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單項選擇題

The piston ring grooves for a standard engine are （）

A.chromium-plate against wear
B.anti-corrosion treated
C.white metal lined against wear
D.flame hardened against wear

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單項選擇題

The piston moving up and down keeps the crankshaft （）.

A.to revolve
B.revolved
C.revolving
D.to be revolved

單項選擇題

The piston moves up and down, thus causing the rotational movement of the（）

A.crankshaft
B.connecting rod
C.cross-head
D.main beating