A、The mystery story. B、The hiring of a shop assistant. C、The search for a reliable witness. D、An unsolved case of robbery. D男士问：

W: How did you make out your course? I think it’s not an easy job for me.
M: Not for me really. The only thing I haven’t understood is the reading we did last night.
Q: How was the man doing in the work?

M: You were seen hanging about the store on the night when it was robbed, weren’t you?
W: Me? You must have made a mistake. I was at home that night.
Q: What are they talking about?