单项选择题
A. derrick boom rest B. derrick head C. derrick mast D. derrick guy
The （）(千斤滑车) can run the gooseneck.A. heavy derrickB. p...
单项选择题The （）(千斤滑车) can run the gooseneck.
A. heavy derrick B. pulley block C. topping lift block D. guy tackle
The （）(重吊杆) can lift heavy cargo.A. heavy cargo derrick...
单项选择题The （）(重吊杆) can lift heavy cargo.
A. heavy cargo derrick B. heavy deck C. jumbo boom D. heavy block
The（）(千斤索) is a wire used to take the weight off.A. lig...
单项选择题The（）(千斤索) is a wire used to take the weight off.
A. light derrick B. union purchase C. topping lift D. heavy derrick
