钢结构支撑时,应严格材料检验,不得在()下进行焊接。
A.非标准状态
B.负载状态
C.危险状态
D.不合格状态
参考答案:B
下列物质属于纯净物的是( )
A.漂白粉
B.大理石
C.液氯
D.盐酸
—Are you free after school?
—worry, I’ve planned to treat a friend of mine to dinner ____ for help. [ ]
A. in order
B. in return
C. in turn
D. in honor