单选题In a four-stroke engines the camshaft rotates at （）.A half the engine rotational speedB twice the engine rotational speedC the engine rotational speedD four times the engine rotational speed

If all other conditions such as bore, stroke, speed, and mean effective pressures are equal, a two stroke/cycle diesel engine will develop approximately

A.the same indicated horsepower as a four-stroke/cycle engine

B.twice the indicated horsepower as a four-stroke/cycle engine

C.one half the indicated horsepower as a four-stroke/cycle engine

D.one power stroke for every two crankshaft revolutions

Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because________.

A.The direction of pressure on the journal in four-stroke engine is continuously

B.positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engine

C.four-stroke engines usually utilize a heavier grade of oil than tow-stroke engines

D.Low-stroke engines usually consume less lube oil than four-stroke engines

---Slow ahead both engines! ---Slow ahead both engines! ___________________!

A.Both engines slow ahead

B.Engine slow ahead port

C.Engine slow ahead starboard

D.Engine both ahead