单项选择题
A stage should only be rigged（）.
A.over the bow or stern of a vessel B.over the flat sides of a vessel C.over the open water D.over the dockside
单项选择题 A squeeze-grip type carbon dioxide portable fire extinguisher has been partially discharged. It should be（）.
单项选择题 A special daymark is a（）.
单项选择题 A spanner is a （）.
