Passage 20(biology)(一段式文章)
Although genetic mutations(突變) in bacteria and viruses can lead to epidemics(流行性疾病), some epidemics are caused by bacteria and viruses that have undergone no significant genetic change(其實讀完第一句就要知道文章是講,有些傳染病不必由突變產生也會出現,而且後半句較前半段更重要). In analyzing the latter(果然要討論後半段), scientists have discovered the importance of social and ecological factors to epidemics. Poliomyelitis(小兒麻痺), for example, emerged(以傳染病型式在二十世紀的美國出現) as an epidemic in the United States in the twentieth century; by then, modern sanitation was able to delay exposure to polio until adolescence or adulthood, at which time polio infection produced paralysis(癱瘓). Previously, infection had occurred during infancy, when it typically provided lifelong immunity (免疫力) without paralysis(不會癱瘓?). Thus, the hygiene that helped prevent typhoid epidemics(流行性傷寒) indirectly fostered a paralytic polio epidemic.(這整段怪怪的,要再研究一下) Another example is Lyme disease(萊姆病), which is caused by bacteria that are transmitted by deer ticks. It occurred only sporadically(偶發地) during the late nineteenth century but has recently become prevalent in parts of the United States; largely due to an increase in the deer population that occurred simultaneously with the growth of the suburb(郊區) sand increased outdoor recreational activities in the deer’s habitat. Similarly, an outbreak(爆發) of dengue(登革熱) hemorrhagic fever(出血性感冒) became an epidemic in Asia in the 1950’s because of ecological changes that caused Aedes aegypti, the mosquito that transmits the dengue virus, to proliferate(繁殖). The stage is now set in the United States for a dengue epidemic because of the inadvertent(無意的) introduction and wide dissemination(散撥) of another mosquito, Aedes bopictus.
結論及關鍵句就在第一句話,後面只是舉出三個例子證明他的看法,基因改變當然是流行病的主要原因,但很多時候則是社會及生態的變化,但文章必須仔細搞清楚三種狀況的不同差異處
*119. The passage suggests that a lack of modern sanitation would make which of the following most likely to occur?
(A) An outbreak of Lyme disease
(B) An outbreak of dengue hemorrhagic fever
(C) An epidemic of typhoid
(D) An epidemic of paralytic polio among infants
(E) An epidemic of paralytic polio among adolescents and adults
文章暗示,早期小兒麻痺都是傳給小孩,但衛生改善後,都是傳給大人,那麼不衛生的情況下,不就是講小兒麻痺會讓嬰兒感染,當然也會有風寒,但CD該如何挑哩?
答案給C ,請看,Previously, infection had occurred during infancy, when it typically provided lifelong immunity
*120. According to the passage, the outbreak of dengue hemorrhagic fever in the 1950’s occurred for which of the following reasons?(A) The mosquito Aedes aegypti was newly introduced into Asia.
(B) The mosquito Aedes aegypti became more numerous.
(C) The mosquito Aedes albopictus became infected with the dengue virus.
(D) Individuals who would normally acquire immunity to the dengue virus as infants were not infected until later in life.
(E) More people began to visit and inhabit areas in which mosquitoes live and breed.
答案給B,難不成是由to proliferate這個字過來,被迫選B?答案:是的,就是繁殖這個字
121. It can be inferred from the passage that Lyme disease has become prevalent in parts of the United States because of which of the following?
(A) The inadvertent introduction of Lyme disease bacteria to the United States
(B) The inability of modern sanitation methods to eradicate Lyme disease bacteria
(C) A genetic mutation in Lyme disease bacteria that makes them more virulent
(D) The spread of Lyme disease bacteria from infected humans to noninfected humans
(E) An increase in the number of humans who encounter deer ticks
122. Which of the following can most reasonably be concluded about the mosquito Aedes albopictus on the basis of information given in the passage?
(A) It is native to the United States.
(B) It can proliferate only in Asia.
(C) It transmits the dengue virus.
(D) It caused an epidemic of dengue hemorrhagic fever in the 1950’s.
(E) It replaced Aedes aegypti in Asia when ecological changes altered Aedes aegypti’s habitat.
D好像也不賴,但仔細看,是另一種蚊子造成
123. Which of the following best describes the organization of the passage?
(A) A paradox is stated, discussed and left unresolved.
(B) Two opposing explanations are presented, argued, and reconciled.
(C) A theory is proposed and is then followed by descriptions of three experiments that support the theory.
(D) A generalization is stated and is then followed by three instances that support the generalization.
(E) An argument is described and is then followed by three counterexamples that refute the argument.
124. Which of the following, if true, would most strengthen the author’s assertion about the cause of the Lyme disease outbreak in the United States?
(A) The deer population was smaller in the late nineteenth century than in the mid-twentieth century.
(B) Interest in outdoor recreation began to grow in the late nineteenth century.
(C) In recent years the suburbs have stopped growing.
(D) Outdoor recreation enthusiasts routinely take measures to protect themselves against Lyme disease.
(E) Scientists have not yet developed a vaccine that can prevent Lyme disease.