Mary：Hello, I have got a few fake one-hundred yuan bills. My friend said I could come here to replace them.
Clerk：Yes, you should come here. Show me the bills, please.
Mary：Here they are. I found out they were counterfeit when I paid for some things at the market.
Clerk：Well，they will be kept by the bank; but I am afraid they will not replaced.
Mary：I see. If there are millions of people who come to replace fake bills, banks will go bankrupt.
Clerk：Yes, I am sorry for your loss, the only compensation we can give you is to ask one of our staff members to teach you how to distinguish fake bills from real ones.
Mary：OK. That will help me a lot.