单项选择题
Ropes can be divided into （）basic types.
A.3 B.4 C.5 D.6
单项选择题 It is very important for every sailor （）the characteristics of the ropes so that they can be for right jobs.
单项选择题 This windlass （）now.
单项选择题 The blocks and gooseneck of the jumbo need （）.
