单项选择题
A.taken in B.slacked off C.adjusted D.stowed
When the derrick is topped, the guy must be （）(放松).A. s...
单项选择题When the derrick is topped, the guy must be （）(放松).
A. slacked off B. sent away C. sent out D. taken in
A （）(重吊杆)is used for lifting long heavy cargo.A. derric...
单项选择题A （）(重吊杆)is used for lifting long heavy cargo.
A. derrick B. crane C. jumbo boorn D. special crane
You should release the （）(重型螺栓)on top of the cover.A. l...
单项选择题You should release the （）(重型螺栓)on top of the cover.
A. lock in B. heavy bolt C. socket D. heavy cleat
