相关考题
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单项选择题
The（）(贵重货) must be kept carefully.
A.VC
B.PC
C.A+B
D.NC -
单项选择题
The （）(支索)is important to a derrick.
A. block
B. guy
C. stay -
单项选择题
The （）(吊杆托架) supports the derrick.
A. derrick boom rest
B. derrick head
C. derrick mast
D. derrick guy
