A、Colleagues. B、Schoolmates. C、Teacher and student. D、Doctor and patient. B对话开头，男士说自他们毕业到现在已经十年了，接着两人谈论了他们最近的工作状况。由此推断，两人以前应该是同学

W: Hello, Tom.
M: Hello, Amy. It has been almost ten years since we graduated.
W: Yeah! Do you still teach in the medical school?
M: No. I worked there three years ago. What about you?
W: I work for the same hospital as ten years ago.
M: I know you are always devoted to what you do.
W: It is very kind of you to say that.
M: I am just telling the truth.
18. What’s the relationship between the man and the woman?
19. Where did the woman work ten years ago?