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單項(xiàng)選擇題

Marine four-stroke diesel engines are mainly （）.

A.of crosshead type
B.of trunk piston type
C.of low speed type
D.all the above

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單項(xiàng)選擇題

Main bearings are required to support the crankshaft at each （）.

A.end
B.web
C.pin
D.journal

單項(xiàng)選擇題

Lubricating oil for an engine is stored at the bottom of the （）, known as the sump or in a drain tank located beneath the engine.

A.sea cheat
B.air receiver
C.crankcase
D.water box