单项选择题
A.定时B.定量C.定性D.定期
A.热熔连接B.卡扣连接C.焊接D.粘接
A.250HzB.200HzC.150HzD.100Hz
A.400mm,30mB.500mm,30mC.600mm,50mD.800mm,50m
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