单选题Ring groove inserts are occasionally used on aluminum alloy piston to（）Areduce the ring groove wear rateBseal against crankcase vaporsClessen the wear on aluminum part of the cylinderDallow for the greater expansion rate of aluminum
单选题
Ring groove inserts are occasionally used on aluminum alloy piston to（）
A
reduce the ring groove wear rate
B
seal against crankcase vapors
C
lessen the wear on aluminum part of the cylinder
D
allow for the greater expansion rate of aluminum
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