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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

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（） 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