An accident ______ happen in the street 发布时间:2017-06-06 18:21 │ 来源:www.tikuol.com 题型:选择题 问题: An accident ______ happen in the street a week ago. [ ]A. does B. did C. do D. had to
题型:选择题 某机械制造厂热处理车间气温高达4℃~50℃,单向热辐射强度达41.8~62.8J/cm·min,对上述生产环境首先考虑采取的防暑降温措施是()A.合理布置热源B.全面自然通风C.局部自然通风D.机械通风E.隔热 查看答案