单项选择题
A pelican hook（）.
A.Can be released while under strain B.Is used for boat falls C.Is used for extra heavy loads D.Is used for light loads only
单项选择题 A common class of wire rope is the 6X37 class.What does the 37 represent（）.
单项选择题 A Chinese stopper（two lines）will hold best when you（）.
单项选择题 A chain bridle is used when towing astern because it（）.
