单项选择题
With UMS, when the engine room is unwatched （） will control the main engine.
A.the bridge officer on watch B.the chief engineer C.the duty engineer D.the duty motorman
单项选择题 （） handle and instruments are on the front.
单项选择题 The （） is a crystal which, under pressure, produces an electric current which varies with the pressure.
单项选择题 Remote control means that （）.
