--- Hi, Kate, can I use your bike for a while this afternoon?

--- Sorry.??__________?.

A．It’ s repaired?

B．It has been repaired

C．It’s being repaired?

D．It had been repaired

刮板输送机是煤炭的承载机构，其牵引推动机构是绕过机头链轮和机尾链轮（也有采用带有过链沟槽的滚筒）而进行循环运动的无极闭合的刮板链。