单项选择题
When a vessel is in dry-dock, the vessel’s engineers should （）.
A.examine the condition of the propeller B.chip and paint all hull protection zincs C.install new docking plugs in all cofferdams D.inspect the hull for hogging or sagging
单项选择题 Air line lubricators are used in compressed air systems to lubricate （）.
单项选择题 Which of the listed devices would be installed at a control system air pressure reducing station?（）
单项选择题 Power is defined as the （）.
