焊接与切割1949年，北京已有气焊、电弧焊及氧乙炔火焰切割等手工作业。
Welding and cutting in 1949, Beijing has geo-drilling, electric welding and cutting etc oxyacetylene flame manual operation.
焊接与切割1949年，北京已有气焊、电弧焊及氧乙炔火焰切割等手工作业。
Welding and cutting in 1949, Beijing has geo-drilling, electric welding and cutting etc oxyacetylene flame manual operation.
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