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沙发
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发表于 2012-8-1 23:44:52
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【Here is explanation for reference】
Question Type: Assumption Each year’s vaccination will protect only against the strain of the virus deemed most likely to be prevalent that year, so high-risk individuals will need to receive a vaccine for a different strain each year. Doesn’t this assume that the prevalent strain of the virus will change every year? Take, for example, a hypothetical scenario in which last year’s prevalent flu strain was the same as this year’s. High-risk individuals would thus be getting the same vaccination this year that they got last year. In order to conclude that people will get vaccinated for a different strain each year, the author must assume that the flu strain will change each year. Answer (D) correctly expresses this assumption. (A) is out of scope. The number of vaccinations given is not at issue. (B) is out of scope. The likelihood of an outbreak is irrelevant. (C) is tempting, but notice the language in the passage: the annual vaccination will protect against just one strain – the one deemed most likely to be prevalent that year. Thus, the fact that no vaccine protects against multiple strains is a moot point. (E) is out of scope (side effects?). |
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