A、Mother and son. B、Lawyer and client. C、Teacher and student. D、Dentist and patient. D关键是抓听到能表明双方身份关系的信息，“张大嘴，让我看看哪里痛”和“吃到凉的或是热的

W: Thank heavens! You’re back safe and sound. Everyone was worried on hearing about the air crash. And I had so many sleepless nights!
M: Yes, I know your feeling, dear! Even I myself don’t know how I escaped it. I was the only lucky guy.
Q: What do we learn from the conversation?

W: Open wide. Now show me where it hurts.
M: Here on the bottom, especially when I bite something cold or hot I couldn’t enjoy ice-cream and hot soup any more. It’s a real torture.
Q: What is the most probable relationship between the two speakers?