问答

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[Problem Solving]

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题目：

Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y. At these rates, if the two machines together produce 5/4 w widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?

选项:

A、4
B、6
C、8
D、10
E、12

答案:

E
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[Sentence Correction]

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题目：

Sulfur dioxide, a major contributor to acid rain, is an especially serious pollutant because it diminishes the respiratory system's ability to deal with all other pollutants.

选项:

A、an especially serious pollutant because it diminishes the respiratory system's ability to deal
B、an especially serious pollutant because of diminishing the respiratory system's capability of dealing
C、an especially serious pollutant because it diminishes the capability of  the respiratory system in dealing
D、a specially serious pollutant because it diminishes the capability of  the respiratory system to deal
E、a specially serious pollutant because of diminishing the respiratory system's ability to deal

答案:

A
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题目：

In 1981 children in the United States spent an average of slightly less than two and a half hours a week doing household chores; by 1997 they had spent nearly sixhours a week.

选项:

A、chores; by 1997 they had spent nearly six hours a week
B、chores; by 1997 that figure had grown to nearly six hours a week
C、chores, whereas nearly six hours a week were spent in 1997
D、chores, compared with a figure of nearly six hours a week in 1997
E、chores, that figure growing to nearly six hours a week in 1997

答案:

B
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题目：

Under high pressure and intense heat, graphite, the most stable form of pure carbon, changes into the substance commonly referred to as diamond and remaining this way whether or not the heat and pressure are removed.

选项:

A、remaining this way whether or not
B、remaining like that even as
C、remaining as such whether or not
D、remains in this way although
E、remains thus even when

答案:

E
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题目：

A recent review of pay scales indicates that CEO's now earn an average of 419 times more pay than blue-collar workers, compared to a ratio of 42 times in 1980.

选项:

A、 that CEO's now earn an average of 419 times more pay than blue-collar workers, compared to a ratio of 42 times
B、 that, on average, CEO's now earn 419 times the pay of blue-collar workers, a ratio that compares to 42 times
C、 that, on average, CEO's now earn 419 times the pay of blue-collar workers, as compared to 42 times their pay, the ratio
D、 CEO's who now earn on average 419 times more pay than blue-collar workers, as compared to 42 times their pay, the ratio
E、 CEO's now earning an average of 419 times the pay of blue-collar workers, compared to the ratio of 42 times

答案:

C
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题目：

According to a survey of graduating medical students conducted by the Association of American Medical Colleges, minority graduates are nearly four times more likely than are other graduates in planning to practice in socioeconomically deprived areas.

选项:

A、minority graduates are nearly four times more likely than are other graduates in planning to practice
B、minority graduates are nearly four times more likely than other graduates who plan on practicing
C、minority graduates are nearly four times as likely as other graduates to plan on practicing
D、it is nearly four times more likely that minority graduates rather than other graduates will plan to practice
E、it is nearly four times as likely for minority graduates than other graduates to plan to practice

答案:

C
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题目：

In an attempt to guarantee the security of its innovative water purification method, the company required each employee to sign a confidentiality agreement prohibiting that its water purification methods be disclosed to companies using an analogous purification process.

选项:

A、prohibiting that its water purification methods be disclosed to companies
B、prohibiting them from the disclosing of its water purification methods to any company
C、prohibiting disclosure of its water purification methods to any company
D、that would prohibit them from disclosure of its water purification methods to companies
E、that would prohibit its water purification methods to be disclosed to a company

答案:

C
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题目：

Some anthropologists believe that the genetic homogeneity evident in the world's people is the result of a "population bottleneck"—at some time in the past our ancestors suffered an event, greatly reducing their numbers and thus our genetic variation.

选项:

A、at some time in the past our ancestors suffered an event, greatly reducing their numbers
B、that at some time in the past our ancestors suffered an event that greatly reduced their numbers
C、that some time in the past our ancestors suffered an event so that their numbers were greatly reduced,
D、some time in the past our ancestors suffered an event from which their numbers were greatly reduced
E、some time in the past, that our ancestors suffered an event so as to reduce their numbers greatly,

答案:

B
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[Critical Reasoning]

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题目：

Although the discount stores in Goreville's central shopping district are expected to close within five years as a result of competition from a SpendLess discount department store that just opened, those locations will not stay vacant for long.  In the five years since the opening of Colson's, a nondiscount department store, a new store has opened at the location of every store in the shopping district that closed because it could not compete with Colson's.
 
Which of the following, if true, most seriously weakens the argument?

选项:

A、Many customers of Colson's are expected to do less shopping there than they did before the SpendLess store opened.
B、Increasingly, the stores that have opened in the central shopping district since Colson's opened have been discount stores.
C、At present, the central shopping district has as many stores operating in it as it ever had.
D、Over the course of the next five years, it is expected that Goreville's population will grow at a faster rate than it has for the past several decades.
E、Many stores in the central shopping district sell types of merchandise that are not available at either SpendLess or Colson's.

答案:

B
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[Critical Reasoning]

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题目：

In general, jobs are harder to get in times of economic recession because many businesses cut back operations.  However, any future recessions in Vargonia will probably not reduce the availability of teaching jobs at government-funded schools.  This is because Vargonia has just introduced a legal requirement that education in government-funded schools be available, free of charge, to all Vargonian children regardless of the state of the economy, and that current student-teacher ratios not be exceeded.
 
Which of the following, if true, most strengthens the argument?

选项:

A、The current student-teacher ratio at Vargonia's government-funded schools is higher than it was during the most recent period of economic recession.
B、During recent periods when the Vargonian economy has been strong, almost 25 percent of Vargonian children have attended privately funded schools, many of which charge substantial fees.
C、Nearly 20 percent more teachers are currently employed in Vargonia's government-funded schools than had been employed in those schools in the period before the last economic recession.
D、Teachers in Vargonia's government-funded schools are well paid relative to teachers in most privately funded schools in Vargonia, many of which rely heavily on part-time teachers.
E、During the last economic recession in Vargonia, the government permanently closed a number of the schools that it had funded.

答案:

B
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[OG19]

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Each year for 4 years, a farmer increased the number of trees in a certain orchard by of the number of trees in the orchard the preceding year. If all of the trees thrived and there were 6,250 trees in the orchard at the end of the 4-year period, how many trees were in the orchard at the beginning of the 4-year period?
计算过程没有看懂，麻烦may老师再讲一遍
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[OG]

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A sequence of numbers a1, a2, a3, . . . is defined as follows: a1 = 3, a2 = 5, and every term in the sequence after a2 is the product of all terms in the sequence preceding it, e.g., a3 = (a1)(a2) and a4 = (a1)(a2)(a3). If an = t and n ˃ 2, what is the value of an + 2 in terms of t ?
没有听懂an an+1 an+2怎么出来的
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156浏览

[GWD]

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In the rectangular coordinate system, points (4, 0) and (– 4, 0) both lie on circle C. What is the maximum possible value of the radius of C ?
这里的lie on的意思是两个点可以在圆上（相交）也可以在圆的上部（不相交）吗？
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239浏览

[OG]

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Thabo owns exactly 140 books, and each book is either paperback fiction, paperback nonfiction, or hardcover nonfiction. If he owns 20 more paperback nonfiction books than hardcover nonfiction books, and twice as many paperback fiction books as paperback nonfiction books, how many hardcover nonfiction books does Thabo own?
为什么hardcover fiction是0，没有想通是怎么判断的
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418浏览

[OG19]

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There are 10 books on a shelf, of which 4 are paperbacks and 6 are hardbacks. How many possible selections of 5 books from the shelf contain at least one paperback and at least one hardback?
为什么c（4，1）c（6，1）c（8，3）取出来的是不完整的
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390浏览

[Undefined]

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A company plans to assign identification numbers to its employees. Each number is to consist of four different digits from 0 to 9, inclusive, except that the first digit cannot be 0. How many different identification numbers are possible?
这个为什么不能是c（9，1）c（10，1）c（10，1）c（10，1）
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312浏览

[Undefined]

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If money is invested at r percent interest, compounded annually, the amount of the investment will double in approximately  years. If Pat's parents invested $5,000 in a long-term bond that pays 8 percent interest, compounded annually, what will be the approximate total amount of the investment 18 years later, when Pat is ready for college?
没有理解为什么题目意思是每70/8年翻倍一次，我的理解是这个翻倍是一次性的，在70/8年的时候
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[Undefined]

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Scientists have modified feed corn genetically, increasing its resistance to insect pests. Farmers who tried out the genetically modified corn last season applied less insecticide to their corn fields and still got yields comparable to those they would have gotten with ordinary corn. Ordinary corn seed, however, costs less, and what these farmers saved on insecticide rarely exceeded their extra costs for seed. Therefore, for most feed-corn farmers, switching to genetically modified seed would be unlikely to increase profits.

Which of the following would it be most useful to know in order to evaluate the argument?
没有理解为什么D是对的，需要比较的不是普通种子需要的杀虫剂用量吗？为啥转基因corn的杀虫剂用量可以影响结论？
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[Undefined]

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Between 1980 and 2000 the sea otter population of the Aleutian Islands declined precipitously. There were no signs of disease or malnutrition, so there was probably an increase in the number of otters being eaten by predators. Orcas will eat otters when seals, their normal prey, are unavailable, and the Aleutian Islands seal population declined dramatically in the 1980s. Therefore, orcas were most likely the immediate cause of the otter population decline.

Which of the following, if true, most strengthens the argument?
可以理解为什么C对，但是为什么E的slight decline是影响很小到可以忽略不计呢？就是小规模的食物减少也会引起seal减少，从而使orca吃otter
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339浏览

[Undefined]

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When there is less rainfall than normal, the water level of Australian rivers falls and the rivers flow more slowly. Because algae whose habitat is river water grow best in slow-moving water, the amount of algae per unit of water generally increases when there has been little rain. By contrast, however, following a period of extreme drought, algae levels are low even in very slow-moving river water.

Which of the following, if true, does most to explain the contrast described above?
为什么D选项河流短暂干了推出海藻死了，不算过度推理？可能干了很短时间但海藻没死呢？
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