单项选择题
A.the cap should be removed to drain the boat when it is waterborne
B.the cage must be free of rubbish or the ball may not seat properly
C.there is an automatic ball check located in a siphon tube
D.the small lever to release the rubber ball float must be turned counterclockwise
单项选择题 In launching a covered lifeboat，what would safely lower the lifeboat from inside the lifeboat cabin?（）
单项选择题 In addition to the life jackets stowed at each berth location，life jackets must be stowed at each watch station and（）.
单项选择题 If absolutely necessary，the best way to land on a beach in a motor lifeboat is to（）.