单项选择题
A.0.20~0.30 B.0.35~0.55 C.0.60~0.70 D.0.75~0.85
A.0.20~0.40 B.0.45~0.60 C.0.65~0.70 D.0.75~0.85
A.端隙 B.背隙 C.边隙 D.间隙