单项选择题
Tugs sometimes shackle a length of chain in the towline in order to（）.
A.take the wear should the towline drag bottom B.assure that if the towline is overstressed it will part close to the bridle C.prevent the towline from whipping should it part D.put spring in the towline
单项选择题 Towlines should be inspected for chafing where the towline（）.
单项选择题 The strongest of the natural fibers is（）.
单项选择题 The spray of water in low-velocity fog will have（）.
