单项选择题
The net productivity per gang-hour can be improved through a decrease of（）.
A.Cranes/derricks B.Crane/derrick cycles C.Crane/derrick cycle time D.Weight per package
单项选择题 The Master or person in charge of a ship shall ensure the crane record book shows the（）.
单项选择题 The item（）is not the advantage of the hydraulic winch．
单项选择题 Sudden starts or stops of the boom is likely to cause all of the following except（）.
