If n and m are positive integers and m is a factor of 26, what is the greatest possible number of integers that can be equal to both 3n and 26/m
a triangle and a square has N points in common, 问N不可能是下面哪个值?2，4，5，6，8
数列an=an-1-an-2, a1=-5, a2=4, 求a1到a100的和
数列an=an-1-an-2, a1=-5, a2=4, 求a1到a100的和
Science is arguably a very high-minded pursuit, but that is not to say that all of its practitioners are _____, as numerous articles alleging overly generous pharmaceutical industry payments to medical researchers have tried to show.
Without seeming unworldly, William James appeared wholly removed from the _____ of society, the conventionality of academy.
Convinced of the gravity of her poetry, Voigt must have found the reviews of her most recent collection (i)_____ reading: one amused reviewer thought that it was unrecognizable as poetry but decidedly (ii)_____.
The concept of the Hellenistic period in ancient history has proved useful but also _____, with scholars disagreeing on the dates when the period began and ended.
Evidence has been accumulating since the 1930s that reducing an animals energy intake below its energy expenditure extends the life span and delays the (i)_____ of age-related diseases in rats, dogs, fish, and monkeys. Such results have inspired thousands of people to (ii)_____ in the hope of living longer, healthier lives. They have also led to a search for drugs that (iii)_____ the effects of calorie restriction without the pain of actually going on a diet.
Gelles urges readers of Abigail Adams’ letters to consider their (i)_____: in Adams’ era women were denied a public persona separate from that of their husbands. That said, Gelles then (ii)_____ to promote Adams from a writer of private letters to a public figure, arguing that she was a significant force for change.
The humor in this play derives from its (i)_____. The new production, however, inexplicably goes in the opposite direction; it is so (ii)_____ that the audience does not even seem to realize that the play is supposed to be a comedy.
Some social insects, such as bees and ants, are celebrated for their industriousness and engineering feat, but popular culture has not generally _____ termites for theirs—even though they can build mounds twenty feet high.
In matters of taste, the art patron and collector Peggy Guggenheim was _____, she was for the strangest, the most surprising, the most satisfying, the best, the unique.
A. a neophyte
B. a novice
C. a realist
D. an extremist
E. a pragmatist
F. a zealot
Carmen’s affection for her sister, though not _____, was plainly too great to permit a painless departure.
The economist argued that however much the government might trumpet the value of _____, it had been as bold as any other in its spending programs.
The economist argued that however much the government might trumpet the value of _____, it had been as bold as any other in its spending programs.
Early in the development of ice age theories, physicists identified the processing( slow gyration) and wobbling of Earth’s spin axis as the likely drivers of the ice ages, but geologists (i)______, and even the painstaking work done in the 1920s and 1930s by Mihution Mplankovitch failed to (ii)______ of many of the day’s geological experts.
For many in the room, the idea of coming to the assistance of a rival was more than unpleasant: it was _____.
Most capuchin monkey conflict involves such a (i)______ repertoire of gestural and vocal signals that it is difficult for researchers to tease apart the meanings of the individual signals. This (ii)______ is (iii)______ by the fact that many signals seem to shift in meaning according to the context in which they are produced and the developmental stage of the individuals producing them.
It is hardly _____ for today’s film to try to blur the boundaries between the moral and the immoral. Hollywood has been doing that since at least the 1960s.
The students’ _____ natures were in sharp contrast to the imperturbable dispositions of their teacher.
Early practitioners of the natural sciences developed methods to remove distortions caused by either the research environment or the researcher. Such methods, especially with respect to the researcher, were considered to (i)_____ those (ii)_____ subjectivity whose unbridled expression was thought to (iii)_____ research.
The painter has emphasized the figure’s erect posture by making it contrast so starkly with the _____ exhibited by trees of the windswept orchard in the background.
Although political events in different countries were not (i)_____ in the nineteen century, their interrelationship was (ii)_____ compared with the present, when interdependence has become far greater: (iii)_____ has ceased to be an option.
Environmental models—mathematical representations designed to stimulate natural systems—are regularly used by litigants in legal disputes over environmental issues. Unfortunately, the (i)_____ scientific model is (ii)_____ in environmental tort litigation. Because of the adversarial nature of litigation, models are often used by one side to (iii)_____ empirical evidence presented by the other. And because modeling is a particularly technical field, the task of asserting a given model’s relevance and reliability may exceed the abilities of judge and juries.
Since the field of quantum mechanics is often considered to be (i)_____, it was surprising to find it attracts so much (ii)_____ interest.
The astronomer admits that his interpretation of so-called Population III stars is _____ at present since no one has yet done any real calculations to see if it holds up under closer scrutiny.
In establishing that the dust she had observed constitutes two percent of the mass in the quadrant, the astronomer showed that the dust’s extreme visual prominence _____ its relatively minor contribution to the total mass of the region.
Several studies (i)_____ the assumption that paper cups, because they were made of natural products, were more environmentally (ii)_____ than cups made of plastic (polystyrene). Indeed, these studies indicated that the environmental (iii)_____ of producing and recycling paper cups were similar to, if not more than, those related to the production, disposal, and recycling of polystyrene cups.
For all the _____ the new CEO has received from the press recently, her staff have a decidedly less rosy view of her.
In her works, she (i)_____ confidence. She gets excessively (ii)_____ to authorities, even when rejecting their views.
Scientists have argued not only that the chains of atoms called ladder compounds have _____ theoretical interest but also that studies of such systems can lead to important practical applications.
Although many hypotheses have been proposed to explain why some plant communities are more susceptible than others to invasion by nonnative species, results from field studies have been inconsistent and no general theory of invasibility has yet emerged. However, a theory based on fluctuating resource availability could integrate most existing hypotheses and successfully resolve many of the apparently conflicting and ambiguous results of previous studies. The suggested theory is that a plant community becomes more susceptible to invasion whenever there is an increase in the amount of unused resources.
The diversity in the range of resource-release mechanisms could partly explain the absence of consistent ecological correlates of invasibility. In particular, the theory predicts that there will be no necessary relationship between the species diversity of a plant community and its susceptibility to invasion, since near-complete exploitation can each occur in both species-rich and species-poor communities. Though Lonsdale found a positive association between species richness and invasion, this may arise from the tendency of diverse plant communities to be nutrient poor and therefore more responsive to the effects of human-caused influxes of nutrients.
The passage is primarily concerned with
A. assessing the empirical success of a theory
B. explaining why no consistent theoretical account of a phenomenon has been possible
C. advocating a potential solution to a theoretical impasse
D. deducing testable predictions from a proposed theory
E. describing the difficulties involved in explaining certain empirical results
It can be inferred that the author would most likely agree with which of the following assessments of the results from field studies
A. Many of the results contradicted predictions of susceptibility to invasion that are based on the availability of resources unused by the community.
B. If fluctuating resource availability were taken into account, many of the apparent inconsistencies among the results could be explained.
C. The apparent inconsistencies and ambiguities in the results are caused by trying to make them fit an inadequate general theory of invasibility.
D. No general theory of invasibility has emerged because none of the studies has been able to assess the degree of an invasion accurately.
E. The results tend to show a degree of susceptibility to invasion that is lower than would be expected given the prevalence in the wild of nonnative species.
According to the author, the theory based on fluctuating resource availability might resolve “apparently conflicting and ambiguous results” because
A. It explains how a particular circumstance can produce disparate effects.
B. It does not assume that all of the results are instances of the phenomenon that the theory is intended to explain.
C. It predicts that seemingly minor variations in research methodology can have a dramatic effect on results.
D. Its account is based on a statistical tendency rather than on the supposition that the results arise from a causal connection.
E. It indicates why a similar outcome may be preceded by very different circumstances on different occasions.
Exotic insect pests can produce both short-and long-term effects on forest ecosystems. Short-term effects include the disturbances directly associated with the action of the pest, which may cause the defoliation, loss of vigor, or death of trees. Long-term effects are primarily mediated by changes in tree species composition and the consequent alterations of forest structure, productivity, and nutrient uptake. Exotic pests are more efficient than most abiotic disturbances (e.g., fire or wind) at producing long-term changes in species composition. Pests often target specific tree species and, if they become established, they usually remain as permanent components of the ecosystem. Shifts in forest species composition ramify through the ecosystem in many ways because tree species have different, often unique properties.
Consider each of the choices separately and select all that apply.
The passage mentions which of the following as effects of exotic pests on forest ecosystems?
A. decreased vitality in trees
B. defoliation of trees
C. changes in forest structure
The author of the passage mentions the “unique properties” of tree species primarily in order to help explain
A. why pests tend to target specific tree species
B. why pests can have long-term effects on entire ecosystems
C. how pests contribute to shifts in forest species composition
D. how pests are able to become established in an ecosystem
E. how some tree species are able to withstand the effects of pests
When studying shrimp feeding from hydro-thermal vents at the bottom of the ocean, biologists were surprised that the shrimps’ reproductive cycles followed seasonal patterns. Far beyond the reach of sunlight, and with food abundant around the vents all year round, why should such animals reproduce seasonally? The answer might involve their offspring, which in their larval form drift in the currents to colonize new vents. The larvae must feed during their trip, and their springtime release coincides with a peak in algae raining down from surface waters. So far, researchers have found no evidence of seasonal breeding among vent-dwelling species that provide their offspring with yolk to sustain them or among vent-dwelling species found in areas of the ocean with not seasonal algae blooms.
Which of the following best describes the function of the highlighted sentence?
A. It casts doubt on the accuracy of earlier observations of seasonal breeding among shrimp species living near hydro-thermal vents.
B. It undermines the explanation proposed for seasonal breeding among some shrimp species living near hydro-thermal vents.
C. It suggests that alternative theories are needed to explain seasonal breeding among shrimp species living near hydro-thermal vents.
D. It describes the survival benefits to shrimp of mating in parts of the ocean where algae blooms rain down abundantly.
E. It supports the explanation proffered for the seasonal breeding observed among some shrimp species living near hydro-thermal vents.
Our terrestrial food supply comes from ecosystems transformed to produce a few comestible species through the removal of competitors, predators, and pests, but marine capture fisheries depend on the overall productivity of natural ecosystems. There is, however, increasing concern about the impact of fishing and other human activities on marine ecosystems, which are now far from pristine. One option for moving toward both biodiversity and terrestrial food supply goals is to produce greater yields from less land, thereby freeing land for conservation purposes. By contrast, the objective of maintaining or resorting the biodiversity of marine ecosystems may conflict with the objective of maintaining or increasing our food supply from the sea, since the level of fishing required to achieve the latter may compromise the former.
The primary purpose of the passage is to
A. examine the impact of certain research findings regarding changes to ecosystem biodiversity.
B. discuss a possible implication of a difference between terrestrial and marine food supply sources.
C. describe the consequences of a certain kind of interaction between terrestrial and marine ecosystems.
D. identify an area of ecosystem research in which here are significant uncertainties.
E. present evidence that undermines one side of a debate about biodiversity and supports the other.
According to the passage, increasing the food yield per unit of land can have which of the following effects?
A. enabling more land to be used for development purposes
B. compromising progress toward conservation goals
C. helping protect comestible species from competition and predation
D. helping reduce pressure on marine ecosystems
E. helping restore the biodiversity of terrestrial ecosystems
In 1755 British writer Samuel Johnson published an acerbic letter to Lord Chesterfield rebuking his patron for neglect and declining further support. Johnson’s rejection of his patron’s belated assistance has often been identified as a key moment in the history of publishing, marking the end of the culture of patronage. However, patronage had been in decline for 50 years, yet would survive, in attenuated form, for another 50.Indeed, Johnson was in 1762 awarded a pension by the Crown—a subtle form of sponsorship, tantamount to state patronage. The importance of Johnson’s letter is not so much historical as emotional; it would become a touchstone for all who repudiated patrons and for all who embraced the laws of the marketplace.
The author of the passage mentions Johnson’s 1762 pension award in order to
A. reveal that Johnson remained consistent in his rebuke of Lord Chesterfield well after 1755
B. provide evidence for a general trend in the latter half of the eighteenth century of private patronage’s being replaced by state sponsorship
C. situate the debate over the end of patronage within the wider realm of eighteenth-century economic history
D. suggest that Johnson’s letter to Chesterfield was noticed by the Crown only years after it was published
E. emphasize that patronage still helped support Johnson’s writing after his letter to Chesterfield
Which of the following best describes the function of the highlighted phrase in the context of the passage as a whole? (patronage had been in decline for 50 years, yet would survive, in attenuated form, for another 50)
A. It points out the most obvious implications of Johnson’s letter to his patron.
B. It suggests a motivation for Johnson’s rejection of Chesterfield’ s patronage.
C. It provides information that qualifies the assertion that Johnson’s letter sharply defined of the end of a publishing era.
D. It provides a possible defense for Chesterfield’s alleged neglect of Johnson.
E. It refutes the notion the patrons are found primarily among the nobility.
The revival of mural painting that has occurred in San Francisco since the 1970s, especially among the Chicano population of the city’s Mission District, has marked differences from its social realist forerunner in Mexico and the United States some 40 years earlier. Rather than being government sponsored and limited to murals on government buildings, the contemporary mural movement sprang from the people themselves, with murals appearing on community buildings and throughout college campuses. Perhaps the biggest difference, however, is the process. In earlier twentieth-century Mexico, murals resulted from the vision of individual artists. But today’s murals are characteristically the products of artists working with local residents on design and creation.
Such community engagement is characteristic of the Chicano art movement as a whole, which evolved from the same foundations as the Chicano civil rights movement of the mid-1960s. Both were a direct response to the needs of Chicanos in the United States, who were fighting for the right to adequate education, political empowerment, and decent working conditions. Artists joined other cultural workers in making political statements and played a key role in taking these statements to the public. They developed collectives and established cultural centers that functioned as the public-relations arm of the Chicano sociopolitical movement.
The primary purpose of the passage is to
A. argue for the superiority of a style of art
B. consider the impact of an art movement
C. describe the political content of a certain works of art
D. detail the characteristic style of an art movement
E. place an art movement in its historical context
According to the passage, which of the following statements about the “cultural centers” is true?
A. They were the venue where many later leaders of the Chicano civil rights movement first became politically active.
B. Though later widespread, they originated in San Francisco area.
C. Springing up in a number of communities, they initially had largely apolitical goals centered on art instruction.
D. They constituted the nucleus from which the Chicano civil rights movement originated.
E. Founded by artists, they provided support for the Chicano civil rights movement.
Which of the following best describes the relationship between the first paragraph and the second paragraph of the passage?
A. The first focuses on the mural artists as individuals; the second, on their actions as a group.
B. The first compares the mural revival with an earlier artistic movement; the second describes the context contemporary to the revival
C. The first defines the revival by distinguishing it from an earlier artistic movement; the second addresses the political goals of both the revival and its forerunner
D. The first presents an apparently plausible account of the relationship between the revival and is forerunner, the second calls that account into question
E. The first is concerned with the artistic aims and ambitions behind the San Francisco murals; the second considers their political significance
Analyzing levels of proportional representation of American Indians in state and local government jobs is important for several reasons. First, the basic idea underlying the theory of representative bureaucracy is that the demographic composition of bureaucracy should mirror the demographic composition of the general public. This is because in addition to its symbolic value, increased access to managerial position may lead to greater responsiveness on the part of policy makers to the policy interests of traditionally disadvantaged groups such as American Indians. Second, the focus on higher level jobs in bureaucracies (as opposed to non-managerial positions) is especially important because managerial positions represent a major source of economic progress for members of traditionally disadvantaged groups, as these jobs confer good salaries, benefits, status, security, and mobility. Third, it is important to know if there has been growth in the American Indian share of more desirable public sector positions over the last two decades. For instance, Peterson and Duncan argue that the population and power of American Indians have been growing in certain states. Peterson and Duncan also suggest that this growth may reflect the possibility that American Indian population are becoming more active in nontraditional areas of politics, assimilating into mainstream culture, and securing with greater frequency leadership positions in non-tribal government.
The primary purpose of the passage is to
A. summarize a demographic trend over time
B. present findings on a demographic group
C. analyze the demographic composition of a type of job
D. explain the need for particular social research
E. argue for the implementation of a social policy
Which of the following best describes the function of the highlighted sentence in the context of the passage as whole?
A. It hypothesizes a phenomenon that might explain a point made in the preceding sentence.
B. It provides evidence that undermines that assertion made in the first sentence.
C. It offers a projection regarding the development of a trend mentioned earlier in the passage.
D. It presents an interpretation of a discrepancy noted earlier in the passage.
E. It proposed an implementation of a policy mentioned in the preceding sentence.
The passage suggests which of the following regarding “access to managerial positions” for disadvantaged groups?
A. This access is only significant when the percentage of disadvantaged group members in managerial positions mirrors the percent of that group in the general public.
B. This access is largely the result of policy decisions made response to interest of those groups.
C. This access has meaning apart from any policy benefits it confer on those groups.
D. This access often creates increased access to non-managerial position for those groups.
E. The extent of this access tends to be similar across different disadvantaged groups.
Although, recent years have seen substantial reductions in noxious pollutants from individual motor vehicles, the number of such vehicles has been steadily increasing, consequently, more than 100 cities in the United States still have levels of carbon monoxide, particulate matter, and ozone (generated by photochemical reactions with hydrocarbons from vehicle exhaust) that exceed legally established limits. There is a growing realization that the only effective way to achieve further reductions in vehicle emissions—short of a massive shift away from the private automobile—is to replace conventional diesel fuel and gasoline with cleaner-burning fuels such as compressed natural gas, liquefied petroleum gas, ethanol, or methanol.
All of these alternatives are carbon-based fuels whose molecules are smaller and simpler than those of gasoline. These molecules burn more cleanly than gasoline, in part because they have fewer, if any, carbon-carbon bonds, and the hydrocarbons they do emit are less likely to generate ozone. The combustion of larger molecules, which have multiple carbon-carbon bonds, involves a more complex series of reactions. These reactions increase the probability of incomplete combustion and are more likely to release uncombusted and photochemically active hydrocarbon compounds into the atmosphere. On the other hand, alternative fuels do have drawbacks. Compressed natural gas would require that vehicles have a set of heavy fuel tanks—a serious liability in terms of performance and fuel efficiency—and liquefied petroleum gas faces fundamental limits on supply.
Ethanol and methanol, on the other hand, have important advantages over other carbon-based alternative fuels: they have a higher energy content per volume and would require minimal changes in the existing network for distributing motor fuel. Ethanol is commonly used as a gasoline supplement, but it is currently about twice as expensive as methanol, the low cost of which is one of its attractive features. Methanol’s most attractive feature, however, is that it can reduce by about 90 percent the vehicle emissions that form ozone, the most serious urban air pollutant.
Like any alternative fuel, methanol has its critics. Yet much of the criticism is based on the use of “gasoline clone” vehicles that do not incorporate even the simplest design improvements that are made possible with the use of methanol. It is true, for example, that a given volume of methanol provides only about one-half of the energy that gasoline and diesel fuel do; other things being equal, the fuel tank would have to be somewhat larger and heavier. However, since methanol-fueled vehicles could be designed to be much more efficient than “gasoline clone” vehicles fueled with methanol, they would need comparatively less fuel. Vehicles incorporating only the simplest of the engine improvements that methanol makes feasible would still contribute to an immediate lessening of urban air pollution.
According to the passage, incomplete combustion is more likely to occur with gasoline than with an alternative fuel because
A. the combustion of gasoline releases photochemically active hydrocarbons
B. the combustion of gasoline involves an intricate series of reactions
C. gasoline molecules have a simple molecular structure
D. gasoline is composed of small molecules.
E. gasoline is a carbon-based fuel
Which of the following most closely parallels the situation described in the first sentence of the passage?
A. Although a town reduces its public services in order to avoid a tax increase, the town’s tax rate exceeds that of other towns in the surrounding area.
B. Although a state passes strict laws to limit the type of toxic material that can be disposed of in public landfills, illegal dumping continues to increase.
C. Although a town’s citizens reduce their individual use of water, the town’s water supplies continue to dwindle because of a steady increase in the total population of the town.
D. Although a country attempts to increase the sale of domestic goods by adding a tax to the price of imported goods, the sale of imported goods within the country continues to increase.
E. Although a country reduces the speed limit on its national highways, the number of fatalities caused by automobile accidents continues to increase.
It can be inferred from the passage that a vehicle specifically designed to use methanol for fuel would
A. be somewhat lighter in total body weight than a conventional vehicle fueled with gasoline
B. be more expensive to operate than a conventional vehicle fueled with gasoline
C. have a larger and more powerful engine than a conventional vehicle fueled with gasoline
D. have a larger and heavier fuel tank than a “gasoline clone” vehicle fueled with methanol
E. average more miles per gallon than a “gasoline clone” vehicle fueled with methanol
The passage suggests which of the following about air pollution?
A. Further attempts to reduce emissions from gasoline-fueled vehicles will not help lower urban air-pollution levels.
B. Attempts to reduce the pollutants that an individual gasoline-fueled vehicle emits have been largely unsuccessful.
C. Few serious attempts have been made to reduce the amount of pollutants emitted by gasoline-fueled vehicles.
D. Pollutants emitted by gasoline-fueled vehicles are not the most critical source of urban air pollution.
E. Reductions in pollutants emitted by individual vehicles have been offset by increases in pollution from sources other than gasoline-fueled vehicles.