单项选择题
A.change from diesel oil to heavy fuel oil for mail engine
B.pump out bilge water
C.change sea chest form lower level one to high level one
D.test emergency generator
单项选择题 Most often （） is attached to the engine-propeller shaft for efficient electric power generation.
单项选择题 In today’s practice, with cylinders of equal diameter of bore and equal revolutions, the two-cycle engine delivers a power about 80 percent （） than that of the four-stroke one.
单项选择题 With（） the engine need not to be aligned with reduction gears or propeller shaft.