单项选择题
A.直径 B.宽度 C.模数 D.齿数
A.a-b-c-e-f-d-g B.a-b-d-e-c-f-g C.b-a-e-c-f-d-g D.b-a-e-f-c-d-g
A.1.2﹪ B.1.5﹪ C.1.8﹪ D.2.2﹪