单项选择题
A.0.5-1mmB.1.5-2mmC.2.5-3mmD.3.5-4mm
A.0.5mm-1mmB.0.5mm-0.75mmC.0.75mm-1mmD.0.25mm-0.75mmE.0.25mm-0.5mm
A.向下,向下B.向上,向下C.向上,向上D.向下,向上