问答

1答疑

[Reading Comprehension]

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试题详情

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 a true statement about sea snakes?

选项:

A、They frequently rely on waves of muscle contractions from the lower torso to the head to supplement the work of the heart.They cannot effectively regulate their blood pressure when placed in seawater and tilted at an angle with the head pointed downward.
B、They are more likely to have a heart located in close proximity to their heads than are arboreal snakes.
C、They become acutely vulnerable to the effects of gravitational pressure on their circulatory system when they are placed in a terrestrial environment.
D、Their cardiovascular system is not as complicated as that of arboreal snakes.

答案:

D
1答疑

[Data Sufficiency]

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题目：

What is the value of 3-(x + y ) / 3-(x - y )?
(1)     x = 2
(2)     y = 3

选项:

答案:

B
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[Problem Solving]

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题目：

Aaron will jog from home at x miles per hour and then walk back home by the same route at y miles per hour. How many miles from home can Aaron jog so that he spends a total of t  hours jogging and walking?

选项:

A、
B、
C、
D、
E、

答案:

C
1答疑

[Reading Comprehension]

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文章：

Line This passage is excerpted from material published
in 1997.
Is there a massive black hole at the center of our
galaxy, the Milky Way? The evidence is inconclusive.
(5) Just as the Sun’s mass can be determined, given
knowledge of other variables, by the velocity at
which its planets orbit, the mass at the center of the
Milky Way can be revealed by the velocities of stars
and gas orbiting the galactic center. This dynamical
(10) evidence, based on recently confirmed assumptions
about the stars’ velocities, argues for an extremely
compact object with a mass two to three million
times the mass of our Sun. Although according to
current theory this makes the mass at the center
(15) of the galaxy too dense to be anything but a black
hole, the relative lack of energy radiating from the
galactic center presents a serious problem. A black
hole’s gravity attracts surrounding matter, which
swirls around the black hole, emitting some energy
(20) as it is engulfed. Scientists believe that the amount of
energy that escapes the black hole should be about
10 percent of the matter’s rest energy (the energy
equivalent of its mass according to the equation
E=mc2). But when the energy coming from the
(25) galactic center is compared to widely held predictions
based on how much matter should be falling into a
theoretical central black hole, there is a discrepancy
by a factor of a few thousand.

题目：

The “serious problem” referred to in line 17 could be solved if which of the following were true?

选项:

A、Current assumptions about how much matter a black hole would engulf proved to be several thousand times too high.
B、Current assumptions about how much matter a black hole would engulf proved to be a few thousand times too low.
C、The object at the center of the Milky Way turned out to be far more dense than it is currently estimated to be.
D、The object at the center of the Milky Way turned out to be far more massive than it is currently estimated to be.
E、Matter being engulfed by a black hole radiated far more energy than is currently assumed.

答案:

A
1答疑

[Data Sufficiency]

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题目：

A company produces a certain toy in only 2 sizes, small or large, and in only 2 colors, red or green. If, for each size, there are equal numbers of red and green toys in a certain production lot, what fraction of the total number of green toys is large?
  1. In the production lot, 400 of the small toys are green.
  2. In the production lot, of the toys produced are small.

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
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[Data Sufficiency]

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题目：

Is the positive two-digit integer N less than 40 ?
  1. The units digit of N is 6 more than the tens digit.
  2. N is 4 less than 4 times the units digit.

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:

D
1答疑

[Critical Reasoning]

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文章：

In many scientific disciplines, scientists generally do not do highly creative work beyond the age of forty, a tendency that has normally been taken to show that aging carries with it a loss of creative capacity. However, by the age of forty most scientists have been working in their chosen field for at least fifteen years, so an alternative explanation is that spending too long in a single field reduces the opportunity for creative thought.

题目：

Investigating which of the following would be most useful in choosing between the competing explanations described above?

选项:

A、Whether among those scientists who do highly creative work beyond age forty a large proportion entered their field at a considerably later age than is common Whether scientists' choice of research projects tends to be influenced by their own belief that their most creative work will be done relatively early in their career
B、Whether scientists who are older than forty tend to find more satisfaction in other activities, such as teaching and mentoring, than they do in pursuing their own research
C、Whether funding agencies are more inclined to award research grants to scientists who are veterans in their field than to scientists who are relative newcomers 
D、Whether there is significant variation among scientific fields in the average age at which scientists working in those fields are at their most productive

答案:

A
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[Problem Solving]

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题目：

If 3/104 = x percent, then x =?

选项:

A、0.3
B、0.03
C、0.003
D、0.0003
E、0.00003

答案:

B
1答疑

[Data Sufficiency]

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题目：

In the xy-plane, does the line with equation y = 3x + 2 contain the point (r, s) ?
(1) (3r + 2 – s)(4r + 9 – s) = 0
(2) (4r – 6 – s)(3r + 2 – s) = 0

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:

C
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[Problem Solving]

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题目：

At a certain food stand, the price of each apple is ¢ 40 and the price of each orange is ¢ 60. Mary selects a total of 10 apples and oranges from the food stand, and the average (arithmetic mean) price of the 10 pieces of fruit is ¢ 56.  How many oranges must Mary put back so that the average price of the pieces of fruit that she keeps is ¢ 52?

选项:

A、1
B、2
C、3
D、4
E、5

答案:

E
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340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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1292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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1470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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568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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1320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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942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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631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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639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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151156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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158264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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