A.經(jīng)濟(jì)基礎(chǔ) B.物質(zhì)基礎(chǔ) C.生產(chǎn)關(guān)系
A.焊接位置 B.焊接電壓 C.工件傾斜
A.0.5mm B.1.4mm C.1.2mm