单项选择题
A.1.5mm B.2.0mm C.0.5mm D.2.5mm
A.15mm B.10mm C.16mm D.20mm
A.0.5mm B.0.3mm C.0.1mm D.2.0mm
A.轨底 B.轨腰直至轨底焊缝 C.铝热焊轨头 D.轨腰侧面
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