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There is no vaccine to prevent dengue and no specific medicine to treat it, so the only defense is eradication of the mosquitoes that carry it and measures to protect people from mosquito bites. The small white animals with pink eyes are kept in a special isolated room so that they will not be exposed to any bacteria or germs that might infect them. They have been altered to be susceptible to human diseases. By infecting these humanized mice with strains of the dengue virus, investigators can study how the disease takes hold and what factors might cause the more serious and often deadly dengue hemorrhagic fever. Lab workers infect the mice artificially with the virus, keeping precise records of how much virus and what type of virus is used. But natural transmission of dengue by mosquitoes involves certain proteins the insects inject into the skin, something that Rico-Hesse says is missing when mice are artificially infected in the lab. Rico-Hesse and her colleagues are breeding mosquitoes in the laboratory to test various strains of the dengue virus transmitted to the mice by mosquitoes. 1.Which statement is correct according to Paragraph 1 B.Strong effect of certain medication can cure dengue fever. D.Scientists have invented a vaccine that can prevent dengue fever 解析:问题问的是：根据第一段，正确的是哪一项?第一段中提到，没有疫苗和药物能预防或治愈登革热，只有消灭所有携带病毒的蚊子才能防止被感染。由此可见，C选项正确 A.have red eyes. C.are put in the room with lots of mosquitoes. 正确答案:D 3.According to the report, the virus strains that cause the more severe dengue and hemorrhagic fever are actually B.from a special mosquito. D.killable with a specific genetic variant 解析:问题问的是：能够导致更加严重的登革热和出血热的病毒株实际上是什么?第六段最后一句中提到这两种病毒株其实是属于同一种基因变异体。因此选A。容易引起混淆的是D选项，其中提到了特殊变异体，只是该选项的意思是说病毒可以被病毒的特殊变异体杀死，显然不对。注意killable，是kill和able组成的合成词，意为可杀死的 A.Lab workers inject into the mice the fever virus with a syringe . C.The artificial infection of virus has exactly the same effect as the natural one. 正确答案:A 5.What is the authors attitude to the future of the researchers work B.Pessimistic. D.Sarcastic | 
