A hook that will release quickly is a（）.

A.be a stopper
B.shorten a line
C.join lines of equal size
D.keep a line from passing through a sheave

A.rot
B.shrink
C.stretch
D.unlay

A.deck fitting used to secure mooring lines
B.casting fitted at the side of a weather deck，used as a fairlead
C.sharp block of wood used to support hygroscopic cargo
D.smoke pipe for the galley stove