A、His ID card. B、His business card. C、His receipt. D、His address. C信息明示题。对话中，对于出现问题的手机，男士表示愿意更换新机。女士询问男士是否携带了发票；男士回答说带了，并且递给了女士

W: Mr. Smith, what’s wrong with your smartphone?
M: It wouldn’t give sound when phone calls come in.
W: Have you checked its sound system?
M: Yes, the sound system is OK.
W: When did you buy the smartphone?
M: Three days ago.
W: In that case, you can return it to us or change it for a new one.
M: I want to change it for a new one.
W: OK. Have you brought the receipt with you?
M: Yes, here you are.
17. What has happened to the man’s smartphone?
18. When did the man buy the smartphone?
19. What does the woman ask the man to show?