单项选择题
Safety shackles are fitted with（）.
A.a threaded bolt B.a round pin，with a cotter pin C.a threaded bolt，locknuts，and cotter pins D.round pins and locknuts
单项选择题 Required lifesaving equipment on existing vessels may becontinued in use on the vessel if（）.
单项选择题 Lines passed around the falls to hold the boat while passengers are boarding are（）.
单项选择题 Life preservers should be stowed in（）.
