A、This morning. B、This afternoon. C、Before lunch. D、After lunch. C两人在电话里最后确定是当天上午11：30，午饭前。

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.
Questions 16-20 are based on the conversation you have just heard:
16. Why did the doctor not come to the phone immediately?
17. What was the matter with Mr. Jackson?
18. How long has Mr. Jackson been suffering?
19. How did the doctor respond to the caller?
20. When would the doctor see Mr. Jackson?