单项选择题
When using the term limber system one is referring to a（）.
A.Cleaning system B.Drainage system C.Strengthening system D.Weight reduction system
单项选择题 When lowering manropes alongside a stage rigged over the side of a vessel，they should be allowed to trail in the water（）.
单项选择题 What type of stern tube bearing has the least friction（）.
单项选择题 What is a cofferdam（）.
