单选题In a four stroke engine, which process lasts the longest period?（）Aexhaust and suction processBsuction and compression processCcombustion and exhaust processDworking and exhaust process
单选题
In a four stroke engine, which process lasts the longest period?（）
A
exhaust and suction process
B
suction and compression process
C
combustion and exhaust process
D
working and exhaust process
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