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單項選擇題

The two-stroke cycle begins with the piston coming up from the BDC, with the scavenging ports in the sides of the cylinders being （）.

A.open
B.uncover
C.covered
D.closed

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單項選擇題

Hearing a strong noise, （） at once.

A.the engine stopped
B.the engine was stopped
C.he stopped the engine
D.he had stopped the engine

單項選擇題

（） that everything in the engine crankcase is correct, start up the crankcase lubricating oil pump.

A.To satisfy
B.To be satisfied
C.After satisfying
D.After being satisfied