CUSTOMER: I bought two expensive dictionaries here half an hour ago, but I forgot to take them with me.
MANAGER: Who served you, sir?
CUSTOMER: The lady who is standing behind the counter.
MANAGER: Which books did you buy?
CUSTOMER: The books which are on the counter.
MANAGER: Did you serve this gentleman half an hour ago, Miss? There's a mistake.
HELEN: What was the mistake?
MANAGER: He says he's the man who bought these books.
HELEN: I can't remember. The man who I served was wearing a hat.
MANAGER: Have you got a hat, sir?
CUSTOMER: Yes, I have.
MANAGER: Would you put it on, please?
CUSTOMER: All right.
MANAGER: Is this the man that you served, Miss?
HELEN: Yes. I recognize him now.