问答

1答疑

[Critical Reasoning]

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题目：

Parland’s alligator population has been declining in recent years, primarily because of hunting. Alligators prey heavily on a species of freshwater fish that is highly valued as food by Parlanders, who had hoped that the decline in the alligator population would lead to an increase in the numbers of these fish available for human consumption. Yet the population of this fish species has also declined, even though the annual number caught for human consumption has not increased.

Which of the following, if true, most helps to explain the decline in the population of the fish species?

选项:

A、The decline in the alligator population has meant that fishers can work in some parts of lakes and rivers that were formerly too dangerous.
B、Over the last few years, Parland’s commercial fishing enterprises have increased the number of fishing boats they use.
C、The main predator of these fish is another species of fish on which alligators also prey.
D、Many Parlanders who hunt alligators do so because of the high market price of alligator skins, not because of the threat alligators pose to the fish population.
E、In several neighboring countries through which Parland’s rivers also flow, alligators are at risk of extinction as a result of extensive hunting.

答案:

C
1答疑

[Critical Reasoning]

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题目：

Archaeologist: Researchers excavating a burial site in Cyprus found a feline skeleton lying near a human skeleton. Both skeletons were in the same sediment at the same depth and equally well-preserved, suggesting that the feline and human were buried together about 9,500 years ago. This shows that felines were domesticated around the time farming began, when they would have been useful in protecting stores of grain from mice.

Which of the following, if true, would most seriously weaken the archaeologist’s argument?

选项:

A、Archaeologists have not found any remains of stores of grain in the immediate vicinity of the burial site.
B、The burial site in Cyprus is substantially older than any other known burial site in which a feline skeleton and a human skeleton appear to have been buried together.
C、Paintings found near the burial site seem to show people keeping felines as domestic companions, but do not show felines hunting mice.
D、In Cyprus, there are many burial sites dating from around 9,500 years ago in which the remains of wild animals appear to have been buried alongside human remains.
E、Before felines were domesticated, early farmers had no effective way to protect stores of grain from mice.

答案:

D
1答疑

[Reading Comprehension]

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文章：

In terrestrial environments, gravity places special demands on the cardiovascular systems of animals. Gravitational pressure can cause blood to pool in the lower regions of the body, making it difficult to circulate blood to critical organs such as the brain. Terrestrial snakes, in particular, exhibit adaptations that aid in circulating blood against the force of gravity.

The problem confronting terrestrial snakes is best illustrated by what happens to sea snakes when removed from their supportive medium. Because the vertical pressure gradients within the blood vessels are counteracted by similar pressure gradients in the surrounding water, the distribution of blood throughout the body of sea snakes remains about the same regardless of their orientation in space, provided they remain in the ocean. When removed from the water and tilted at various angles with the head up, however, blood pressure at their midpoint drops significantly, and at brain level falls to zero. That many terrestrial snakes in similar spatial orientations do not experience this kind of circulatory failure suggests that certain adaptations enable them to regulate blood pressure more effectively in those orientations.

One such adaptation is the closer proximity of the terrestrial snake’s heart to its head, which helps to ensure circulation to the brain, regardless of the snake’s orientation in space. The heart of sea snakes can be located near the middle of the body, a position that minimizes the work entailed in circulating blood to both extremities. In arboreal snakes, however, which dwell in trees and often assume a vertical posture, the average distance from the heart to the head can be as little as 15 percent of overall body length. Such a location requires that blood circulated to the tail of the snake travel a greater distance back to the heart, a problem solved by another adaptation. When climbing, arboreal snakes often pause momentarily to wiggle their bodies, causing waves of muscle contraction that advance from the lower torso to the head. By compressing the veins and forcing blood forward, these contractions apparently improve the flow of venous blood returning to the heart.

题目：

It can be inferred from the passage that which of the following is true of species of terrestrial snakes that often need to assume a vertical posture?

选项:

A、They are more likely to be susceptible to circulatory failure in vertical postures than are sea snakes.Their hearts are less likely to be located at the midpoint of their bodies than is the case with sea snakes.
B、They cannot counteract the pooling of blood in lower regions of their bodies as effectively as sea snakes can.
C、The blood pressure at their midpoint decreases significantly when they are tilted with their heads up.
D、They are unable to rely on muscle contractions to move venous blood from the lower torso to the head.

答案:

B
1答疑

[Two-part Analysis]

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题目：

Archaeologist: There were several porcelain-production centers in 18th-century Britain, among them Bristol, Plymouth, and New Hall. Each center developed a unique recipe for its porcelain that might include flint glass, soapstone, bone ash, clay, quartz, and so on. We will therefore be able to determine, on the basis of compositional analysis, where the next cup we recover from this archaeological site was made.

Indicate two different statements as follows: one statement identifies an assumption required by the archaeologist's argument and the other identifies a possible fact that, if true, would, provide significant logical support for the required assumption.

选项:

A、Other cups have been recovered from the archaeological site, all of which were made of porcelain.
B、Some of the cups recovered from the archeological site were not made of porcelain.
C、The next cup to be recovered from the site will likely be made of porcelain.
D、Porcelain makers often traveled between centers, experimenting with one another's recipes.
E、There was considerable overlap of materials in the recipes used by the various centers.
F、Most porcelain in 18th-century Britain was made at one of the several centers.

答案:

C A
1答疑

[Data Sufficiency]

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题目：

A department manager distributed a number of pens, pencils, and pads among the staff in the department, with each staff member receiving x pens, y pencils, and z pads. How many staff members were in the department ?
(1)   The numbers of pens, pencils, and pads that each staff member received were in the ratio 2 : 3 : 4, respectively.
(2)   The manager distributed a total of 18 pens, 27 pencils, and 36 pads.

选项:

答案:

E
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[Data Sufficiency]

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题目：

If n is an integer and 2 < n < 6, what is the value of n?
(1)     n is a factor of 15.
(2)     n is a factor of 21.

选项:

答案:

B
1答疑

[Reading Comprehension]

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文章：

Line         While the most abundant and dominant species
  within a particular ecosystem is often crucial in
  perpetuating the ecosystem, a “keystone” species,
  here defined as one whose effects are much larger
(5) than would be predicted from its abundance, can
  also play a vital role. But because complex species
  interactions may be involved, identifying a keystone
  species by removing the species and observing
  changes in the ecosystem is problematic. It might
(10) seem that certain traits would clearly define a species
  as a keystone species; for example,
  Pisaster ochraceus is often a keystone predator
  because it consumes and suppresses mussel
  populations, which in the absence of this starfish
(15) can be a dominant species. But such predation on a
  dominant or potentially dominant species occurs in
  systems that do as well as in systems that do not
  have species that play keystone roles. Moreover,
  whereas P. ochraceus occupies an unambiguous
(20) keystone role on wave-exposed rocky headlands,
  in more wave-sheltered habitats the impact of
  P. ochraceus predation is weak or nonexistent,
  and at certain sites sand burial is responsible for
  eliminating mussels. Keystone status appears to
(25) depend on context, whether of particular
  geography or of such factors as community
  diversity (for example, a reduction in species
  diversity may thrust more of the remaining species
  into keystone roles) and length of species
(30) interaction (since newly arrived species in particular
  may dramatically affect ecosystems).


题目：

Which of the following hypothetical experiments most clearly exemplifies the method of identifying species’ roles that the author considers problematic?

选项:

A、A population of seals in an Arctic habitat is counted in order to determine whether it is the dominant species in that ecosystem.
B、A species of fish that is a keystone species in one marine ecosystem is introduced into another marine ecosystem to see whether the species will come to occupy a keystone role.
C、In order to determine whether a species of monkey is a keystone species within a particular ecosystem, the monkeys are removed from that ecosystem and the ecosystem is then studied.
D、Different mountain ecosystems are compared to determine how geography affects a particular species’ ability to dominate its ecosystem.
E、In a grassland experiencing a changing climate, patterns of species extinction are traced in order to evaluate the effect of climate changes on keystone species in that grassland.

答案:

C
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[Critical Reasoning]

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题目：

Only a reduction of 10 percent in the number of scheduled flights using Greentown's airport will allow the delays that are so common there to be avoided. Hevelia airstrip, 40 miles away, would, if upgraded and expanded, be an attractive alternative for fully 20 percent of the passengers using Greentown airport. Nevertheless, experts reject the claim that turning Hevelia into a full-service airport would end the chronic delays at Greentown.

Which of the following, if true, most helps to justify the experts' position?

选项:

A、Turning Hevelia into a full-service airport would require not only substantial construction at the airport itself, but also the construction of new access highways.
B、A second largely undeveloped airstrip close to Greentown airport would be a more attractive alternative than Hevelia for many passengers who now use Greentown.
C、Hevelia airstrip lies in a relatively undeveloped area but would, if it became a full-service airport, be a magnet for commercial and residential development.
D、If an airplane has to wait to land, the extra jet fuel required adds significantly to the airline's costs.
E、Several airlines use Greentown as a regional hub, so that most flights landing at Greentown have many passengers who then take different flights to reach their final destinations.

答案:

E
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[Problem Solving]

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题目：

If n is a positive integer and the product of all the integers from 1 to n, inclusive, is divisible by 990, what is the least possible value of n ?

选项:

A、8
B、9
C、10
D、11
E、12

答案:

D
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[Sentence Correction]

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题目：

While some academicians believe that business ethics should be integrated into every business course, others say that students will take ethics seriously only if it would be taught as a separately required course.

选项:

答案:

B
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1293浏览

[Undefined]

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Art historian: Unlike many artistic traditions that sought to depict plants native to the local area in a seasonally appropriate way (for example, depicting scenes of spring with the plants in the appropriate stages of development for that season), seventeenth-century Dutch artists specializing in flower paintings almost exclusively chose to depict exotic species of flowers from outside the local area. Painting such species was worthwhile primarily because the art-buying public had developed a strong preference for images of the exotic. The great botanical centers of the time gave the artists direct access to such flowers, which the artists would freely combine in a single painting, regardless of whether the combined species occurred together in the wild, and depicted each in full bloom, regardless of whether those species bloomed at the same time in nature.

Statement: The art historian makes the point that the species of flowers these Dutch artists chose to paint were 1 largely because the species were 2 .

Select for 1 and for 2 the options that complete the statement so that it is most strongly supported by the information provided. Make only two selections, one in each column.
我选的CE，和EC有什么区别？怎么选出EC的？
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3662浏览

[Undefined]

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An unusually severe winter occurred in Europe after the continent was blanketed by a blue haze resulting from the eruption of the Laki Volcano in the European republic of Iceland in the summer of 1984.  Thus, it is evident that major eruptions cause the atmosphere to become cooler than it would be otherwise.
Which of the following statements, if true, most seriously weakens the argument above?
C选项为什么就不会有张冠李戴的问题呢，1984和1982的气候情况能一样吗，C里的火山就可以试用于原文的火山吗
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4030浏览

[Undefined]

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The rate of a certain chemical reaction is directly proportional to the square of the concentration of chemical A present and inversely proportional to the concentration of chemical B present. If the concentration of chemical B is increased by 100 percent, which of the following is closest to the percent change in the concentration of chemical A required to keep the reaction rate unchanged?
为什么这个题一定是相乘不能是相加呢？y=k1A方-k2B （k1,k2大于0 ），也满足题目说的与A方成正比与B成反比啊？但是这道题只有相乘的情况才能选出正确答案
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1339浏览

[Undefined]

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Tiger beetles are such fast runners that they can capture virtually any nonflying insect.  However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack.  Perhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.
 
Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?
答案C是怎么支持一个猜想又削弱另一个猜想的？
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3005浏览

[GWD]

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The author of the passage implies that which of the following is a possible partial explanation for acquisition behavior during the 1970's and 1980's?
请解释这道题为什么不选C或E，除了正确选项B，我认为文中也正确地提到了这两个选项可以解释acquisition behavior during 1970s and 80s
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2081浏览

[OG]

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The primary purpose of the passage is to
为什么选E不选B
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1336浏览

[Undefined]

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Club X has more than 10 but fewer than 40 members. Sometimes the members sit at tables with 3 members at one table and 4 members at each of the other tables, and sometimes they sit at tables with 3 members at one table and 5 members at each of the other tables. If they sit at tables with 6 members at each table except one and fewer than 6 members at that one table, how many members will be at the table that has fewer than 6 members?
提问小梅老师 这道题求讲一下 我没什么思路 带入数字得的是3
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1407浏览

[Undefined]

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A photography dealer ordered 60 Model X cameras to be sold for $250 each, which represents a 20 percent markup over the dealer's initial cost for each camera. Of the cameras ordered, 6 were never sold and were returned to the manufacturer for a refund of 50 percent of the dealer's initial cost. What was the dealer's approximate profit or loss as a percent of the dealer's initial cost for the 60 cameras?
请问小梅老师 这道题讲讲一下 我算的是19% 原来成本是200每个 亏了6个 每个亏100. 最后得不出答案
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332641浏览

[Undefined]

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Analytical!
请问may老师，这题该用什么思路来做？
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339768浏览

[Undefined]

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Analytical!
请问张老师，这道题为什么D不对？我有我觉得second paragraph最后一句话特别指向D
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