It is good news to us that we are invited to such a great concert, _____?

[      ]

A. is it

B. isn't it

C. are we

D. aren't we

起吊钢筋或钢筋骨架时，下方禁止站人，待钢筋骨架降落至离楼地面或安装标高1m以内人员方准靠近操作，待就位放稳或支撑好后，方可挂钩。