Generally, one working cycle contains four strokes.
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In the first stroke, both intake and exhaust valves are opened.
A. 对
B. 错
In the exhaust stroke, the piston moves downwards to push the burned gases out of the cylinder.
A. 对
B. 错
A spark plug is used to ignite the fuel-air mixture in the gasoline engine.
A. 对
B. 错
A cylinder head is a casting only made from iron.
A. 对
B. 错