下载APP
举一反三
【单选题】Subways are underground trains, which usually operate 24 hours a day. They are found in larger cities and usually run between the suburbs and the downtown area. Maps and schedules are available from t...
A.
within downtown areas
B.
away from city centers
C.
in or outside big modern cities
D.
between suburbs and city centers
【单选题】允许速度不大于80km/h正线及到发线道岔地段，，轨距的静态几何不平顺计划维修容许偏差管理值为（）mm。
A.
+2,－2
B.
+3,－2
C.
+4,－2
D.
+5,－3