1、GMAT( VERBAL)阅读练习试卷 2及答案与解析 1 Nearly a century ago, biologists found that if they separated an invertebrate animal embryo into two parts at an early stage of its life, it would survive and develop as two normal embryos. This led them to believe that the (5) cells in the early embryo are undetermined
2、 in the sense that each cell has the potential to develop in a variety of different ways. Later biologists found that the situation was not so simple. It matters in which plane the embryo is cut. If it is cut in a plane different from the one used (10) by the early investigators, it will not form tw
3、o whole embryos. A debate arose over what exactly was happening. Which embryo cells are determined, just when do they- become irreversibly committed to their fates, and what (15) are the “morphogenetic determinants” that tell a cell what to become? But the debate could not be resolved because no one
4、 was able to ask the crucial questions in a form in which they could be pursued productively. Recent discoveries in molecular biology, however, have (20) opened up prospects for a resolution of the debate. Now investigators think they know at least some of the molecules that act as morphogenetic det
5、erminants in early development. They have been able o show that, in a sense, cell determination begins even before an egg (25) is fertilized. Studying sea urchins, biologist Paul Gross found that an unfertilized egg contains substances that func- tion as morphogenetic determinants. They are located
6、in the cytoplasm of the egg cell; i.e., in that part of the (30) cells protoplasm that lies outside of the nucleus. In the unfertilized egg, the substances are inactive and are not distributed homogeneously. When the egg is fertilized, the substances become active and, presumably, govern the behavio
7、r of the genes they interact with. Since the (35) substances are unevenly distributed in the egg, when the fertilized egg divides, the resulting cells are different from the start and so can be qualitatively different in their own gene activity. The substances that Gross studied are maternal (40) me
8、ssenger RNAs -products of certain of the maternal genes. He and other biologists studying a wide variety of organisms have found that these particular RNAs direct, in large part, the synthesis of histones, a class of proteins that bind to DNA. Once synthesized, the (45) histones move into the cell n
9、ucleus, where section of DNA wrap around them to form a structure that resem- bles beads, or knots, on a string. The beads are DNA segments wrapped around the histones; the string is the intervening DNA. And it is the structure of these beaded (50) DNA strings that guides the fate of the cells in wh
10、ich they are located. 1 It can be inferred from the passage that the morphogenetic determinants present in the early embryo are_ ( A) located in the nucleus of the embryo cells ( B) evenly distributed unless the embryo is not developing normally ( C) inactive until the embryo cells become irreversib
11、ly committed to their final function ( D) identical to those that were already present in the unfertilized egg ( E) present in larger quantities than is necessary for the development of a single individual 2 The main topic of the passage is_ ( A) the early development of embryos of lower marine orga
12、nisms ( B) the main contribution of modern embryology to molecular biology ( C) the role of molecular biology in disproving older theories of embryonic development ( D) cell determination as an issue in the study of embryonic development ( E) scientific dogma as a factor in the recent debate over th
13、e value of molecular biology 3 According to the passage, when biologists believed that the cells in the early embryo were undetermined, they made which of the following mistakes? ( A) They did not attempt to replicate the original experiment of separating an embryo into two parts. ( B) They did not
14、realize that there was a connection between the issue of cell determination and the outcome of the separation experiment. ( C) They assumed that the results of experiments on embryos did not depend on the particular animal species used for such experiments. ( D) They assumed that it was crucial to p
15、erform the separation experiment at an early stage in the embryos life. ( E) They assumed that different ways of separating an embryo into two parts would be equivalent as far as the fate of the two parts was concerned. 4 It can be inferred from the passage that the initial production of histones af
16、ter an egg is fertilized takes place_ ( A) in the cytoplasm ( B) in the maternal genes ( C) throughout the protoplasm ( D) in the beaded portions of the DNA strings ( E) in certain sections of the cell nucleus 5 It can be inferred from the passage that which of the following is dependent on the fert
17、ilization of an egg? ( A) Copying of maternal genes to produce maternal messenger RNAs ( B) Sythesis of proteins called histones ( C) Division of a cell into its nucleus and the cytoplasm ( D) Determination of the egg cells potential for division ( E) Generation of all of a cells morphogenetic deter
18、minants 6 According to the passage, the morphogenetic determinants present in the unfertilized egg cell are which of the following? ( A) Proteins bound to the nucleus ( B) Histones ( C) Maternal messenger RNAs ( D) Cytoplasm ( E) Nonbeaded intervening DNA 7 In the two decades between 1910 and 1930,
19、over ten percent to the Black population of the United States left the South, where the preponderance of the Black population had been located, and migrated to northern (5) states, with the largest number moving, it is claimed, between 1916 and 1918. It has been frequently assumed, but not proved, t
20、hat the majority of the migrants in what has come to be called the Great Migration came from rural areas and were motivated by two concurrent (10) factors: the collapse of the cotton industry following the boll weevil infestation, which began in 1898, and increased demand in the North for labor foll
21、owing the cessation of European immigration caused by the outbreak of the First World War in 1914. This assump- (15) tion has led to the conclusion that the migrants subse- quent lack of economic mobility in the North is tied to rural background, a background that implies unfamil- iarity with urban
22、living and a lack of industrial skills. But the question of who actually left the South has (20) never been rigorously investigated. Although numerous investigations document an exodus from rural southern areas to southern cities prior to the Great Migration. no one has considered whether the same m
23、igrants then moved on to northern cities. In 1910 over 600,000 (25) Black workers, or ten percent of the Black work force, reported themselves to be engaged in “manufacturing and mechanical pursuits,” the federal census category roughly encompassing the entire industrial sector. The Great Migration
24、could easily have been made up entirely (30) of this group and their families. It is perhaps surprising to argue that an employed population could be enticed to move, but an explanation lies in the labor conditions then prevalent in the South. About thirty-five percent of the urban Black popu- (35)
25、lation in the South was engaged in skilled trades. Some were from the old artisan class of slavery-blacksmiths. masons, carpenters-which had had a monopoly of certain trades, but they were gradually being pushed out by competition, mechanization, and obsolescence, (40) The remaining sixty-five perce
26、nt, more recently urban- ized, worked in newly developed industries-tobacco. lumber, coal and iron manufacture, and railroads. Wages in the South, however, were low, and Black workers were aware, through labor recruiters and the (45)Black press, that they could earn more even as unskilled workers in
27、 the North than they could as artisans in the South. After the boll weevil infestation, urban Black workers faced competition from the continuing influx of both Black and White rural workers, who were driven (50) to undercut the wages formerly paid for industrial jobs. Thus, a move north would be se
28、en as advantageous to a group that was already urbanized and steadily employed, and the easy conclusion tying their subse- quent economic problems in the North to their rural background comes into question. 7 The author indicates explicitly that which of the following records has been a source of in
29、formation in her investigation? ( A) United States Immigration Service reports from 1914 to 1930 ( B) Payrolls of southern manufacturing firms between 1910 and 1930 ( C) The volume of cotton exports between 1898 and 1910 ( D) The federal census of 1910 ( E) Advertisements of labor recruiters appeari
30、ng in southern newspapers after 1910 8 In the passage, the author anticipates which of the following as a possible objection to her argument? ( A) It is uncertain how many people actually migrated during the Great Migration. ( B) The eventual economic status of the Great Migration migrants has not b
31、een adequately traced. ( C) It is not likely that people with steady jobs would have reason to move to another area of the country. ( D) It is not true that the term “manufacturing and mechanical pursuits” actually encompasses the entire industrial sector. ( E) Of the Black workers living in souther
32、n cities, only those in a small number of trades were threatened by obsolescence. 9 According to the passage, which of the following is true of wages in southern cities in 1910? ( A) They were being pushed lower as a result of increased competition. ( B) They had begun t to rise so that southern ind
33、ustry could attract rural workers. ( C) They had increased for skilled workers but decreased for unskilled workers. ( D) They had increased in large southern cities but decreased in small southern cities. ( E) They had increased in newly developed industries but decreased in the older trades. 10 The
34、 author cites each of the following as possible influences in a Black workers decision to migrate north in the Great Migration EXCEPT_ ( A) wage levels in northern cities ( B) labor recruiters ( C) competition from rural workers ( D) voting rights in northern states ( E) the Black press 11 It can be
35、 inferred from the passage that the “easy conclusion” mentioned in line 53 is based on which of the following assumptions? ( A) People who migrate from rural areas to large cities usually do so for economic reasons. ( B) Most people who leave rural areas to take jobs in cities return to rural areas
36、as soon as it is financially possible for them to do so. ( C) People with rural backgrounds are less likely to succeed economically in cities than are those with urban backgrounds. ( D) Most people who were once skilled workers are not willing to work as unskilled workers. ( E) People who migrate fr
37、om their birthplaces to other regions of country seldom undertake a second migration. 12 The primary purpose of the passage is to_ ( A) support an alternative to an accepted methodology ( B) present evidence that resolves a contradiction ( C) introduce a recently discovered source of information ( D
38、) challenge a widely accepted explanation ( E) argue that a discarded theory deserves new attention 13 In 1896 a Georgia couple suing for damages in the accidental death of their two year old was told that since the child had made no real economic contribution to the family, there was no liability f
39、or damages. In contrast, (5) less than a century later, in 1979, the parents of a three year old sued in New York for accidental-death damages and won an award of $750,000. The transformation in social values implicit in juxta- posing these two incidents is the subject of Viviana (10) Zelizers excel
40、lent book, Pricing the Priceless Child. During the nineteenth century, she argues, the concept of the “useful” child who contributed to the family economy gave way gradually to the present-day notion of the “useless” child who, though producing no income (15) for, and indeed extremely costly to, its
41、 parents, is yet considered emotionally “priceless.” Well established among segments of the middle and upper classes by the mid-1800s, this new view of childhood spread through- out society in the iate-nineteenth and early-twentieth (20) centuries as reformers introduced child-labor regulations and
42、compulsory education laws predicated in part on the assumption that a childs emotional value made child labor taboo. For Zelizer the origins of this transformation were (25) many and complex. The gradual erosion of childrens productive value in a maturing industrial economy, the decline in birth and
43、 death rates, especially in child mortality, and the development of the companionate family (a family in which members were united by (30) explicit bonds of love rather than duty) were all factors critical in changing the assessment of childrens worth. Yet “expulsion of children from the cash nexus,
44、. although clearly shaped by profound changes in the economic, occupational, and family structures,” Zelizer (35) maintains. “was also part of a cultural process of sacral- ization of childrens lives. ” Protecting children from the crass business world became enormously important for late-nineteenth
45、-century middle-class Americans, she suggests; this sacralization was a way of resisting what (40) they perceived as the relentless corruption of human values by the marketplace. In stressing the cultural determinants of a childs worth. Zelizer takes issue with practitioners of the new “sociological
46、 economics,” who have analyzed such tradi- (45) tionally sociological topics as crime, marriage, educa- tion, and health solely in terms of their economic deter- minants. Allowing only a small role for cultural forces in the form of individual “preferences,” these sociologists tend to view all human
47、 behavior as directed primarily by (50) the principle of maximizing economic gain. Zelizer is highly critical of this approach, and emphasizes instead the opposite phenomenon: the power of social values to transform price. As children became more valuable in emotional terms, she argues, their “excha
48、nge” or “ sur- (55) render” value on the market, that is, the conversion of their intangible worth into cash terms, became much greater. 13 It can be inferred from the passage that accidental-death damage awards in America during the nineteenth century tended to be based principally on the_ ( A) ear
49、nings of the person at time of death ( B) wealth of the party causing the death ( C) degree of culpability of the party causing the death ( D) amount of money that had been spent on the person killed ( E) amount of suffering endured by the family of the person killed 14 It can be inferred from the passage that in the early 1800s children were generally regarded by their families as individuals who_ ( A) needed enormous amounts of security and affection ( B) required constant supervision while working ( C) were important to the economi
copyright@ 2008-2019 麦多课文库(www.mydoc123.com)网站版权所有
备案/许可证编号:苏ICP备17064731号-1