单项选择题
A.大于50%,小于25% B.大于75%,小于50% C.大于75%,小于25% D.大于50%,小于15%
A.10mm-15mm,5mm-10mm B.8mm-10mm,5mm-8mm C.5mm-10mm,1mm-5mm D.2mm-5mm,1mm-2mm
A.晶粒直径0.01mm-0.05mm B.晶粒直径0.05mm-0.10mm C.晶粒直径0.01mm-0.10mm D.晶粒直径小于0.01mm