新GRE逻辑阅读练习题精选
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新GRE逻辑阅读练习题
The determination of the sources of copper ore used in the manufacture of copper and bronze artifacts of Bronze Age civilizations would add greatly to our knowledge of cultural contacts and trade in that era. Researchers have 5 analyzed artifacts and ores for their concentrations of elements, but for a variety of reasons, these studies have generally failed to provide evidence of the sources of the copper used in the objects. Elemental composition can vary within the same copper-ore lode, usually because of varying admixtures of 10 other elements, especially iron, lead, zinc, and arsenic. And high concentrations of cobalt or zinc, noticed in some artifacts,appear in a variety of copper-ore sources. Moreover, the processing of ores introduced poorly controlled changes in the concentrations of minor and trace elements in the 15 resulting metal. Some elements evaporate during smelting and roasting; different temperatures and processes produce different degrees of loss. Finally, flux, which is sometimes added during smelting to remove waste material from the ore, could add quantities of elements to the final product.
20 An elemental property that is unchanged through these chemical processes is the isotopic composition of each metallic element in the ore. Isotopic composition, the percentages of the different isotopes of an element in a given sample of the element, is therefore particularly suitable as an 25 indicator of the sources of the ore. Of course, for this purpose it is necessary to find an element whose isotopic composition is more or less constant throughout a given ore body, but varies from one copper ore body to another or,at least, from one geographic region to another.
30 The ideal choice, when isotopic composition is used to investigate the source of copper ore, would seem to be copper itself. It has been shown that small but measurable variations occur naturally in the isotopic composition of copper. However, the variations are large enough only in rare 35 ores; between samples of the common ore minerals of copper, isotopic variations greater than the measurement error have not been found. An alternative choice is lead, which occurs in most copper and bronze artifacts of the Bronze Age in amounts consistent with the lead being derived from the 40 copper ores and possibly from the fluxes. The isotopic composition of lead often varies from one source of common copper ore to another, with variations exceeding the measurement error; and preliminary studies indicate virtually uniform isotopic composition of the lead from a45 single copper-ore source.
While some of the lead found in an artifact may have been introduced from flux or when other metals were added to the copper ore, lead so added in Bronze Age processing would usually have the same isotopic composition as the lead in the copper ore. Lead isotope 50 studies may thus prove useful for interpreting the archaeological record of the Bronze Age.(473 words)
4. The author first mentions the addition of flux during smelting in the last sentence in the last paragraph in order to
(A) give a reason for the failure of elemental composition studies to determine ore sources
(B) illustrate differences between various Bronze Age civilizations
(C) show the need for using high smelting temperatures
(D) illustrate the uniformity of lead isotope composition
(E) explain the success of copper isotope composition analysis For the following question, consider each of the choices separately and select all that apply
5. According to the passage, possible sources of the lead found in a copper or bronze artifact include which of the following?
□A The copper ore used to manufacture the artifact
□B Flux added during processing of the copper ore
□C Other metal added during processing of the copper ore
6. Select the sentence in the passage that the author rejects copper as the "ideal choice".
7. It can be inferred from the passage that the use of flux in processing copper ore can alter the lead isotope composition of the resulting metal EXCEPT when
(A) there is a smaller concentration of lead in the flux than in the copper ore
(B) the concentration of lead in the flux is equivalent to that of the lead in the ore
(C) some of the lead in the flux evaporates during processing
(D) any lead in the flux has the same isotopic composition as the lead in the ore
(E) other metals are added during processing
正确答案:4. A 5. ABC 6. "However, the variations are large enough" 7. D
新GRE逻辑阅读练习题
Traditional research has confronted only Mexican and United States interpretations of Mexican-American culture. Now we must also examine the culture as we Mexican Americans have experienced it, passing from 5 a sovereign people to compatriots with newly arriving settlers to, finally, a conquered people—a charter minority on our own land. When the Spanish first came to Mexico, they inter-married with and absorbed the culture of the indigenous 10 Indians. This policy of colonization through acculturation was continued when Mexico acquired Texas in the early 1800‘s and brought the indigenous Indians into Mexican life and government. In the 1820‘s, United States citizens migrated to Texas, attracted by land suitable for cotton. 15 As their numbers became more substantial, their policy of acquiring land by subduing native populations began to dominate. The two ideologies clashed repeatedly,culminating in a military conflict that led to victory for the United States. Thus, suddenly deprived of our parent 20 culture, we had to evolve uniquely Mexican-American modes of thought and action in order to survive.(168 words)
1. The author‘s purpose in writing this passage is primarily to
(A) suggest the motives behind Mexican and United States intervention in Texas
(B) document certain early objectives of Mexican-American society
(C) provide a historical perspective for a new analysis of Mexican-American culture
(D) appeal to both Mexican and United States scholars to give greater consideration to economic interpretations of history
(E) bring to light previously overlooked research on Mexican Americans
2. The author most probably uses the phrase "charter minority" (lines 6-7) to reinforce the idea that Mexican Americans
(A) are a native rather than an immigrant group in the United States
(B) played an active political role when Texas first became part of the United States
(C) recognized very early in the nineteenth century
the need for official confirmation of their rights of citizenship
(D) have been misunderstood by scholars trying to interpret their culture
(E) identify more closely with their Indian heritage than with their Spanish heritage
3. Which of the following statements most clearly contradicts the information in this passage?
(A) In the early 1800‘s, the Spanish committed more resources to settling California than to developing Texas.
(B) While Texas was under Mexican control, the population of Texas quadrupled, in spite of the fact that Mexico discouraged immigration from the United States.
(C) By the time Mexico acquired Texas, many Indians had already married people of Spanish heritage.
(D) Many Mexicans living in Texas returned to Mexico after Texas was annexed by the United States.
(E) Most Indians living in Texas resisted Spanish acculturation and were either killed or enslaved.
正确答案:C/A/E
新GRE逻辑阅读练习题
Until about five years ago, the very idea that peptide hormones might be made anywhere in the brain besides the hypothalamus was astounding. But laboratory after laboratory found that antiserums to peptide hormones, 5 when injected into the brain, bind in places other than the hypothalamus, indicating that either the hormones or substances that cross-react with the antiserums are present.The immunological method of detecting peptide hormones by means of antiserums, however, is 10 imprecise. Cross-reactions are possible and this method cannot determine whether the substances detected by the antiserums really are the hormones, or merely close relatives.
Furthermore, this method cannot be used to determine the location in the body where the detected 15 substances are actually produced. New techniques of molecular biology, however, provide a way to answer these questions. It is possible to make specific complementary DNA‘s (cDNA‘s) that can serve as molecular probes to seek out the messenger RNA‘s 20 (mRNA‘s) of the peptide hormones. The brain cells containing these mRNA‘s can then be isolated and their mRNA‘s decoded to determine just what their protein products are and how closely the products resemble the true peptide hormones.
(187 words)
11. Which of the following titles best summarizes the passage?
(A) Is Molecular Biology the Key to Understanding Intercellular Communication in the Brain?
(B) Molecular Biology: Can Researchers Exploit Its Techniques to Synthesize Peptide Hormones?
(C) The Advantages and Disadvantages of the Immunological Approach to Detecting Peptide Hormones
(D) Peptide Hormones: How Scientists Are Attempting to Solve Problems of Their Detection
(E) Peptide Hormones: The Role Played by Messenger RNA‘s in Their Detection
12. The passage suggests that a substance detected in the brain by use of antiserums to peptide hormones may
(A) have been stored in the brain for a long period of time
(B) play no role in the functioning of the brain
(C) have been produced in some part of the body other than the brain
(D) have escaped detection by molecular methods
(E) play an important role in the functioning of the hypothalamus
13. Which of the following is mentioned in the passage as a drawback of the immunological method of detecting peptide hormones?
(A) It cannot be used to detect the presence of growth regulators in the brain.
(B) It cannot distinguish between the peptide hormones and substances that are very similar to them.
(C) It uses antiserums that are unable to cross the blood-brain barrier.
(D) It involves a purification process that requires extensive training in endocrinology.
(E) It involves injecting foreign substances directly into the bloodstream.
答案:D/C/B
新GRE逻辑阅读练习题
Biologists have long maintained that two groups of pinnipeds, sea lions and walruses, are descended from a terrestrial bearlike animal, whereas the remaining group, seals, shares an ancestor with weasels. But the 5 recent discovery of detailed similarities in the skeletal structure of the flippers in all three groups undermines the attempt to explain away superficial resemblance as due to convergent evolution—the independent develop-ment of similarities between unrelated groups in 10 response to similar environmental pressures. Flippers may indeed be a necessary response to aquatic life,turtles, whales, and dugongs also have them. But the common detailed design found among the pinnipeds probably indicates a common ancestor. Moreover,15 walruses and seals drive themselves through the water with thrusts of their hind flippers, but sea lions use their front flippers. If anatomical similarity in the flippers resulted from similar environmental pressures, as posited by the convergent-evolution theory, one 20 would expect walruses and seals, but not seals and sea lions, to have similar flippers.(162 words)
1. The author implies that which of the following was part of the long-standing view concerning pinnipeds?
□A Pinnipeds are all descended from a terrestrial bearlike animal.
□B Pinnipeds share a common ancestor with turtles,whales, and dugongs
□C Similarities among pinnipeds are due to their all having had to adapt to aquatic life.
2. The author implies which of the following about the fact that turtles, whales, and dugongs all have flippers?
○A It can be explained by the hypothesis that turtles,whales, and dugongs are very closely related.
○B It can be explained by the idea of convergent evolution.
○C It suggests that turtles, whales, and dugongs evolved in separate parts of the world
○D It undermines the view that turtles, whales, and dugongs are all descended from terrestrial ancestors.
○E It is the primary difference between turtles, whales,and dugongs, on the one hand, and pinnipeds, on the other.
3. Select the sentence in the passage in which the author shows that the implication of the common view is contradicted by a new finding.
答案:C/ B /But the common detailed design found among the pinnipeds probably indicates a common ancestor