相关考题
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单项选择题
When the derrick is stopped, the guy must be （）(收好).
A.taken in
B.slacked off
C.adjusted
D.stowed -
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 -
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
