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.

单项选择题 Typical marine propulsion plants include（） directly coupled to the vessel’s single large-diameter, fixed-pitch propeller.