听力原文：W: Oh, it is terrible! Abroad Aero lines Argentina's flight 386. 386 passengers w

ere given prepared food on their way (20)from Buenos Aires to Los Angeles.

M: Then what happened？

W:A few days after arriving in Los Angeles. (19)one passenger died, and 74 others were seriously ill.

M: What is the reason for that？

W: According to Dr. Phillips, it was the highest single outbreak of cholera in the United States this century, and the airline passengers were the victims of this new epidemic of cholera, a disease not seen in Latin America since 1895. they were just a few of the more than one million people affected in the 20th centuries, including at least 10,000 who died in the following three years after 1991.

M: (19)Cholera？ To the best of my understanding, that disease has been dead for some time now.

W: (19)But it has come back. Dr. Phillips says that cholera is by no means the only old infections on the comeback, and it is just one of the major infections that are fighting back fiercely against man's attempts to control them.

M: (19)But what are the reasons for the comeback of so many dead diseases？

W: Phillips says a single reason can't explain why a new disease appears or an old one returns, and usually a combination of factors are involved.

M: What kind of specific factors？

W: In his book Plagues on Our Doorstep Dr. Phillips presents some reasons.

M: What are they？

W: First, (21) international travel and commerce. The cholera abroad flight 386 and mosquitoes living in imported tries are examples of these. Second, (21) technology and industry. For example, the technology in Britain's processing industry was a likely contributor to the emergence of mad cow disease. Third, (21)the breakdown of public health measures. Declining health resources have resulted in the erosion of once highly-valued health service.

M: Well, that's just unbelievable!

(20)

A．An air crash to Los Angeles.

B．A book written by a doctor.

C．A disease on the comeback and its reasons

D．Man's effort to prevent disease.