单项选择题
A.galvanized to protect against corrosion
B.held in place with heavy materials such as spare pendant wire
C.limited to no more than five courses high
D.provided with bulwarks at both ends of their bays
单项选择题 In preparing a cargo space for receipt of a shipment of bagged cargo，which instruction for laying dunnage should be followed? （）
单项选择题 In order to minimize the effects of a tender vessel，when carrying a cargo of lumber，you should（）.
单项选择题 In observing rig motion while under tow，the period of roll is the time difference between（）.