以下哪一条不是产生未焊透的原因() A.焊接电流过大 B.坡口钝边过大 C.组间间隙 发布时间:2018-01-29 04:30 │ 来源:www.tikuol.com 题型:单项选择题 问题: 以下哪一条不是产生未焊透的原因()A.焊接电流过大B.坡口钝边过大C.组间间隙过小D.焊根清理不好
题型:单项选择题 —Why do you look so worried? —Fred left the company half an hour ago. His work _______ unfinished since.A.leftB.was left C.has leftD.has been left 查看答案