单项选择题
A.2.3‰ B.3.3‰ C.3.5‰ D.4‰
A.同标准值 B.1‰ C.1.5‰ D.2‰
A.500m B.1000m C.1500m D.2000m
A.6200mm B.6330mm C.6500mm D.6683mm
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