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單項選擇題

（） is made of a boss with separated blades mounted into it.

A.A variable pitch propeller
B.A variable pitch nut
C.A fixed pitch parallel
D.A fixed pitch screw

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單項選擇題

（） is fully floating in both connecting rod small end and the piston skirt.

A.The piston rod
B.The cross head pin
C.The gudgeon pin
D.The crank-pin

單項選擇題

（） is arranged for cleaning the lubricating oil in the system and clean oil can be provided from a storage tank.

A.A filter
B.A centrifuge
C.A distiller
D.A generator