单项选择题
A chock is a（）.
A.deck fitting used to secured mooring lines B.casting fitting at the side of a weatherdeck, used as a fairlead C.sharp block of wood used to support hygroscopic cargo D.smoke pipe for the galley stove
单项选择题 A C02 portable extinguisher is annually checked by（）.
单项选择题 A contra-guide is a type of（）.
单项选择题 A dead reckoning (DR) plot（）.
