单项选择题
The boat is stowed on the davit rather than on a cradle with which type of davit?（）
A.Crescent B.Sheath-screw boom C.Quadrantal D.Radial
单项选择题 Static electricity may be built up by the（）.
单项选择题 Permission is kindly requested（）the ballast water.
单项选择题 On a ship，a door that is required to be marked KEEP CLOSED is designed to（）.
