1、新东方在线 网络课堂电子教材系列 GMAT 阅读讲义1GMAT 阅读讲义主讲：王鹏欢迎使用新东方在线电子教材GMAT 核心阅读Passage 1Caffeine, the stimulant in coffee, has been called“the most widely used psychoactive substance on Earth .”Synder, Daly and Bruns have recently proposed thatcaffeine affects behavior by countering the activity in(5) the human br
2、ain of a naturally occurring chemical calledadenosine. Adenosine normally depresses neuron firingin many areas of the brain. It apparently does this byinhibiting the release of neurotransmitters, chemicalsthat carry nerve impulses from one neuron to the next.(10) Like many other agents that affect n
3、euron firing,adenosine must first bind to specific receptors onneuronal membranes. There are at least two classesof these receptors, which have been designated A1 andA2. Snyder et al propose that caffeine, which is struc-(15) turally similar to adenosine, is able to bind to both typesof receptors, w
4、hich prevents adenosine from attachingthere and allows the neurons to fire more readily thanthey otherwise would.For many years, caffeines effects have been attri-(20) buted to its inhibition of the production of phosphodi-esterase, an enzyme that breaks down the chemicalcalled cyclic AMP.A number o
5、f neurotransmitters exerttheir effects by first increasing cyclic AMP concentra-tions in target neurons. Therefore, prolonged periods at(25) the elevated concentrations, as might be brought aboutby a phosphodiesterase inhibitor, could lead to a greater新东方在线 网络课堂电子教材系列 GMAT 阅读讲义2amount of neuron fir
6、ing and, consequently, to behav-ioral stimulation. But Snyder et al point out that thecaffeine concentrations needed to inhibit the production(30) of phosphodiesterase in the brain are much higher thanthose that produce stimulation. Moreover, other com-pounds that block phosphodiesterases activity a
7、re notstimulants.To buttress their case that caffeine acts instead by pre-(35) venting adenosine binding, Snyder et al compared thestimulatory effects of a series of caffeine derivatives withtheir ability to dislodge adenosine from its receptors inthe brains of mice. “In general,” they reported, “th
8、eability of the compounds to compete at the receptors(40) correlates with their ability to stimulate locomotion inthe mouse; i.e., the higher their capacity to bind at thereceptors, the higher their ability to stimulate locomo-tion.” Theophylline, a close structural relative of caffeineand the major
9、 stimulant in tea, was one of the most(45) effective compounds in both regards.There were some apparent exceptions to the generalcorrelation observed between adenosine-receptor bindingand stimulation. One of these was a compound called3-isobuty1-1-methylxanthine(IBMX), which bound very(50) well but
10、actually depressed mouse locomotion. Snyderet al suggest that this is not a major stumbling block totheir hypothesis. The problem is that the compound hasmixed effects in the brain, a not unusual occurrence withpsychoactive drugs. Even caffeine, which is generally(55) known only for its stimulatory
11、effects, displays thisproperty, depressing mouse locomotion at very lowconcentrations and stimulating it at higher ones.1. The primary purpose of the passage is to(A) discuss a plan for investigation of a phenomenon that is not yet fully understood(B) present two explanations of a phenomenon and rec
12、oncile the differences between them(C) summarize two theories and suggest a third theory that overcomes the problems encountered in the first two(D) describe an alternative hypothesis and provide evidence and arguments that support it(E) challenge the validity of a theory by exposing the inconsisten
13、cies and contradictions in it2. According so Snyder et al, caffeine differs from adenosine in that caffeine(A) stimulates behavior in the mouse and in humans, whereas adenosine stimulates behavior in humans only(B) has mixed effects in the brain, whereas adenosine has only a stimulatory effect新东方在线
14、 网络课堂电子教材系列 GMAT 阅读讲义3(C) increases cyclic AMP concentrations in target neurons, whereas adenosine decreases such concentrations(D) permits release of neurotransmitters when it is bound to adenosine receptors, whereas adenosine inhibits suchrelease(E) inhibits both neuron firing and the production o
15、f phosphodiesterase when there is a sufficient concentration inthe brain, whereas adenosine inhibits only neuron firing3. In response to experimental results concerning IBMX, Snyder et al contended that it is not uncommon forpsychoactive drugs to have(A) mixed effects in the brain(B) inhibitory effe
16、cts on enzymes in the brain(C) close structural relationships with caffeine(D) depressive effects on mouse locomotion(E) the ability to dislodge caffeine from receptors in the brain4. According to Snyder et al, all of the following compounds can bind to specific receptors in the brain EXCEPT(A) IBMX
17、(B) caffeine(C) adenosine(D) theophylline(E) phosphodiesterase5. Snyder et al suggest that caffeines ability to bind to A1 and A2 receptors can be at least partially attributed towhich of the following?(A) The chemical relationship between caffeine and phosphodiesterase(B) The structural relationshi
18、p between caffeine and adenosine(C) The structural similarity between caffeine and neurotransmitters(D) The ability of caffeine to stimulate behavior(E) The natural occurrence of caffeine and adenosine in the brain6. The author quotes Snyder et al in lines 38-43 most probably in order to(A) reveal s
19、ome of the assumptions underlying their theory(B) summarize a major finding of their experiments(C) point out that their experiments were limited to the mouse(D) indicate that their experiments resulted only in general correlations(E) refute the objections made by supporters of the older theory新东方在线
20、 网络课堂电子教材系列 GMAT 阅读讲义4Passage 2Federal efforts to aid minority businesses began in the1960s when the Small Business Administration (SBA)began making federally guaranteed loans and govern-ment-sponsored management and technical assistance(5) available to minority business enterprises. While thisprog
21、ram enabled many minority entrepreneurs toform new businesses, the results were disappointing,since managerial inexperience, unfavorable locations,and capital shortages led to high failure rates. Even 15(10) years after the program was implemented, minoritybusiness receipts were not quite two percen
22、t of the nationaleconomys total receipts.Recently federal policymakers have adopted anapproach intended to accelerate development of the(15) minority business sector by moving away from directlyaiding small minority enterprises and toward supportinglarger, growth-oriented minority firms through inte
23、rme-diary companies. In this approach, large corporationsparticipate in the development of successful and stable(20) minority businesses by making use of government-sponsored venture capital. The capital is used by aparticipating company to establish a Minority EnterpriseSmall Business Investment Co
24、mpany or MESBIC. TheMESBIC then provides capital and guidance to minority(25) businesses that have potential to become future suppliersor customers of the sponsoring company.MESBICs are the result of the belief that providingestablished firms with easier access to relevant manage-ment techniques and
25、 more job-specific experience, as(30) well as substantial amounts of capital, gives those firmsa greater opportunity to develop sound business founda-tions than does simply making general managementexperience and small amounts of capital available.Further, since potential markets for the minority bu
26、si-(35) nesses already exist through the sponsoring companies,the minority businesses face considerably less risk interms of location and market fluctuation. Followingearly financial and operating problems, sponsoringcorporations began to capitalize MESBICs far above(40) the legal minimum of $500,00
27、0 in order to generatesufficient income and to sustain the quality of manage-ment needed. MESBICc are now emerging as increas-新东方在线 网络课堂电子教材系列 GMAT 阅读讲义5ingly important financing sources for minority enter-prises.(45) Ironically, MESBIC staffs, which usually consist ofHispanic and Black professiona
28、ls, tend to approachinvestments in minority firms more pragmatically thando many MESBIC directors, who are usually seniormanagers from sponsoring corporations. The latter(50) often still think mainly in terms of the “social responsi-bility approach” and thus seem to prefer deals that areriskier and
29、less attractive than normal investment criteriawould warrant. Such differences in viewpoint have pro-duced uneasiness among many minority staff members,(55) who feel that minority entrepreneurs and businessesshould be judged by established business considerations.These staff members believe their po
30、int of view is closerto the original philosophy of MESBICs and they areconcerned that, unless a more prudent course is fol-lowed, MESBIC directors may revert to policies likelyto re-create the disappointing results of the original SBAapproach.13. Which of the following best states the central idea o
31、f the passage?(A) The use of MESBICs for aiding minority entrepreneurs seems to have greater potential for success than does the original SBA approach.(B) There is a crucial difference in point of view between the staff and directors of some MESBICs.(C) After initial problems with management and mar
32、keting, minority businesses have begun to expand at a steady rate.(D) Minority entrepreneurs wishing to form new businesses now have several equally successful federal programs on which to rely.(E) For the first time since 1960, large corporations are making significant contributions to the developm
33、ent of minority businesses.14. According to the passage, the MESBIC approach differs from the SBA approach in that MESBICs(A) seek federal contracts to provide marketsfor minority businesses(B) encourage minority businesses to provide markets for other minority businesses(C) attempt to maintain a sp
34、ecified rate of growth in the minority business sector(D) rely on the participation of large corporations to finance minority businesses(E) select minority businesses on the basis of their location15. Which of the following does the author cite to support the conclusion that the results of the SBA p
35、rogram were disappointing?(A) The small number of new minority enterprises formed as a result of the program新东方在线 网络课堂电子教材系列 GMAT 阅读讲义6(B) The small number of minority enterprises that took advantage of the management and technical assistance offiered under the program(C) The small percentage of th
36、e nations business receipts earned by minority enterprises following the programs, implementation.(D) The small percentage of recipient minority enterprises that were able to repay federally guaranteed loans made under the program(E) The small number of minority enterprises that chose to participate
37、 in the program16. Which of the following statements about the SBA program can be inferred from the passage?(A) The maximum term for loans made to recipient businesses was 15 years.(B) Business loans were considered to be more useful to recipient businesses than was management and technical assistan
38、ce.(C) The anticipated failure rate for recipient businesses was significantly lower than the rate that actually resulted.(D) Recipient businesses were encouraged to relocate to areas more favorable for business development.(E) The capitalization needs of recipient businesses were assessed and then
39、provided for adequately.17. The author refers to the “financial and operating problems”(line 38 ) encountered by MESBICs primarily in order to(A) broaden the scope of the discussion to include the legal considerations of funding MESBICS through sponsoring companies(B) call attention to the fact that
40、 MESBICs must receive adequate funding in order to function effectively(C) show that sponsoring companies were willing to invest only $500,000 of government-sponsored venture capital in the original MESBICs(D) compare SBA and MESBIC limits on minimum funding(E) refute suggestions that MESBICs have b
41、een only marginally successful18. The authors primary objective in the passage is to(A) disprove the view that federal efforts to aid minority businesses have been ineffective(B) explain how federal efforts to aid minority businesses have changed since the 1960s(C) establish a direct link between th
42、e federal efforts to aid minority businesses made before the 1960s and those made in the 1980s(D) analyze the basis for the belief that job-specific experience is more useful to minority businesses than is general management experience(E) argue that the “social responsibility approach” to aiding min
43、ority businesses is superior to any other approach新东方在线 网络课堂电子教材系列 GMAT 阅读讲义7Passage 3Seeking a competitive advantage, some professionalservice firms(for example, firms providing advertising,accounting, or health care services) have consideredoffering unconditional guarantees of satisfaction. Such(
44、5) guarantees specify what clients can expect and what thefirm will do if it fails to fulfill these expectations.Particularly with first-time clients, an unconditionalguarantee can be an effective marketing tool if theclient is very cautious, the firms fees are high, the(10) negative consequences of
45、 bad service are grave, orbusiness is difficult to obtain through referrals andword-of-mouth.However, an unconditional guarantee can sometimeshinder marketing efforts. With its implication that fail-(15) ure is possible, the guarantee may, paradoxically, causeclients to doubt the service firms abili
46、ty to deliver thepromised level of service. It may conflict with a firmsdesire to appear sophisticated, or may even suggest thata firm is begging for business. In legal and health care(20) services, it may mislead clients by suggesting that law-suits or medical procedures will have guaranteed out-co
47、mes. Indeed, professional service firms with outstandinreputations and performance to match have little to gainfrom offering unconditional guarantees. And any firm(25) that implements an unconditional guarantee withoutundertaking a commensurate commitment to quality ofservice is merely employing a p
48、otentially costlymarketing gimmick.113. The primary function of the passage as a whole is to(A) account for the popularity of a practice(B) evaluate the utility of a practice(C) demonstrate how to institute a practice(D) weigh the ethics of using a strategy(E) explain the reasons for pursuing a strategy114. All of the following are mentioned in the passage as circumstances in which professional service firms can benefit from offering an unconditional guarantee EXCEPT:(A) The firm is having difficulty retaining its clients of long standing.(B) The firm is having
