大型养路机械车组自轮在施工区段内运行时,具有相同牵引特性的机械可同时发动用作牵引和推进,由处于车组前的第一位车担当本务机。
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In the suction stroke, the crankshaft is rotating clockwise and the piston is moving () the cylinderThe inlet valve is () and a fresh charge of air is being drawn or pushed into the cylinder by the turbocharger.
A. up;opened
B. down;open
C. up;closed
D. down;closed
异步电动机的转差率一般大于10%。
A. 正确
B. 错误
紧急避孕药能作为长期的避孕方法反复使用。
A. 正确
B. 错误