A.工務(wù)段查詢終端B.車務(wù)段查詢終端C.動(dòng)車段查詢終端D.電務(wù)段查詢終端
A.向上B.向下C.居中D.關(guān)閉
A.450HzB.550HzC.650HzD.750Hz