高速客运内燃机车牵引电机采用全悬挂方式，电机与轮对用空心轴连接，彻底解决了（）故障。
参考答案：抱轴瓦碾片
--- Tom, why didn’t you come to the meeting yesterday?
--- I _____, but my car broke down.
A．would
B．had
C．was going to
D．did
干混砂浆浆料制备时待检样品应在试验条件下放置（）以上。
A.16h
B.20h
C.24h
D.30h
