— Is your sister a League member?

—Yes, She ___ the League two years ago. She ____ a League member for two years.

A．has joined; has been

B．joined; was

C．joined; has been

D．joins; was

根据DL5009.1—2014《电力建设安全工作规程第1部分：火力发电》第5.7.1条规定，烟囱施工金属竖井架（）

A.工作平台的允许荷载应经设计确定，并悬挂载荷警示标识

B.工作平台上铺设的木板与横木必须连接牢固，横木与钢圈宜采用抱箍螺栓连接方式，连接应牢固。平台木板厚度应不小于30mm，铺设平整

C.提升工作平台应统一指挥，升降应平稳、均匀

D.罐笼应有安全制动器并定期检验合格，严禁人货混载