A、Eating pork. B、Raising pigs. C、Eating chicken. D、Breeding birds. B细节题。题意：什么情况下人会患猪流感?题目是人感染猪流感的原因。根据对话可知，病猪不允许进入市场，烹饪也可杀死病毒。只有

W: Hello doctor Smith, welcome to our program "Health Journey". Could you tell us something about swine flu.
M: Well, it’s a common respiratory ailment in pigs that doesn’t usually spread to people.
W: But why are so many people infected?
M: Unlike most cases, this flu virus appears to be a sub-type not seen before in humans or pigs. It has genetic material from pigs, birds and humans, according to WHO.
W: Then why is it called swine flu? Why pigs are the carriers of this virus?
M: Um. It’s closer to say that pigs were the mixing balls for this virus.
W: What does it mean?
M: I mean birds cannot pass bird flu to people. But pigs are susceptible to getting flu viruses that infected birds. The virus inside the infected pig might mutate to a form that could also infect other mammals.
W: Wow, so complicated. By the way, can we catch swine flu from eating pork?
M: Actually, ill pigs are not allowed to enter the market. Cooking also kills the virus. Only people who work with pigs can catch the virus.
W: How do they feel if infected?
M: The most common symptoms are fever, fatigue, lack of appetite and coughing, although some people also develop runny nose, sore throat, vomiting or diarrhea.
W: What should we do if we have these symptoms?
M: Stay home from work or school. Don’t get on a place. Call your doctors to ask about the best treatment. Don’t simply show up at the clinic or hospital that is unprepared for your arrival.
W: Say, the antiviral study. How is it going?
M: This strain of swine flu does appear sensitive to the antiviral drugs Relenza and Tamiflu, but not to Amantadine and Remantadine.
W: We’ve learned a lot tonight. Thanks for your coming, doctor Smith.
M: It’s my pleasure.
Questions:
16. What do we know about swine flu?
17. What may cause people to have swine flu?
18. According to the dialogue, which is among the most common symptoms of swine flu?
19. What does the speaker advice the suspects of swine flu to do?
20. What can be said of the dialogue?