单项选择题
A.0.5 B.2 C.4 D.8
A.1/2100 B.1/3500 C.0.009 D.1/211200
A.100m±0.025m B.250m±0.060m C.150m±0.035m D.200m±0.036m
A.±3.6〞 B.±4.2〞 C.±7.2〞 D.±3.8〞
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