DF7C型机车抱轴瓦油位过低，则润滑不良，容易导致轴瓦（）。
A、剥离
B、辗片或烧损
C、擦伤
D、松脱
参考答案：B
_____ for the breakdown ofthe school computer network, Alice was in low spirits. [ ]
A. Blaming
B. Blamed
C. To blame
D. To be blamed
土壤孔度
