【正确答案】 A

【答案解析】[听力原文]
W: Good morning. Dr. Ellis office.
M: This is Mr. Jackson. May I please speak with the doctor?
W: The doctor is just finishing with a patient. Would you hold on for a minute?
W: Here is the doctor now, I"ll tell him you"re on the line.
D: Mr. Jackson, Dr. Ellis is here. How"s that new bridge?
M: Not so good, doctor. That"s what I"m calling about. It just doesn"t seem to fit right.
D: Well, that"s to be expected during the first few days after it has been put in. As I told you, there will be no complications.
M: It hurts so much, especially when I eat. I keep removing it afterwards, you know.
D: I understand, Mr. Jackson. It does hurt in the beginning, I know. But it would be better if you didn"t remove it, except when cleaning it, of course.
M: Well I did at first, doctor, but my gums hurt so much that I just can"t stand it any longer.
D: Well, maybe we can adjust it a little more.
M: Adjust it?
D: Yes, file it down a little here and there. When can you come in?
M: Oh, right away, doctor, if you don"t mind.
D: Let me see, I"ll check here now, maybe I can find the time for you this morning.
M: Oh, I can wait until this afternoon if you"re too busy now.
D: Sorry, Mr. Jackson, but I"d rather you"d come this morning if possible. This afternoon I"m teaching a class at the dental school. Just a minute. Mr. Jackson, can you get here about 11:30? And that will give us enough time before lunch. We"ll see what we can do.
M: Oh, yes doctor. I can make it. Thank you. See you then.

Why did the doctor not come to the phone immediately?

[解析] 女助手说医生刚刚完成一个病人的手术。要稍等一下。