单项选择题
An effective braking system for windlasses on rigs in deep water is a(n)（）.
A.larger chain stopper B.disc backstopping brake C.hydraulic clutch D.electrical regenerative braking system
单项选择题 A wooden plug fitted tightly in the vent of a damaged tank may prevent the tank from（）.
单项选择题 A tackle is two blocked when the blocks are（）.
单项选择题 A sweep oar is an oar that is（）.
