問題詳情

三、閱讀測驗【請依照段落上下文意，選出最適當的答案】Swine Influenza (swine flu) is a respiratory disease of pigs caused by type A influenza virus thatregularly causes outbreaks of influenza in pigs. Swine flu viruses do not usually infect humans, but rare humaninfections have occurred. They can cause high levels of illness in pig herds, but cause few deaths in pigs. Theseviruses can circulate among swine throughout the year, but most outbreaks occur during the late fall and wintermonths, similar to outbreaks in humans.Like influenza viruses in humans and other animals, swine flu viruses change constantly. Pigs can beinfected by avian influenza and human influenza viruses as well as swine influenza viruses. When influenza virusesfrom different species infect pigs, they can re-assort (i.e. swap genes) and new viruses that are a mix of swine,human and/or avian influenza viruses can emerge. Over the years, different variations of swine flu viruses haveemerged. At this time, there are three main influenza A virus subtypes that have been isolated in pigs in theUnited States: H1N1, H1N2, and H3N2.Signs of swine flu in pigs can include fever, depression, coughing (barking), discharge from the nose or eyes,sneezing, breathing difficulties, eye redness or inflammation, and going off feed. Some pigs infected with influenza,however, may show no signs of illness at all. Thankfully, just as there are influenza vaccines for people, there arespecific swine influenza vaccines available for pigs.
41. What might be the author’s primary purpose of writing this passage?
(A) To guarantee that swine flu viruses do not infect humans.
(B) To testify that swine flu is the main cause of pigs’ death in the United States.
(C)To show the urgent need of inventing specific vaccines to save pigs from being infected.
(D) To introduce some basic information about swine flu viruses and how the flu can be prevented.

參考答案

答案：D
難度：簡單0.771429
統計：A(6),B(4),C(10),D(81),E(0)

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