单项选择题
A.FbbLs/4WB.Fbbl/2WC.FbbLs/2WD.Fbbl/4W
A.Frbl/4WB.Frbl/2WC.FrbL/4WD.FrbL/2W
A.±0.01mmB.+0.01mmC.-0.01mmD.-0.02mm