The great influenza epidemic ____ over 20 million dead.

A.left about

B.left behind

C.left for

D.left down

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发布时间：2022-12-05

更多“The great influenza epidemic ____ over 20 million dead.”相关的问题

第1题

Influenza或SARS病毒的什么性质使得研制相应的疫苗十分困难？（)A．DNA复制缺乏校对使得抗原基

Influenza或SARS病毒的什么性质使得研制相应的疫苗十分困难？()

A．DNA复制缺乏校对使得抗原基因容易突变

B．RNA复制缺乏校对使得抗原基因容易突变

C．DNA转录缺乏校对使得抗原基因容易突变

D．基因组过大，超过100 kb

E．基因组不稳定，容易被水解

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第2题

Influenza is a viral infection. The flu 26____which caused the 1918

27____was 25 times more deadly than normal and it caused more deaths than the First World War.

The consequences of a massive 28____could be disastrous for 29____.For example, a cloud of ash could 30_the sun and the molten lava would destroy everything in its path.

26. A. virus B. chemical C. epidemic D. wave

27. A. impact B. disaster C. pandemic D. eruption

28. A. forest fire B. tsunami C. greenhouse gas D. volcanic eruption

29. A. terrorists B. scientists C. humanity D. mass migration

30. A. block out B. head for C. put out D. wipe out

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第3题

The timing of flu season is a little hard to predict. Part of what makes it unpredictable

is that scientists still don t understand exactly why we have one at all. There have been lots of theories: One theory is that people spend more time indoors, with the windows closed, breathing each other s air. Other scientists have argued that cold of winter weakens our immune systems. A third theory is that the flu virus lives in the cold, dry air, but suffers in the warm, humid air. For a while, scientists had a hard time testing these theories: they needed to run experiments, but researchers aren t allowed to infect humans with illnesses, and most lab animals arent affected by the flu the same way people are. In 2007, a medical researcher named Peter Palese found an 80-year-old journal article that reported that guinea pigs (豚鼠)get infected and pass on the flu just like humans. Palese decided to test Theory 3. The research team led by Palese ran several experiments and in each experiment, they injected half the guinea pigs with influenza A (the common flu), and put them in a box next to a box of uninfected animals. At a temperature of 41 degrees, all four of the exposed guinea pigs caught the flu, but when Palese repeated the experiment at 68 degrees, only one of the animals was infected. And when he ran the test at 86 degrees, none of the exposed animals got sick. The researchers also ran experiments where they varied the humidity in the room but kept the temperature constant: the drier the air, they found, the more animals got sick. Palese s study showed that the influenza virus does spread more effectively in cold, dry air.

What does Paragraph 3 mainly discuss？

A．The direction for future research.

B．The necessity of running more tests.

C．The difficulty of testing the theories.

D．The cost of animal experiments.

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第4题

____ the houses were knocked down in the earthquake.

A.The number of

B.A great many of

C.A great deal of

D.A great many