问答

1答疑

[Reading Comprehension]

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文章：

    Recently biologists have been interested in a tide-associated periodic behavior displayed by the diatom Hantzschia virgata, a microscopic golden-brown alga that inhabits that portion of a shoreline washed by tides (the intertidal zone).Diatoms of this species, sometimes called "commuter" diatoms, remain burrowed in the sand during high tide, and emerge on the sand surface during the daytime low tide. Just before the sand is inundated by the rising tide, the diatoms burrow again. Some scientists hypothesize that commuter diatoms know that it is low tide because they sense an environmental change, such as an alteration in temperature or a change in pressure caused by tidal movement. However, when diatoms are observed under constant conditions in a laboratory, they still display periodic behavior, continuing to burrow on schedule for several weeks. This indicates that commuter diatoms, rather than relying on environmental cues to keep time, possess an internal pacemaker or biological clock that enables them to anticipate periodic changes in the environment. A commuter diatom has an unusually accurate biological clock, a consequence of the unrelenting environmental pressures to which it is subjected; any diatoms that do not burrow before the tide arrives are washed away.

    This is not to suggest that the period of this biological clock is immutably fixed. Biologists have concluded that even though a diatom does not rely on the environment to keep time, environmental factors—including changes in the tide's hydrostatic pressure, salinity, mechanical agitation, and temperature—can alter the period of its biological clock according to changes in the tidal cycle. In short, the relation between an organism's biological clock and its environment is similar to that between a wristwatch and its owner: the owner cannot make the watch run faster or slower, but can reset the hands. However, this relation is complicated in intertidal dwellers such as commuter diatoms by the fact that these organisms areexposed to the solar-day cycle as well as to the tidal cycle, and sometimes display both solar-day and tidal periods in a single behavior. Commuter diatoms, for example, emerge only during those low tides that occur during the day.

题目：

The author of the passage compares the relationship between an organism's biological clock and its environment to the relation between a wristwatch and its owner most probably in order to

选项:

A、point out a fundamental difference between the function of biological clocks in organisms and the use of mechanical clocks by humans
B、illustrate the way in which the period of an organism's biological clock can be altered by environmental factors
C、suggest that there are important similarities between the biological clock in organisms such as the commuter diatom and the biological clock in humans
D、support an argument regarding the methods used by certain organisms to counteract the influence of the environment on their biological clocks
E、question the accuracy of the biological clock in organisms such as the commuter diatom

答案:

B
1答疑

[Sentence Correction]

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题目：

According to a recent poll, owning and living in a freestanding house on its own land is still a goal of a majority of young adults, like that of earlier generations.

选项:

A、like that of earlier generations
B、as that for earlier generations
C、just as earlier generations did
D、as have earlier generations
E、as it was of earlier generations

答案:

E
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[Problem Solving]

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题目：

On an aerial photograph, the surface of a pond appears as circular region of radius  inch.  If a distance of 1 inch on the photograph corresponds to an actual distance of 2 miles, which of the following is the closest estimate of the actual surface area of the pond, in square miles?

选项:

A、1.3
B、2.4
C、3.0
D、3.8
E、5.0

答案:

B
1答疑

[Data Sufficiency]

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题目：

选项:

A、Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B、Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C、BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D、EACH statement ALONE is sufficient.
E、Statements (1) and (2) TOGETHER are NOT sufficient.

答案:

A
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[Problem Solving]

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题目：

On a certain day, orangeade was made by mixing a certain amount of orange juice with an equal amount of water. On the next day, orangeade was made by mixing the same amount of orange juice with twice the amount of water. On both days, all the orangeade that was made was sold. If the revenue from selling the orangeade was the same for both days and if the orangeade was sold at $0.60 per glass on the first day, what was the price per glass on the second day?

选项:

A、$0.15
B、$0.20
C、$0.30
D、$0.40
E、$0.45

答案:

D
1答疑

[Reading Comprehension]

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文章：

Line         There are recent reports of apparently drastic
  declines in amphibian populations and of extinctions
  of a number of the world’s endangered amphibian
  species. These declines, if real, may be signs of a
(5) general trend toward extinction, and many
  environmentalists have claimed that immediate
  environmental action is necessary to remedy
  this “amphibian crisis,” which, in their view, is an
  indicator of general and catastrophic environmental
(10) degradation due to human activity.
       To evaluate these claims, it is useful to make a
  preliminary distinction that is far too often ignored.
  A declining population should not be confused with
  an endangered one. An endangered population is
(15) always rare, almost always small, and, by definition,
  under constant threat of extinction even without a
  proximate cause in human activities. Its disappearance,
  however unfortunate, should come as no great
  surprise. Moreover, chance events—which may
(20) indicate nothing about the direction of trends in
  population size—may lead to its extinction. The
  probability of extinction due to such random factors
  depends on the population size and is independent of
  the prevailing direction of change in that size.
(25)      For biologists, population declines are potentially
  more worrisome than extinctions. Persistent
  declines, especially in large populations, indicate a
  changed ecological context. Even here, distinctions
  must again be made among declines that are only
(30) apparent (in the sense that they are part of habitual
  cycles or of normal fluctuations), declines that take
  a population to some lower but still acceptable
  level, and those that threaten extinction (e.g., by
  taking the number of individuals below the minimum
(35) viable population). Anecdotal reports of population
  decreases cannot distinguish among these
  possibilities, and some amphibian populations have
  shown strong fluctuations in the past.
       It is indisputably true that there is simply not
(40) enough long-term scientific data on amphibian
  populations to enable researchers to identify real
  declines in amphibian populations. Many fairly
  common amphibian species declared all but extinct
  after severe declines in the 1950s and 1960s
(45) have subsequently recovered, and so might
  the apparently declining populations that have
  generated the current appearance of an amphibian
  crisis. Unfortunately, long-term data will not soon
  be forthcoming, and postponing environmental
(50) action while we wait for it may doom species and
  whole ecosystems to extinction.


题目：

Which of the following best describes the function of the sentence in lines 35–38 ?

选项:

A、To give an example of a particular kind of study
B、To cast doubt on an assertion made in the previous sentence
C、To raise an objection to a view presented in the first paragraph
D、To provide support for a view presented in the first paragraph
E、To introduce an idea that will be countered in the following paragraph

答案:

C
1答疑

[Critical Reasoning]

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题目：

Advertisement: When your car’s engine is running at its normal operating temperature, any major brand of motor oil will protect it about as well as Tuff does. When the engine is cold, it is a different story: Tuff motor oil flows better at lower temperatures than its major competitors do. So, if you want your car’s engine to have maximum protection, you should use Tuff.

Which of the following, if true, most strengthens the argument in the advertisement?

选项:

A、Tuff motor oil provides above-average protection for engines that happen to overheat.
B、Tuff motor oil is periodically supplied free of charge to automobile manufacturers to use in factory-new cars.
C、Tuff motor oil’s share of the engine oil market peaked three years ago.
D、Tuff motor oil, like any motor oil, is thicker and flows less freely at cold temperatures than at hot temperatures.
E、Tuff motor oil is manufactured at only one refinery and shipped from there to all markets.

答案:

A
1答疑

[Data Sufficiency]

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题目：

Water is pumped into a partially filled tank at a constant rate through an inlet pipe. At the same time, water is pumped out of the tank at a constant rate through an outlet pipe. At what rate, in gallons per minute, is the amount of water in the tank increasing?
(1)The amount of water initially in the tank is 200 gallons.
(2)Water is pumped into the tank at a rate of 10 gallons per minute and out of the tank at a rate of 10 gallons every  minutes.

选项:

A、Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B、Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C、BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D、EACH statement ALONE is sufficient.
E、Statements (1) and (2) TOGETHER are NOT sufficient.

答案:

B
1答疑

[Problem Solving]

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题目：

Which of the following inequalities has a solution set that, when graphed on the number line, is a single line segment of finite length?≥ 16

选项:

A、x4≥1
B、x3≤27
C、x2≥ 16
D、2 ≤|x|≤5
E、2 ≤ 3x + 4 ≤ 6

答案:

E
1答疑

[Critical Reasoning]

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文章：

Several industries have recently switched at least partly from older technologies powered by fossil fuels to new technologies powered by electricity. It is thus evident that less fossil fuel is being used as a result of the operations of these industries than would have been used if these industries had retained their older technologies.

题目：

Which of the following, if true, most strengthens the argument above?

选项:

A、Many of the industries that have switched at least partly to the new technologies have increased their output. Less fossil fuel was used to manufacture the machinery employed in the new technologies than was originally used to manufacture the machinery employed in the older technologies. 
B、More electricity is used by those industries that have switched at least partly to the new technologies than by those industries that have not switched
C、Some of the industries that have switched at least partly to the new technologies still use primarily technologies that are powered by fossil fuels
D、The amount of fossil fuel used to generate the electricity needed to power the new technologies is less than the amount that would have been used to power the older technologies.

答案:

E
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1145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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3262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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3614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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1201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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2753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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1895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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[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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1275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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302758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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309885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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