— Hello, is Billy in? 

— Sorry, he isn't in, ____[ ]

A. Billy, here is a call for you.

B. can you take a message?

C. go ahead, I'll give him a message.

D. Billy, get the call.

ZJ-7型空气制动机自阀手柄在过充位时，列车管过充量为30-40kpa。