Just before the bottom of power stroke, the exhaust valve.
A. ups
B. downs
C. closes
D. opens
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Intake stoke_____ Internal combustion engine____ Lubricating system_____ Exhaust valve____ Cylinder block_____
Drum brake_____ Manual transmission___ Shock absorber____ Pitman arm____ Steering column___
Space utilization________ Loading state_______ Wind resistance_______ Rigid connection_______ Quarter window________
High-voltage spark________ Cruise system_______ Instrument cluster_______ Ignition switch_______ Winding coil________