运用流水作业法组织施工,对整个施工过程的进度起控制作用的流水作业有()。
A.分项工程流水作业
B.分部工程流水作业
C.单位工程流水作业
D.工程项目流水作业
参考答案:A
—Your colleague is speaking English with fluency.
—It's no wonder.She ____ in the UK for a year as a visiting professor
A.worked
B.has worked
C.had worked
D.has been working
不同地区的PM2.5浓度及组成有什么差别?