单项选择题
A.10 B.20 C.50 D.100
A.红 B.黄 C.蓝 D.绿
A.18.5mm±1.5mm B.17.5mm±1.5mm C.18.5mm±2.5mm D.17.5mm±2.5mm
A.1% B.2% C.5% D.10%
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