1、GMAT考試閱讀題GMAT閱讀新題練習(xí)一Although genetic mutations in bacteria and viruses can lead to epidemics, some epidemics are caused by bacteria and viruses that have undergone no significant genetic change. In analyzing the latter, scientists have discovered the importance of social and ecological factors to ep

2、idemics. Poliomyelitis (poliomyelitis: n.小兒麻痹癥, 急性骨髓灰白質(zhì)炎), for example, emerged as an epidemic in the United States in the twentieth century; by then (by then: 到那時(shí)候), modern sanitation was able to delay exposure to polio (POLIOMYELITIS) until adolescence or adulthood, at which time polio infection p

3、roduced paralysis. Previously, infection had occurred during infancy, when it typically provided lifelong immunity without paralysis. Thus, the hygiene that helped prevent typhoid epidemics indirectly fostered a paralytic polio epidemic. Another example is Lyme disease, which is caused by bacteria t

4、hat are transmitted by deer ticks. It occurred only sporadically 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 suburbs and increased outdoor rec

5、reational activities in the deers habitat. Similarly, an outbreak of dengue hemorrhagic fever became an epidemic in Asia in the 1950s because of ecological changes that caused Aedes aegypti, the mosquito that transmits the dengue virus, to proliferate. The stage is now set in the United States for a

6、 dengue epidemic because of the inadvertent introduction and wide dissemination of another mosquito, Aedes albopictus.1. 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 f

7、ever(C) An epidemic of typhoid(D) An epidemic of paralytic polio among infants(C)(E) An epidemic of paralytic polio among adolescents and adults2. According to the passage, the outbreak of dengue hemorrhagic fever in the 1950s occurred for which of the following reasons?(A) The mosquito Aedes aegypt

8、i 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.(B)(E) More people beg

9、an to visit and inhabit areas in which mosquitoes live and breed.3. 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 inabili

10、ty 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)(E) An increase in the number of humans who encounter deer ticks4. Which

11、 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

12、 the 1950s.(C)(E) It replaced Aedes aegypti in Asia when ecological changes altered Aedes aegyptis habitat.5. 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 reconcil

13、ed.(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.(D)(E) An argument is described and is then followed by three counterexamples that refu

14、te the argument.6. Which of the following, if true, would most strengthen the authors 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 be

15、gan 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.(A)(E) Scientists have not yet developed a vaccine that can prevent Lyme disease.GMAT閱讀新題練習(xí)二It was onc

16、e assumed that all living things could be divided into two fundamental and exhaustive categories. Multicellular plants and animals, as well as many unicellular organisms, are eukaryotictheir large, complex cells have a well-formed nucleus and many organelles. On the other hand, the true bacteria are

17、 prokaryotic cell (prokaryotic cell: 原核細(xì)胞), which are simple and lack a nucleus. The distinction between eukaryotes and bacteria, initially defined in terms of subcellular structures visible with a microscope, was ultimately carried to the molecular level. Here prokaryotic and eukaryotic cells have

18、many features in common. For instance, they translate genetic information into proteins according to the same type of genetic coding. But even where the molecular processes are the same, the details in the two forms are different and characteristic of the respective forms. For example, the amino aci

19、d sequences of various enzymes tend to be typically prokaryotic or eukaryotic. The differences between the groups and the similarities within each group made it seem certain to most biologists that the tree of life had only two stems. Moreover, arguments pointing out the extent of both structural an

20、d functional differences between eukaryotes and true bacteria convinced many biologists that the precursors of the eukaryotes must have diverged from the common ancestor before the bacteria arose.Although much of this picture has been sustained by more recent research, it seems fundamentally wrong i

21、n one respect. Among the bacteria, there are organisms that are significantly different both from the cells of eukaryotes and from the true bacteria, and it now appears that there are three stems in the tree of life. New techniques for determining the molecular sequence of the RNA of organisms have

22、produced evolutionary information about the degree to which organisms are related, the time since they diverged from a common ancestor, and the reconstruction of ancestral versions of genes. These techniques have strongly suggested that although the true bacteria indeed form a large coherent group,

23、certain other bacteria, the archaebacteria (archaebacteria: 復(fù) n.微原始細(xì)菌( 一種不同于細(xì)菌和動(dòng)植物細(xì)胞且要求完全厭氧條件并能產(chǎn)生甲烷的微生物), which are also prokaryotes and which resemble true bacteria, represent a distinct evolutionary branch that far antedates the common ancestor of all true bacteria.1. The passage is primarily conc

24、erned with(A) detailing the evidence that has led most biologists to replace the trichotomous picture of living organisms with a dichotomous one(B) outlining the factors that have contributed to the current hypothesis concerning the number of basic categories of living organisms(C) evaluating experi

25、ments that have resulted in proof that the prokaryotes are more ancient than had been expected(D) summarizing the differences in structure and function found among true bacteria, archaebacteria, and eukaryotes(B)(E) formulating a hypothesis about the mechanisms of evolution that resulted in the ance

26、stors of the prokaryotes2. According to the passage, investigations of eukaryotic and prokaryotic cells at the molecular level supported the conclusion that(A) most eukaryotic organisms are unicellular(B) complex cells have well-formed nuclei(C) prokaryotes and eukaryotes form two fundamental catego

27、ries(D) subcellular structures are visible with a microscope(C)(E) prokaryotic and eukaryotic cells have similar enzymes3. According to the passage, which of the following statements about the two-category hypothesis is likely to be true?(A) It is promising because it explains the presence of true b

28、acteria-like organisms such as organelles in eukaryotic cells.(B) It is promising because it explains why eukaryotic cells, unlike prokaryotic cells, tend to form multicellular organisms.(C) It is flawed because it fails to account for the great variety among eukaryotic organisms.(D) It is flawed be

29、cause it fails to account for the similarity between prokaryotes and eukaryotes.(E)(E) It is flawed because it fails to recognize an important distinction among prokaryotes.4. It can be inferred from the passage that which of the following have recently been compared in order to clarify the fundamen

30、tal classifications of living things?(A) The genetic coding in true bacteria and that in other prokaryotes(B) The organelle structures of archaebacteria, true bacteria, and eukaryotes(C) The cellular structures of multicellular organisms and unicellular organisms(D) The molecular sequences in eukary

31、otic RNA, true bacterial RNA, and archaebacterial RNA(D)(E) The amino acid sequences in enzymes of various eukaryotic species and those of enzymes in archaebacterial species5. If the “new techniques” mentioned in line 31 were applied in studies of biological classifications other than bacteria, whic

32、h of the following is most likely?(A) Some of those classifications will have to be reevaluated.(B) Many species of bacteria will be reclassified.(C) It will be determined that there are four main categories of living things rather than three.(D) It will be found that true bacteria are much older than eukaryotes.(A)(E) It will be found that there is a common ancestor of the eukaryotes, archaebacteria, and true bacteria.6. Accordi