丝锥属于手动工具中的()工具。
A、切割类
B、紧固类
C、套丝类
D、弯管类
参考答案:C
__________ the assignment made his father lose his temper.
A.The boy’s not having done
B.The boy not having done
C.The boy’s having not done
D.The boy having not done
故障模式是指故障的表现形式,下列属于损坏型故障的是()
A、断裂、碎裂、开裂、点蚀、烧蚀、变形
B、老化,变质、剥落、异常磨损
C、松动、脱落
D、压力过高或过低、性能衰退、公害超标