30. —Why! I ____ get you on the phone.

— We ______ basketball on the playground when you phoned.

A．didn’t; must have been playing

B．didn’t; must be playing

C．couldn’t; must have played

D．couldn’t; must be playing

自助服务区内每台具备存款、取款、转账功能的自助机具都设置（），位置合理、标识醒目，响应及时。