问答

1答疑

[Reading Comprehension]

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试题详情

文章：

All the cells in a particular plant start out with the same complement of genes. How then can these cells differentiate and form structures as different as roots, stems, leaves, and fruits? The answer is that only a small subset of the genes in a particular kind of cell are expressed, or turned on, at a given time. This is accomplished by a complex system of chemical messengers that in plants include hormones and other regulatory molecules. Five major hormones have been identified: auxin, abscisic acid, cytokinin, ethylene, and gibberellin. Studies of plants have now identified a new class of regulatory molecules called oligosaccharins.

Unlike the oligosaccharins, the five well-known plant hormones are pleiotropic rather than specific; that is, each has more than one effect on the growth and development of plants. The five have so many simultaneous effects that they are not very useful in artificially controlling the growth of crops. Auxin, for instance, stimulates the rate of cell elongation, causes shoots to grow up and roots to grow down, and inhibits the growth of lateral shoots. Auxin also causes the plant to develop a vascular system, to form lateral roots, and to produce ethylene.

The pleiotropy of the five well-studied plant hormones is somewhat analogous to that of certain hormones in animals. For example, hormones from the hypothalamus in the brain stimulate the anterior lobe of the pituitary gland to synthesize and release many different hormones, one of which stimulates the release of hormones from the adrenal cortex. These hormones have specific effects on target organs all over the body. One hormone stimulates the thyroid gland, for example, another the ovarian follicle cells, and so forth. In other words, there is a hierarchy of hormones.

Such a hierarchy may also exist in plants. Oligosaccharins are fragments of the cell wall released by enzymes: different enzymes release different oligosaccharins. There are indications that pleiotropic plant hormones may actually function by activating the enzymes that release these other, more specific chemical messengers from the cell wall.

题目：

The author mentions specific effects that auxin has on plant development in order to illustrate the

选项:

A、point that some of the effects of plant hormones can be harmfulway in which hormones are produced by plants
B、hierarchical nature of the functioning of plant hormones
C、differences among the best-known plant hormones
D、concept of pleiotropy as it is exhibited by plant hormones

答案:

E
1答疑

[Data Sufficiency]

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题目：

At a certain university recreation center, a member can receive a 30-minute massage, a 60-minute massage, or a 90-minute massage, and is charged $0.50 per minute for each massage. A member receiving a massage is charged the same fixed amount for each additional service, such as nutrition advice or a fitness evaluation. At this center, what is the total charge to a member for a 60-minute massage and 3 additional services?
  1. At this recreation center, Jordan, a member, had a massage and 3 additional services for a total charge of $37.50.
  2. At this recreation center, Ryan, a member, had a massage and 2 additional services for a total charge of $60.00.

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
1答疑

[Sentence Correction]

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题目：

To read of Abigail Adams’ lengthy separation from her family, her difficult travels, and her constant battles with illness is to feel intensely how harsh life was even for the so-called aristocracy of Revolutionary times.

选项:

A、To read of
B、Reading about
C、Having read about
D、Once one reads of
E、To have read of

答案:

A
1答疑

[Reading Comprehension]

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文章：

题目：

The passage is primarily concerned with

选项:

A、presenting various groups' views of the motives of those proposing certain legislation
B、contrasting the reasoning of various groups concerning their positions on certain proposed legislation
C、tracing the process whereby certain proposed legislation was eventually enacted
D、assessing the success of tactics adopted by various groups with respect to certain proposed legislation
E、evaluating the arguments of various groups concerning certain proposed legislation

答案:

B
1答疑

[Problem Solving]

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题目：

The points R , T , and U  lie on a circle that has radius 4. If the length of arc RTU  is , what is the length of line segment RU  ?

选项:

A、
B、
C、3
D、4
E、6

答案:

D
1答疑

[Sentence Correction]

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题目：

It stood twelve feet tall, weighed nine thousand pounds, and wielded seven-inch claws, and, Megatherium americanum a giant ground sloth, may have been the largest hunting mammal ever to walk the Earth.

选项:

A、
A. It stood twelve feet tall, weighed nine thousand pounds, and wielded seven-inch claws, and Megatherium americanum, a giant ground sloth,
B、
B. It stood twelve feet tall, weighing nine thousand pounds, and wielding seven-inch claws, Megatherium americanum was a giant ground sloth and
C、
C. The giant ground sloth Megatherium americanum, having stood twelve feet tall, weighing nine thousand pounds, and wielding seven-inch claws, it
D、
D. Standing twelve feet tall, weighing nine thousand pounds, and wielding seven-inch claws, Megatherium americanum, a giant ground sloth,
E、
E. Standing twelve feet tall, weighing nine thousand pounds, it wielded seven-inch claws, and the giant ground sloth Megatherium americanum

答案:

D
1答疑

[Problem Solving]

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题目：

In an auditorium, 360 chairs are to be set up in a rectangular arrangement with x rows of exactly y chairs each. If the only other restriction is that 10 < x < 25, how many different rectangular arrangements are possible?

选项:

A、Four
B、Five
C、Six
D、Eight
E、Nine

答案:

B
1答疑

[Data Sufficiency]

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题目：

If $$x$$ and $$y$$ are positive integers, what is the value of $$x$$?

(1)$${3}^{x}{5}^{y}={1},{125}$$

(2)$$y = 3$$

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 statement 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
1答疑

[Problem Solving]

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题目：

A merchant paid $300 for a shipment of x identical calculators. The merchant used two of the calculators as demonstrators and sold each of the others for $5 more than the average (arithmetic mean) cost of the x calculators. If the total revenue from the sale of the calculators was $120 more than the cost of the shipment, how many calculators were in the shipment?

选项:

A、24
B、25
C、26
D、28
E、30

答案:

E
1答疑

[Problem Solving]

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题目：

The cost C, in dollars, to remove p percent of a certain pollutant from a pond is estimated by using the formula . According to this estimate, how much more would it cost to remove 90 percent of the pollutant from the pond than it would cost to remove 80 percent of the pollutant?

选项:

A、$500,000
B、$100,000
C、$50,000
D、$10,000
E、$5,000

答案:

A
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326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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1267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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1444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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561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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1306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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932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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624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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633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
0评分
149287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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156395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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