单项选择题
The load chart of a ship crane enables the operator to combine the load radius with boom length to determine the（）.
A.maximum counter weight required B.minimum horsepower required C.hoist rope strength D.allowable load
单项选择题 The boom indicator tells the operator at what angle the boom is compared to the（）.
单项选择题 The boom indicator on a crane will indicate the（）.
单项选择题 Stop（）the derrick at once，the gooseneck is bent.
