单项选择题
You are operating a lift boat.When beginning to jack down you should（）.
A.Jack down one leg at a time B.Jack up first，then down C.Undog doors to the engine room D.Assemble all personnel on the main deck
单项选择题 You are handling a mooring line and are instructed to Check the line.What should you do（）.
单项选择题 Which will cause a wire rope to fail（）.
单项选择题 Which type of link is generally used to connect shots of anchor chain（）.
