单项选择题
A.1/2 B.1/3 C.1/4 D.1/5
A.40mm B.60mm C.80mm D.100mm
A.±0.1% B.±0.5% C.±1% D.±2%
A.2~2.0 B.2.2-3.0 C.2.6~3.4 D.3.0~3.8
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