??????????????????)

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