单项选择题
A.一体铸钢 B.二分割铸钢 C.一体锻钢 D.二分割锻钢
A.4000r/min B.4100r/min C.4140r/min D.4400r/min
A.50Hz B.60Hz C.75Hz D.140Hz
A.0.1mm B.0.2mm C.0.3mm D.0.4mm
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