How can you estimate the position of a tropical storm’s center?（）

A.Require a demonstration by the officer and the crew member
B.Require a written test
C.Require that an interpreter be provided
D.All of the above

A.The faying surfaces are coated with white lead (or similar product) before the rivets are set
B.A sealing weld bead of 1/8" or less pitch is run along the plate edge
C.The plate edge is split close to an adjacent plate and mechanically forced into contact with the adjacent plate
D.A properly riveted joint will be watertight; any leakage is stopped by setting up on the rivets

A.less moisture than cold air
B.more moisture than cold air
C.the same amount of moisture as cold air
D.moisture independent of air temperature