A、Teacher and student. B、Husband and wife. C、Doctor and patient. D、Shop assistant and customer. C本题的问题关键词是relationship。对话中提到感冒、

M: How long have you been with your sister?
W: From last October 1st to this May 2nd.
Q: How many months did the man and his sister spend together?

M: Good morning, Mrs. Waller. What’s the problem?
W: I’ve got a heavy cold and now it’s turned into a bad cough.
Q: What’s the possible relationship between the two speakers?