单项选择题
A.one engine ahead and one engine astern，with full rudder
B.one engine ahead and one engine astern，with rudders amidships
C.both engines ahead，with full rudder
D.both engines astern，with full rudder
单项选择题 On a single-screw vessel the stern frame（）.
单项选择题 On a ship，the possibility of a blowout makes which type of diesel engine shutdown desirable?（）
单项选择题 My ship’s engine responds well to telegraph orders and takes about 80 seconds to reverse from full speed ahead to full speed astern.This sentence（）.