单选题听下面一段对话，回答第18至第21题。

单选题 What's the relationship between the speakers?
A. Employer and employee.
B. Teacher and student.
C. Customer and assistant.
D. Police and criminal.

【正确答案】 D

【答案解析】[解析] 18-21
W: Mr. Parker, when did you arrive home yesterday evening?
M: At about 8 o'clock.
W: What did you do right after you entered your flat?
M: Well, I washed my hands and then watched sports news.
W: When did you have supper?
M: At about a quarter to nine, I guess.
W: Did you stay at home all evening?
M: Yes.
W: But your friend said that he called you several times between 8 and 9. But you didn't answer.
M: Well, I think I was in the bath at that time.
W: No, you weren't. You were not even at home last night. You robbed a bank in James Street.

[解析] 本题为推断题。从盘问性对话以及最后一句女士揭穿男士的谎言可知，双方是警察和罪犯的关系，故选D。

单选题 According to the man, what did he first do after he got home?
A. He washed his hands.
B. He had his dinner.
C. He took a shower.
D. He watched sports news.

【正确答案】 A

【答案解析】[解析] 本题为细节题。从男士的回答中可知，他一回到公寓便洗手，然后是观看体育新闻，故选A。

单选题 What place had the man actually been to the night before?
A. A bank. B. A restaurant.
C. A friend's home. D. A shop.

【正确答案】 A

【答案解析】[解析] 本题为推断题，从整个对话宏观上分析，该对话是警察与嫌疑人之间的谈话，在对话结尾之处，警察指出了男士供认中的破绽，一针见血地点出他那天晚上在James Street的一家银行实施了抢劫。故选A。

单选题 What does the man try to do in the conversation?
A. To hide the truth. B. To find the truth.
C. To prove the truth. D. To know the truth.

【正确答案】 A

【答案解析】[解析] 本题为推断题。男士作为嫌疑人，在对话中处处隐瞒事实。