问答

10答疑

[Critical Reasoning]

登录查看答疑

试题详情

题目：

Although fullerenes--spherical molecules made entirely of carbon--were first found in the laboratory, they have since been found in nature, formed in fissures of the rare mineral shungite.  Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, this discovery should give geologists a test case for evaluating hypotheses about the state of the Earth's crust at the time these naturally occurring fullerenes were formed.
 
Which of the following, if true, most seriously undermines the argument?

选项:

A、Confirming that the shungite genuinely contained fullerenes took careful experimentation.
B、Some fullerenes have also been found on the remains of a small meteorite that collided with a spacecraft.
C、The mineral shungite itself contains large amounts of carbon, from which the fullerenes apparently formed.
D、The naturally occurring fullerenes are arranged in a previously unknown crystalline structure.
E、Shungite itself is formed only under distinctive conditions.

答案:

D
10答疑

[Sentence Correction]

登录查看答疑

试题详情

题目：

Almost like clones in their similarity to one another, the cheetah species’ homogeneity makes them especially vulnerable to disease.

选项:

A、the cheetah species’ homogeneity makes them especially vulnerable to disease
B、the cheetah species is especially vulnerable to disease because of its homogeneity
C、the homogeneity of the cheetah species makes it especially vulnerable to disease
D、homogeneity makes members of the cheetah species especially vulnerable to disease
E、members of the cheetah species are especially vulnerable to disease because of their homogeneity

答案:

E
10答疑

[Reading Comprehension]

登录查看答疑

试题详情

文章：

    Earth's surface consists of rigid plates that are constantly shifting and jostling one another. Plate movements are the surface expressions of motions in the mantle—the thick shell of rock that lies between Earth's crust and its metallic core. Although the hot rock of the mantle is a solid, under the tremendous pressure of the crust and overlying rock of the mantle, it flows like a viscous liquid. The mantle's motions, analogous to those in a pot of boiling water, cool the mantle by carrying hot material to the surface and returning cooler material to the depths. When the edge of one plate bends under another and its cooler material is consumed in the mantle, volcanic activity occurs as molten lava rises from the downgoing plate and erupts through the overlying one.

    Most volcanoes occur at plate boundaries. However, certain "misplaced" volcanoes far from plate edges result from a second, independent mechanism that cools the deep interior of Earth. Because of its proximity to Earth's core, the rock at the base of the mantle is much hotter than rock in the upper mantle. The hotter the mantle rock is, the less it resists flowing. Reservoirs of this hot rock collect in the base of the mantle. When a reservoir is sufficiently large, a sphere of this hot rock forces its way up through the upper mantle to Earth's surface, creating a broad bulge in the topography. The "mantle plume" thus formed, once established, continues to channel hot material from the mantle base until the reservoir is emptied. The surface mark of an established plume is a hot spot—an isolated region of volcanoes and uplifted terrain located far from the edge of a surface plate. Because the source of a hot spot remains fixed while a surface plate moves over it, over a long period of time an active plume creates a chain of volcanoes or volcanic islands, a track marking the position of the plume relative to the moving plate. The natural history of the Hawaiian island chain clearly shows the movement of the Pacific plate over a fixed plume.

题目：

It can be inferred from the passage that a chain of volcanoes created by a mantle plume would most likely be characterized by
             
 

选项:

A、a curved outline
B、constituent volcanoes that differ from each other in age
C、occurrence near a plate boundary where one plate bends under another
D、appearance near many other volcanic chains
E、rocks with a wide range of chemical composition

答案:

B
9答疑

[Sentence Correction]

登录查看答疑

试题详情

题目：

Books in European libraries last longer than books in libraries in the United States because, although the climate in Europe is fairly humid, libraries there are not subjected to the extremes of temperature and humidity that damage collections in the United States.

选项:

A、because, although the climate in Europe is fairly humid, libraries there are not subjected to the extremes of temperature and humidity that
B、because, although the climate in Europe is fairly humid, libraries there are not subject of the extremes of temperature and humidity as those that
C、because, although the climate in Europe is fairly humid, libraries there are not subjected to the extremities of temperature and humidity as
D、because the climate in Europe is fairly humid, but still libraries there are not subject of the extremes of temperature and humidity as
E、because the climate in Europe is fairly humid, but libraries there are not subjected to the extremities of temperature and humidity such as those that

答案:

A
9答疑

[Sentence Correction]

登录查看答疑

试题详情

题目：

Dressed as a man and using the name Robert Shurtleff, Deborah Sampson, the first woman to draw a soldier's pension, joined the Continental Army in 1782 at the age of 22, was injured three times, and was discharged in 1783 because she had become too ill to serve.

选项:

A、22, was injured three times, and was discharged in 1783 because she had become
B、22, was injured three times, while being discharged in 1783 because she had become
C、22 and was injured three times, and discharged in 1783, being
D、22, injured three times, and was discharged in 1783 because she was
E、22, having been injured three times and discharged in 1783, being

答案:

A
9答疑

[Sentence Correction]

登录查看答疑

试题详情

题目：

A study by the Ocean Wildlife Campaign urged states to undertake a number of remedies to reverse a decline in the shark population, which includes the establishment of size limits for shark catches, closing state waters for shark fishing during pupping season, and requiring commercial fishers to have federal shark permits.

选项:

A、which includes the establishment of size limits for shark catches, closing
B、which includes establishing limits to the size of sharks that can be caught, closing
C、which include the establishment of size limits for shark catches, the closing of
D、including establishing size limits for shark catches, closing
E、including the establishing of limits to the size of sharks that are caught, the closing of

答案:

D
9答疑

[Critical Reasoning]

登录查看答疑

试题详情

题目：

In parts of the Caribbean, the manatee, an endangered marine mammal, has long been hunted for its meat.  Having noted the manatee hunters' expert knowledge of manatees' habits, local conservationists are encouraging the hunters to stop hunting and instead to take tourists on boat rides to see manatees.  Tourist interest is high, so the plan has promise of achieving the twin goals of giving the former hunters a good income and helping ensure the manatees' survival.
 
Which of the following, if true, raises the most serious doubt about the plan's chance of success?

选项:

A、Many tourists who visit these parts of the Caribbean are uninterested in manatees and would not be willing to pay what the former manatee hunters would have to charge for boat rides to see manatees.
B、Recovery of the species would enable some hunting to continue without putting the manatees' survival in jeopardy again.
C、In areas where manatees have traditionally been hunted for food, local people could easily replace the manatee meat in their diets with other foods obtained from the sea.
D、There would not be enough former manatee hunters to act as guides for all the tourists who want to see manatees.
E、To maintain their current income, manatee hunters who switched to guiding tourists would have to use far larger boats and make many more trips into the manatees' fragile habitat than they currently do.

答案:

E
9答疑

[Critical Reasoning]

登录查看答疑

试题详情

题目：

Which of the following most logically completes the argument below?
 
Although the number of large artificial satellites orbiting the Earth is small compared to the number of small pieces of debris in orbit, the large satellites interfere more seriously with telescope observations because of the strong reflections they produce.  Because many of those large satellites have ceased to function, the proposal has recently been made to eliminate interference from nonfunctioning satellites by exploding them in space.  This proposal, however, is ill conceived, since _______.

选项:

A、many nonfunctioning satellites remain in orbit for years
B、for satellites that have ceased to function, repairing them while they are in orbit would be prohibitively expensive
C、there are no known previous instances of satellites' having been exploded on purpose
D、the only way to make telescope observations without any interference from debris in orbit is to use telescopes launched into extremely high orbits around the Earth
E、a greatly increased number of small particles in Earth's orbit would result in a blanket of reflections that would make certain valuable telescope observations impossible

答案:

E
9答疑

[Critical Reasoning]

登录查看答疑

试题详情

题目：

Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, a tiger beetle will intermittently stop and then, a moment later, resume its attack. Perhaps the beetles 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 adequately 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?

选项:

A、When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately stops and runs away without its usual intermittent stopping.
B、In pursuing a swerving insect, a beetle alters its course while running and its pauses become more frequent as the chase progresses.
C、In pursuing a moving insect, a beetle usually responds immediately to changes in the insect’s direction, and it pauses equally frequently whether the chase is up or down an incline.
D、If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.
E、The faster a beetle pursues an insect fleeing directly away from it, the more frequently the beetle stops.

答案:

B
9答疑

[Sentence Correction]

登录查看答疑

试题详情

题目：

In the sixteenth century, the push for greater precision in measuring time was not, like more recently, motivated by complicated philosophical questions about the nature of matter and the universe, but the practical matters of navigation:  sailors simply needed more highly accurate timepieces in order to compute their longitude from the positions of the stars.

选项:

A、not, like more recently, motivated by complicated philosophical questions about the nature of matter and the universe, but the practical matters of navigation
B、being motivated by the practical matters of navigation, instead of complicated philosophical questions about the nature of matter and the universe, as it has been recently
C、motivated not by complicated philosophical questions about the nature of matter and the universe, like they were more recently, but by the practical matters of navigation
D、motivated by the practical matters of navigation, not complicated philosophical questions about the nature of matter and the universe, which was the case more recently
E、 motivated not by complicated philosophical questions about the nature of matter and the universe, as has been the case more recently, but by the practical matters of navigation

答案:

E
0评分
1122浏览

[Undefined]

登录查看答疑
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？
0评分
3176浏览

[Undefined]

登录查看答疑
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
0评分
3503浏览

[Undefined]

登录查看答疑
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
0评分
1177浏览

[Undefined]

登录查看答疑
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？
0评分
2690浏览

[GWD]

登录查看答疑
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
0评分
1842浏览

[OG]

登录查看答疑
The primary purpose of the passage is to
为什么选E不选B
0评分
1193浏览

[Undefined]

登录查看答疑
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
0评分
1247浏览

[Undefined]

登录查看答疑
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
294793浏览

[Undefined]

登录查看答疑
Analytical!
请问may老师，这题该用什么思路来做？
0评分
301922浏览

[Undefined]

登录查看答疑
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
点我领取
免费专项课程
 在线咨询