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  3. Although we already know a great deal about influenza, it is difficult for epidemiologists(流行病学家), who study infectious disease,

Although we already know a great deal about influenza, it is difficult for epidemiologists(流行病学家), who study infectious disease,

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问题     Although we already know a great deal about influenza, it is difficult for epidemiologists(流行病学家), who study infectious disease, to【C1】______when and where the next flu epidemic will occur, and how【C2】______it will be. There are three kinds of influenza virus, known as A, B and C. Influenza C virus is relatively stable and causes mild【C3】______that do not spread far through the population. The A and B types are【C4】______, and are responsible for the epidemics that cause frequent concern. Following any virus attack, the human body builds up antibodies which confer(给予)immunity to that strain of virus, but a virus with the capacity to change its character is able to bypass this【C5】______. Variability is less developed in the influenza B virus, which affects only human beings. An influenza B virus may cause a widespread epidemic but will have little effect if【C6】______into the same community soon afterwards, since nearly everyone will have built up antibodies and will be immune. The influenza A virus, which【C7】______affects animals, is extremely unstable and is responsible for some of the worst outbreaks of the disease, such as the unparalleled pandemic, or world epidemic. Accurate prediction is difficult because of the complication of the【C8】______. A particular virus may be related to one to which some of the population have【C9】______involved immunity. The extent to which it will spread will depend on factors such as its own strength, or virulence, the ease with which it can be【C10】______and the strength of the opposition it encounters. Scientists, however, have a reliable general picture of the world situation, according to which we may take some precautions.
A)partially I)epidemics
B)guess J)also
C)factors K)attacks
D)equally L)introduced
E)generally M)unstable
F)protection N)infections
G)transmitted 0)predict
H)severe
【C7】
选项
答案J
解析 此处应填副词。定语从句中结构完整，应填副词。可选项有D)equally和J)also，前面提到乙型流感病毒只感染人类，此处说明的是甲型流感病毒除了像乙型流感病毒一样会感染人类以外，还感染动物，没有对两种感染性在程度上进行比较，故排除D)equally,选J)also。
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