Longitudinal direction butt joint of gthin gas - in tube on No. 9 helicopter has been welded by use of microplasma arc improved , and results are comfortable.是什么意思_Longitudinal direction butt joint of gthin gas - in tube on No. 9 helicopter has been welded by use of microplasma arc improved , and results are comfortable.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句