A: What time is this meeting supposed to begin？B: I' m not sure. I thought it was to start

A: What time is this meeting supposed to begin？

B: I' m not sure. I thought it was to start at 7:00 p. m. , but it’s already 7: 20 p. m. .

A: ______

B: It’s unlikely that the guest speaker has arrived yet. I think he is still eating his dinner.

A; Well, that explains it!

A．What do you think the problem is？

B．Don't you know？

C．Are you sure？

D．What do we do then？