单项选择题
A sea anchor is（）.
A.a heavy anchor with an extra long line used to anchor in deep water B.a cone shaped bag used to slow down the wind drift effect C.a padeye to which the sea painter is made fast D.made of wood if it is an approved type
单项选择题 A self-contained breathing apparatus is used to（）.
单项选择题 A set of interior steps on a ship leading up a deck from below is known as（）.
单项选择题 A sheave is a（）.
