去除坡口两侧和焊丝表面的油、锈和水等污物,气焊熔剂焊前应烘干,以减少焊缝中()的来源 发布时间:2017-05-07 05:19 │ 来源:www.tikuol.com 题型:单项选择题 问题: 去除坡口两侧和焊丝表面的油、锈和水等污物,气焊熔剂焊前应烘干,以减少焊缝中()的来源。A、氮B、氧C、氢D、碳
题型:单项选择题 What does the speaker mean A.He was nearly killed by someone.B.He saw a ghost in the house.C.He was scared out of his wits.D.He saw a man rushing at him. 查看答案