单项选择题
A.8.74mm B.8.47mm C.8.60mm D.6.50mm
A.6.20mm B.8.60mm C.10.80mm D.11.10mm
A.三根钢丝捻制的钢绞线 B.三根钢丝捻制又经模拨的钢绞线 C.三根刻痕钢丝捻制的钢绞线 D.三根加粗钢丝捻制的钢绞线
A.17.2mm B.9.5mm C.7mm D.1×7mm
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