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單項(xiàng)選擇題

If a gasoline engine turns over freely but will not start，the cause is generally（）.

A.a defective ignition system
B.low lube oil level
C.weak valve springs
D.too heavy a load

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單項(xiàng)選擇題

Each cylinder in a two stroke cycle engine experiences combustion（）.

A.once each crankshaft revolution
B.twice each crankshaft revolution
C.every other crankshaft revolution
D.every fourth stroke

單項(xiàng)選擇題

Centrifugal pumps have what advantage(s) over reciprocating pumps?（）.

A.They are less expensive
B.They are smaller for equivalent pumping ability
C.They pump more cargo in less time
D.All of the above