【单选题】根据《通信建设工程安全生产操作规范》,关于安全带的使用,描述正确的是()。
【单选题】安全带应在使用 _____年后,按批量购入情况,抽验一次
【单选题】链条铰链(或铰链销轴)的磨损,使链节距伸长到一定程度时(或使链节距过度伸长时)会 ( ) 。
D.
使链条铰链与轮齿的啮合情况变坏,从而发生爬高和跳齿现象
【判断题】安全带应在使用2年后,按批量购入情况,抽验一次。安全带的使用期限为3-5年,发现异常应提前报废。
【判断题】凹模型孔表面粗糙度要求通常为Ra=1.6μm
【单选题】三段式电流保护回路中,接通信号装置的二次设备是:
【单选题】听力原文:M: Have you called John to come and fix the TV? W: I tried reaching him again and again, but it seemed his phone was out of order. Q: Why couldn't the woman get John to come? (13)
A.
John's phone wasn't working.
B.
John wasn't at home when she called.
C.
The woman didn't get the right phone number of John's.
D.
John was too busy to come.