单项选择题
A.5.0mm B.2.5mm C.4.75mm D.2.36mm
A.20±1℃ B.20±2℃ C.20±3℃ D.20±5℃
A.10% B.15% C.20% D.25%
A.1:3,1.0 B.1:4,0.5 C.1:3,0.5 D.1:4,1.0
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