[填空题]Birds with avian flu often have a mortality rate approaching 100%.

[填空题]Birds with avian flu often have a mortality rate approaching 100%.

[单项选择]　8 New York Students Have Swine Flu 　　The Centers for Disease Control and Prevention has confirmed 51 of swine flu in eight students at a New York preparatory school, Mayor Michael Bloomberg said Sunday. The students have had only 52 symptoms and none have been hospitalized, he said. Some of the students have already recovered. 　　More than 100 students were absent from 53 due to flu-like symptoms last week. New York health officials tested samples for eight students Saturday and determined the students were probably 54 from swine flu, and the CDC confirmed the 55 on Sunday, Bloomberg said. 　　The announcement brings the 56 of confirmed swine flu cases in the United States to 20. Bloomberg and New York Health Commissioner Tom Frieden said there is no 57 of a citywide outbreak of the flu, and no sign of a potential 58 of swine flu at other schools. 　　Some students at the school 59 spring break1 in Mexico, Bloomberg said, but authorities have not determined 60 any of the students with
A. cases
B. bases
C. does
D. noses

[单项选择]

The difference between avian flu and human flu that should be commanding our rapt attention today is that avian influenza, specifically the H5N1 strain known as bird flu, threatens to become the young people’s plague. And it is a growing contender to cause a devastating worldwide pandemic in the next few years.
We are too used to thinking of flu as an annual annoyance that kills only the frail and elderly. But that just isn’t the case for H5N1. With a mortality rate of over 50 percent, this bird flu has killed over 110 people, striking the young and able-bodied the hardest. Its victims cluster predominantly among 5-to-30-year-olds, a pattern that has held up in the 34 known to have died from bird flu so far this year.
This vulnerability may stem from the robust and fast-responding immune systems of the young. The victims overreact to the alien virus, triggering a massive immune response called
A. the body loses oxygen and other organs fail
B. a sodden mass of dying tissues
C. the enthusiastic immune systems of the young
D. the overreaction of blood, toxic fluid, and rampaging inflammatory cells