问答

2答疑

[Problem Solving]

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题目：

According to a certain estimate, the depth N(t), in centimeters, of the water in a certain tank at t hours past 2:00 in the morning is given by N(t) = –20(t – 5)2 + 500 for 0 ≤ t ≤ 10. According to this estimate, at what time in the morning does the depth of the water in the tank reach its maximum?

选项:

A、5:30
B、7:00
C、7:30
D、8:00
E、9:00

答案:

B
2答疑

[Reading Comprehension]

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文章：

    In the 1930's and 1940's, African American industrial workers in the southern United States, who constituted 80 percent of the unskilled factory labor force there, strongly supported unionization. While the American Federation of Labor (AFL) either excluded African Americans or maintained racially segregated unions, the Congress of Industrial Organizations (CIO) organized integrated unions nationwide on the basis of a stated policy of equal rights for all, and African American unionists provided the CIO's backbone. Yet it can be argued that through contracts negotiated and enforced by White union members, unions—CIO unions not excluded—were often instrumental in maintaining the occupational segregation and other forms of racial discrimination that kept African Americans socially and economically oppressed during this period. However, recognizing employers' power over workers as a central factor in African Americans' economic marginalization, African American workers saw the need to join with White workers in seeking change despite White unionists' toleration of or support for racial discrimination. The persistent efforts of African American unionists eventually paid off: many became highly effective organizers, gaining the respect of even racist White unionists by winning victories for White as well as African American workers. African American unionists thus succeeded in strengthening the unions while using them as instruments of African Americans' economic empowerment.

题目：

According to the passage, which of the following was true of many racist White unionists during the period discussed in the passage?

选项:

A、Their attitudes toward African American union organizers changed once they recognized that the activities of these organizers were serving workers' interests.
B、They were a powerful element in the southern labor movement because they constituted the majority of the unskilled factory labor force in the southern United States.
C、They persisted in opposing the CIO's adoption of a stated policy of equal rights for all.
D、Their primary goal was to strengthen the negotiating power of the unions through increasing White union membership.
E、Their advocacy of racial discrimination hampered unions in their efforts to gain more power for workers.

答案:

A
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[Problem Solving]

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题目：

In a meeting of 3 representatives from each of 6 different companies, each person shook hands with every person not from his or her own company. If the representatives did not shake hands with people from their own company, how many handshakes took place?

选项:

A、45
B、135
C、144
D、270
E、288

答案:

B
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[Data Sufficiency]

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题目：

What is the median number of employees assigned per project for the projects at Company Z?
(1)   25 percent of the projects at Company Z have 4 or more employees assigned to each project.
(2) 35 percent of the projects at Company Z have 2 or fewer employees assigned to each project.

选项:

答案:

C
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[Sentence Correction]

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题目：

Japanese researchers are producing a series of robots that can identify human facial expressions, to which they will then respond; their goal is primarily creating a robot that will empathize with us.

选项:

A、 expressions, to which they will then respond; their goal is primarily creating
B、 expressions, then responding to them; primarily to create
C、 expressions and then respond to them; the researchers' primary goal is to create
D、 expressions as well as giving a response to them; their primary goal is creation of
E、 expressions and responding to them; primarily, the researchers' goal is creating

答案:

C
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[Sentence Correction]

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题目：

Elizabeth Barber, the author of both Prehistoric Textiles, a comprehensive work on cloth in the early cultures of the Mediterranean, and also of Women's Work, a more general account of early cloth manufacture, is an expert authority on textiles in ancient societies.

选项:

A、also of Women's Work, a more general account of early cloth manufacture, is an expert authority on
B、also Women's Work, a more general account of cloth manufacture, is an expert authority about
C、of Women's Work, a more general account about early cloth manufacture, is an authority on
D、of Women's Work, a more general account about early cloth manufacture, is an expert authority about
E、Women's Work, a more general account of early cloth manufacture, is an authority on

答案:

E
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[Reading Comprehension]

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文章：

Line         Most attempts by physicists to send particles
  faster than the speed of light involve a remarkable
  phenomenon called quantum tunneling, in which
  particles travel through solid barriers that appear
(5) to be impenetrable. If you throw a ball at a wall,
  you expect it to bounce back, not to pass straight
  through it. Yet subatomic particles perform the
  equivalent feat. Quantum theory says that there is a
  distinct, albeit small, probability that such a particle
(10) will tunnel its way through a barrier; the probability
  declines exponentially as the thickness of the
  barrier increases. Though the extreme rapidity of
  quantum tunneling was noted as early as 1932,
  not until 1955 was it hypothesized—by Wigner and
(15) Eisenbud—that tunneling particles sometimes
  travel faster than light. Their grounds were
  calculations that suggested that the time it takes a
  particle to tunnel through a barrier increases with
  the thickness of the barrier until tunneling time
(20) reaches a maximum; beyond that maximum,
  tunneling time stays the same regardless of
  barrier thickness. This would imply that once
  maximum tunneling time is reached, tunneling
  speed will increase without limit as barrier thickness
(25) increases. Several recent experiments have
  supported this hypothesis that tunneling particles
  sometimes reach superluminal speed. According to
  measurements performed by Raymond Chiao and
  colleagues, for example, photons can pass through
(30) an optical filter at 1.7 times the speed of light.


题目：

The author of the passage mentions calculations about tunneling time and barrier thickness in order to

选项:

A、suggest that tunneling time is unrelated to barrier thickness
B、explain the evidence by which Wigner and Eisenbud discovered the phenomenon of tunneling
C、describe data recently challenged by Raymond Chiao and colleagues
D、question why particles engaged in quantum tunneling rarely achieve extremely high speeds
E、explain the basis for Wigner and Eisenbud’s hypothesis

答案:

E
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[Critical Reasoning]

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文章：

In order to reduce the number of items damaged while in transit to customers, packaging consultants recommended that the TrueSave mail-order company increase the amount of packing material so as to fi ll any empty spaces in its cartons. Accordingly, TrueSave offi cials instructed the company’s packers to use more packing material than before, and the packers zealously acted on these instructions and used as much as they could. Nevertheless, customer reports of damaged items rose somewhat.

题目：

Which of the following, if true, most helps to explain why acting on the consultants’ recommendation failed to achieve its goal?

选项:

A、The change in packing policy led to an increase in expenditure on packing material and labor.When packing material is compressed too densely, it loses some of its capacity to absorb shock.
B、The amount of packing material used in a carton does not signifi cantly infl uence the ease with which a customer can unpack the package
C、Most of the goods that TrueSave ships are electronic products that are highly vulnerable to being damaged in transit.
D、TrueSave has lost some of its regular customers as a result of the high number of damaged items they received. 

答案:

B
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[Sentence Correction]

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题目：

Yellow jackets number among the 900 or so species of the world's social wasps, wasps living in a highly cooperative and organized society where they consist almost entirely of females—the queen and her sterile female workers.

选项:

A、wasps living in a highly cooperative and organized society where they consist almost entirely of
B、wasps that live in a highly cooperative and organized society consisting almost entirely of
C、which means they live in a highly cooperative and organized society, almost all
D、which means that their society is highly cooperative, organized, and it is almost entirely
E、living in a society that is highly cooperative, organized, and it consists of almost all

答案:

B
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[Sentence Correction]

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题目：

Antarctica receives more solar radiation than does any other place on Earth, yet the temperatures are so cold and the ice cap is reflective, so that little polar ice melts during the summer; otherwise, the water levels of the oceans would rise 250 feet and engulf most of the world's great cities.

选项:

A、is reflective, so that little polar ice melts during the summer; otherwise,
B、is so reflective that little of the polar ice melts during the summer; were it to do so,
C、so reflective that little polar ice melts during the summer, or else
D、reflective, so that little of the polar ice melts during the summer, or
E、reflects so that little of the polar ice melts during the summer; if it did

答案:

B
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1288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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[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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4018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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1336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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2994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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[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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[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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[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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338249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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