三种方式weaken：
1。举反例证明结论错，如：缺少必要assumption/缺少不变量：如平均值、总量、百分比、比率等；
2。找出更合理他因；
3。削弱“证据”与结论间的因果关联性
4。取非支持为最削弱项
GWD-1-Q13:选了C
In the United States, of the people who moved from one state to another when they retired, the percentage who retired to Florida has decreased by three percentage points over the past ten years. Since many local businesses in Florida cater to retirees, this decline is likely to have a noticeably negative economic effect on these businesses.
Which of the following, if true, most seriously weakens the argument?
A. Florida attracts more people who move from one state to another when they retire than does any other state.
B. The number of people who move out of Florida to accept employment in other states has increased over the past ten years.
C. There are far more local businesses in Florida that cater to tourists than there are local businesses that cater to retirees. 无关比较，还是说明会有不良的经济影响。
D. The total number of people who retired and moved to another state for their retirement has increased significantly over the past ten years. Total*%=the number of people who retired to F，应该以在F养老的人总数为衡量标准，因为百分比会因分母变大而变小，不具纵向参考性，横向比较才有参考性）
E. The number of people who left Florida when they retired to live in another state was greater last year than it was ten years ago.[D] 百分比和绝对数的换算作者: xiongbaobao 时间: 2010-10-20 15:28
GWD-3-Q38:
Kate: The recent decline in numbers of the Tennessee warbler, a North American songbird that migrates each fall to coffee plantations in South America, is due to the elimination of the dense tree cover that formerly was a feature of most South American coffee plantations.
浓密的树丛的消亡导致Warbler的数量减少
Scott: The population of the spruce budworm, the warbler’s favorite prey in North America, has been dropping. This is a more likely explanation of the warbler’s decline.
提供他因，是Warbler的prey的减少导致Warbler的减少
Which of the following, if true, most seriously calls Scott’s hypothesis into question?削弱第二人
A. The numbers of the Baltimore oriole, a songbird that does not eat budworms but is as dependent on South American coffee plantations as is the Tennessee warbler, are declining. 排除第二人提出的原因，第一人论断仍然成立
B. The spruce-budworm population has dropped because of a disease that can infect budworms but not Tennessee warblers.前提的原因，无关
C. The drop in the population of the spruce budworm is expected to be only temporary. 前提的情况无关
D. Many Tennessee warbler have begun migrating in the fall to places other than traditional coffee plantations.无关。结论的特殊性
E. Although many North American songbirds have declined in numbers, no other species has experienced as great a decline as has the Tennessee warbler.[A]结论的特殊性，无关作者: xiongbaobao 时间: 2010-10-20 15:28
GWD-4-Q14:
Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward. Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.
Which of the following, if true, most seriously weakens the guidebook writer’s argument?
A. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
B. Hotels built since 1930 can generally accommodate more guests than those built before 1930.无关
C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930. 支持
D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished. 言下之意1930年袋之前质量不好的carpentry都fall into disuse or be demolished了。异因同果
E. The average length of apprenticeship for carpenters has declined significantly since 1930.[D]支持作者: xiongbaobao 时间: 2010-10-20 15:28
GWD-5-Q15:
Lightbox, Inc., owns almost all of the movie theaters in Washington County and has announced plans to double the number of movie screens it has in the county within five years. Yet attendance at Lightbox’s theaters is only just large enough for profitability now and the county’s population is not expected to increase over the next ten years. Clearly, therefore, if there is indeed no increase in population, Lightbox’s new screens are unlikely to prove profitable.
Attendance 和population 决定要不要加screen
Which of the following, if true about Washington County, most seriously weakens the argument?
A. Though little change in the size of the population is expected, a pronounced shift toward a younger, more affluent, and more entertainment-oriented population is expected to occur.人口数不等于上座率
B. The sales of snacks and drinks in its movie theaters account for more of Lightbox’s profits than ticket sales do.
C. In selecting the mix of movies shown at its theaters, Lightbox’s policy is to avoid those that appeal to only a small segment of the moviegoing population.
D. Spending on video purchases, as well as spending on video rentals, is currently no longer increasing.
E. There are no population centers in the county that are not already served by at least one of the movie theaters that Lightbox owns and operates.[A]作者: xiongbaobao 时间: 2010-10-20 15:29
GWD-5-Q28:
Wind farms, which generate electricity using arrays of thousands of wind-powered turbines, require vast expanses of open land. County X and County Y have similar terrain, but the population density of County X is significantly higher than that of County Y. Therefore, a wind farm proposed for one of the two counties should be built in County Y rather than in County X.
前提，发电需要空旷空间
X的人口density大于Y的。Density仍旧是平均的概念
所以应该在Y建造发电。
Which of the following, if true, most seriously weakens the planner’s argument?
A. County X and County Y are adjacent to each other, and both are located in the windiest area of the state.
B. The total population of County Y is substantially greater than that of County X.
C. Some of the electricity generated by wind farms in County Y would be purchased by users outside the county.
D. Wind farms require more land per unit of electricity generated than does any other type of electrical-generation facility.
E. Nearly all of County X’s population is concentrated in a small part of the county, while County Y’s population is spread evenly throughout the country.[E]分布不均作者: xiongbaobao 时间: 2010-10-20 15:29
GWD-5-Q29:
Over the past five years, the price gap between name-brand cereals and less expensive store-brand cereals has become so wide that consumers have been switching increasingly to store brands despite the name brands’ reputation for better quality. To attract these consumers back, several manufacturers of name-brand cereals plan to narrow the price gap between their cereals and store brands to less than what it was five years ago.
知名品牌的价格太贵，
即使据称知名品牌的质量好，客户还是转向一般品牌
知名品牌决定降价来吸引顾客。
隐含假设：价格是顾客选择一般品牌的唯一理由。那么削弱就说还有其他理由。
Which of the following, if true, most seriously calls into question the likelihood that the manufacturers’ plan will succeed in attracting back a large percentage of consumers who have switched to store brands?
A. There is no significant difference among manufacturers of name-brand cereals in the prices they charge for their products.（反前提）
B. Consumers who have switched to store-brand cereals have generally been satisfied with the quality of those cereals.（在未含前提的情况下，提出他因）
C. Many consumers would never think of switching to store-brand cereals because they believe the name brand cereals to be of better quality. （无关）
D. Because of lower advertising costs, stores are able to offer their own brands of cereals at significantly lower prices than those charged for name-brand cereals. （无关）
E. Total annual sales of cereals—including both name-brand and store-brand cereals—have not increased significantly over the past five years. [B] （无关）作者: xiongbaobao 时间: 2010-10-20 15:29
GWD-6-Q20:
Five years ago, as part of a plan to encourage citizens of Levaska to increase the amount of money they put into savings, Levaska’s government introduced special savings accounts in which up to $3,000 a year can be saved with no tax due on the interest unless money is withdrawn before the account holder reaches the age of sixty-five. Millions of dollars have accumulated in the special accounts, so the government’s plan is obviously working.
Which of the following, if true, most seriously weakens the argument?
A. A substantial number of Levaskans have withdrawn at least some of the money they had invested in the special accounts.（取非不会支持）
B. Workers in Levaska who already save money in long-term tax-free accounts that are offered through their workplace cannot take advantage of the special savings accounts introduced by the government.（无关）
C. The rate at which interest earned on money deposited in regular savings accounts is taxed depends on the income bracket of the account holder. （无关）
D. Many Levaskans who already had long-term savings have steadily been transferring those savings into the special accounts. （从长期账户转存至特别账户，存款总量没有增加）注：即使长期账户的政府可控期限没有特别账户长，但特别账户不收利息税，此消彼长，不影响该选项的削弱力
E. Many of the economists who now claim that the government’s plan has been successful criticized it when it was introduced. （无关）作者: xiongbaobao 时间: 2010-10-20 15:30
GWD-6-Q21:
An overwhelming proportion of the most productive employees at SaleCo’s regional offices work not eight hours a day, five days a week, as do other SaleCo employees, but rather ten hours a day, four days a week, with Friday off. Noting this phenomenon, SaleCo’s president plans to increase overall productivity by keeping the offices closed on Fridays and having all employees work the same schedule—ten hours a day, four days a week。Which of the following, if true, provides the most reason to doubt that the president’s plan, if implemented, will achieve its stated purpose?
A. Typically, a SaleCo employee’s least productive hours in the workplace are the early afternoon hours.
B. None of the employees who work four days a week had volunteered to work that schedule, but all were assigned to it by their supervisors.
C. Working ten hours a day has allowed the most productive employees to work two hours alone each day in their respective offices relatively undisturbed by fellow employees. 最有效率的工人每天多工作两小时能提高生产力是因为不受其他员工干扰，若将所有员工的作息时间都调到一样就会使这个好处消失，弄巧成拙）
D. Employees at SaleCo are compensated not on the basis of how many hours a week they work but on the basis of how productive they are during the hours they are at work.
E. Those SaleCo employees who have a four-day workweek do not take any of their office work to do at home on Fridays.
选C
C提出这些职工多产的原因是每天有2个小时工作没受同事干扰。如果PRESIDENT的计划实行，这个多产的原因（没受同事干扰）就消失，PRESIDENT实行计划的目的（提高效率）就受挫。所以WEAKEN。
B说那些多产的职工是被迫的，但事实是他们产量高，他们被迫也好，自愿也好，也改变不了这个现实，反正他们产量最高。所以对PRESIDENT的计划起不了WEAKEN作用。作者: xiongbaobao 时间: 2010-10-20 15:30
GWD-7-Q17:
Of patients over 65 years old who survived coronary bypass surgery—a procedure widely prescribed for people with heart disease—only 75 percent benefited from the surgery. Thus it appears that for one in four such patients, the doctors who advised them to undergo this surgery, with its attendant risks and expense, were more interested in an opportunity to practice their skills and in their fee than in helping the patient.
75%的成活率----每四人中一人医生建议手术的目的在于手术费或锻炼技术。
Which of the following, if true, most seriously undermines the argument?
A. Many of the patients who receive coronary bypass surgery are less than 55 years old.
B. Possible benefits of coronary bypass surgery include both relief from troubling symptoms and prolongation of life.
C. Most of the patients in the survey decided to undergo coronary bypass surgery because they were advised that the surgery would reduce their risk of future heart attacks.
D. The patients over 65 years old who did not benefit from the coronary bypass surgery were as fully informed as those who did benefit from the surgery as to the risks of the surgery prior to undergoing it.（无关）
E. The patients who underwent coronary bypass surgery but who did not benefit from it were medically indistinguishable, prior to their surgery, from the patients who did benefit.反对隐含假设。方法不达目的
1。如果你能排除ABC，说明一定程度上明白了有关无关。
2。D的意思为收益和没收益的两批人都被告知手术的危险性。而结论是医生对没受益的动机不纯。显然D WEAKEN不了结论。医生完全可以说一套做一套。
3。E的意思为：收益和没收益两批人手术前在医疗上是分不出的。既然分不出，医生就无法对一批人动机好，另一批人动机不好。
Analysis: If the doctors had no idea whether a patient would benefit from the surgery prior to the surgery, as in the case of E, then it's baseless to accuse that the doctors performed the surgery only for their own interest, because it could very well be that the doctors recommended the surgery out of their true belief that it's best for the patient.作者: xiongbaobao 时间: 2010-10-20 15:30
GWD-7-Q30:
Printwell’s Ink Jet Division manufactures ink-jet printers and the ink cartridges they use. Sales of its ink-jet printers have increased. Monthly revenues from those sales, however, have not increased, because competition has forced Printwell to cut the prices of its printers. Unfortunately, Printwell has been unable to bring down the cost of manufacturing a printer. Thus, despite the increase in printer sales, the Ink Jet Division must be providing the company with much smaller than it used to.
公司自产自销自用IJ部门的打印机。销售增加，但是收入（销售减成本）没有增加，因为无法降低成本又必须减价
尽管打印机销售上升，IJ部门应该为公司提供更少的打印机
P*Sale-Cost=profit
Which of the following, if true, most seriously weakens the argument?
A. Ink-jet printers in regular use frequently need new ink cartridges, and Printwell’s printers only accept Printwell’s ink cartridges. printer的销量增加，由于它的printer只能采用自己的墨盒，所以，虽然printer的价格降低，但仍然有可能通过销售出去更多的墨盒而比以前更挣钱，所以这就weaken了结论。互补品
B. Unlike some competing companies, Printwell sells all of its printers through retailers, and these retailers’ costs account for a sizable proportion of the printers’ ultimate retail price.
C. Some printer manufacturers have been forced to reduce the sale price of their ink-jet printers even more than Printwell has.
D. In the past year, no competing manufacturer of ink-jet printers has had as great an increase in unit sales of printers as Printwell has.和别人比较没有意义，这里只关注公司内部成本收入等等的关系。不能横向比较
E. In the past year, sales of Printwell’s ink-jet printers have increased more than sales of any other type of printer made by Printwell.
C is irrelevant. Let me give you an example: A's salary is cut, therefore A's total income must be less. You can argue by saying B's income is cut even more because the original argument is not about comparing A and B. Back to the question. If the conclusion is that the company must be worse than other companies, C will be relevant.
这里是纵向比较,即自己和自己比.C是横向比较,和别的公司比.所以无关.作者: xiongbaobao 时间: 2010-10-20 15:30
GWD-8-Q3:
In the late 1980’s, the population of sea otters in the North Pacific Ocean began to decline. Of the two plausible explanations for the decline—increased predation by killer whales or disease—disease is the more likely. After all, a concurrent sharp decline in the populations of seals and sea lions was almost certainly caused by a pollution-related disease, which could have spread to sea otters, whereas the population of killer whales did not change noticeably.
不是killer whales而是disease减少了Sea Otters的数量。
因为其他动物减少也是因为disease然后传给SO
Killer whale数量不变。
Which of the following, if true, most seriously weakens the reasoning?
像这样的说一件事情可以有两种情况导致。文章中说是A而不是B导致。削弱可以提供原因说是B导致，或者提供其他同类事情证明是B导致，或者提供其他同类事情证明不是A导致（同音异果削弱）
A. Killer whales in the North Pacific usually prey on seals and sea lions but will, when this food source is scarce, seek out other prey.（因为海狮海豹受污染引起的疾病影响大量死去，所以killer whale就来捕食海獭造成其数量减少。）
B. There is no indication that substantial numbers of sea otters migrated to other locations from the North Pacific in the 1980’s.假设
C. Along the Pacific coast of North America in the 1980’s, sea otters were absent from many locations where they had been relatively common in former times. 证明事实正确
D. Following the decline in the population of the sea otters, there was an increase in the population of sea urchins, which are sea otters’ main food source. 无关
E. The North Pacific populations of seals and sea lions cover a wider geographic area than does the population of sea otters.[A]无关作者: xiongbaobao 时间: 2010-10-20 15:31
GWD-9-Q8:
Many large department stores in Montalia now provide shopping carts for their customers. Since customers using shopping carts tend to buy more than those without shopping carts, most of these stores are experiencing strong sales growth, while most other department stores are not. Therefore, in order to boost sales, managers of Jerrod’s, Montalia’s premier department store, are planning to purchase shopping carts and make them available to the store’s customers next month.
普遍现象：Cart多与消费者买得多同时发生，
M效仿为获得更多销售
Which of the following, if true, casts most doubt whether the managers’ plan, if implemented, will achieve its goal? 措施有效性。削弱，就是M迈Carts不能增加销售
A. Since most customers associate shopping carts with low-quality discount stores, Jerrod’s high-quality image would likely suffer if shopping carts were introduced.
B. Because the unemployment rate has declined to very low levels, Jerrod’s now has to pay significantly higher wages in order to retain its staff.
C. A number of department stores that did not make shopping carts available to their customers have had to close recently due to falling profits.无关
D. Shopping carts are not very expensive, but they generally need to be replaced every few years.
E. Stores that make shopping carts available to their customers usually have to hire people to retrieve the carts from parking areas.[A]
DE与文中的strong sales growth不符。Strong说明这些Sales Growth能弥补因多购买carts带来的成本。
理解答案A，关键透彻理解A的两层意思：1.J原来给人的印象是HIGH-QUALITY。2.SHOPPING CART给人的印象是low-quality.这两者的矛盾让人合理的想到引进shopping cart会使J的顾客去J的购买欲望受损，从而影响sales，即WEAKEN结论
E错在它只影响利润，结论讲的是SALE。无关作者: xiongbaobao 时间: 2010-10-20 15:31
GWD-9-Q28**:
Editorial in Krenlandian Newspaper:
Krenland’s steelmakers are losing domestic sales because of lower-priced imports, in many cases because foreign governments subsidize their steel industries in ways that are banned by international treaties. But whatever the cause, the cost is ultimately going to be jobs in Krenland’s steel industry. Therefore, it would protect not only steel companies but also industrial employment in Krenland if our government took measures to reduce cheap steel imports.
减少廉价钢材进口----保护钢材公司以及行业就业。
Which of the following, if true, most seriously weakens the editorial’s argument?
A. Because steel from Krenland is rarely competitive in international markets, only a very small portion of Krenlandian steelmakers’ revenue comes from exports.（无关）
B. The international treaties that some governments are violating by giving subsidies tosteelmakers do not specify any penalties for such violations.（无关）
C. For many Krenlandian manufacturers who face severe international competition in both domestic and export markets, steel constitutes a significant part of their raw material costs.（产业链成本控制：因为进口的钢材廉价，如果禁止，原料成本上升，加剧K国生产商面临的竞争）排除法也可
D. Because of advances in order-taking, shipping, and inventory systems, the cost of shipping steel from foreign producers to Krenland has fallen considerably in recent years. （无关）
E. Wages paid to workers in the steel industry in Krenland differ significantly from wages paid to workers in many of the countries that export steel to Krenland.[C] （无关）
原文推理：因为低价的进口钢原材挤掉了K地钢原材生产商的市场，使K地钢铁业失业增多。所以如果政府减少低价钢原材进口，就可减少失业。
C说K地钢原材价格构成了钢材加工品价格的主要部分。在这情况下，如果限制低价钢原材进口，就等于提高钢加工品价格，使钢材加工品竞争力减少，导致更多的失业。从而WEAKEN结论。作者: xiongbaobao 时间: 2010-10-20 15:31
GWD-10-Q40:
Insect infestations in certain cotton-growing regions of the world have caused dramatic increases in the price of cotton on the world market. By contrast, the price of soybeans has long remained stable. Knowing that cotton plants mature quickly, many soybean growers in Ortovia plan to cease growing soybeans and begin raising cotton instead, thereby taking advantage of the high price of cotton to increase their income significantly, at least over the next several years.
Which of the following, if true, most seriously weakens the plan’s chances for success?
A. The cost of raising soybeans has increased significantly over the past several years and is expected to continue to climb. （无关）
B. Tests of a newly developed, inexpensive pesticide have shown it to be both environmentally safe and effective against the insects that have infested cotton crops. 因为开发了价廉高效的农药。棉花的产量会上升，价格就会降低
C. In the past several years, there has been no sharp increase in the demand for cotton and for goods made out of cotton. （无关）
D. Few consumers would be willing to pay significantly higher prices for cotton goods than they are now paying. （取非不直接支持论点，消费者不一定要付很高价钱才是棉农获很大的利润，而且这里讲的是棉花，原料，而不是棉花制成的产品）
E. The species of insect that has infested cotton plants has never been known to attack soybean plants.（无关）
D错在：目前的COTTON价格已经能让棉农能增加他们的收入，目标已能达到。D表达的是人们不愿付比现在高的价格，对目前的价格并不排斥。所以棉农增加收入的目标还是能达到。WEAKEN不了结论。
B：a newly developed, inexpensive pesticide 可以effective against the insects that have infested cotton crops，削弱了原文的evidence，从而削弱原文的结论。作者: xiongbaobao 时间: 2010-10-20 15:32
GWD-11-Q27:
Mayor: Migrating shorebirds stop at our beach just to feed on horseshoe-crab eggs, a phenomenon that attracts tourists. To bring more tourists, the town council plans to undertake a beach reclamation project to double the area available to crabs for nesting.
Birdwatcher: Without a high density of crabs on a beach, migrating shorebirds will go hungry because shorebirds only eat eggs that a crab happens to uncover when it is digging its own nest.
Which of the following, if true, would provide the mayor with the strongest counter to the birdwatcher’s objection?
A. Every year a certain percentage of crabs are caught by fishermen as bait for eel traps.
B. Horseshoe crabs are so prolific that given favorable circumstances也就是说这种蟹只要给够大的空间他就能迅速繁殖。也就不存在Birdwatcher反对前面一个人的假设。 their numbers increase rapidly. 方案可行性
C. On average, tourists who come to the town in order to watch birds spend more money there than tourists who come for other purposes.
D. The additional land made available by the reclamation project will give migrating shorebirds more space.
E. Some of the migrating shorebirds make only one stop during their migration form South America to Canada.作者: xiongbaobao 时间: 2010-10-20 15:32
GWD-11-Q38:
Unprecedented industrial growth in the country of Remo has created serious environmental problems because factories there lack adequate pollution-control systems. Remo is developing a clean growth plan that includes environmental regulations that will require the installation of such systems. Since no companies in Remo currently produce pollution-control systems, the plan, if implemented, will create significant opportunities for foreign exporters to market pollution-control systems.
Which of the following, if true, most seriously weakens the argument?
A. The clean growth plan will provide tax incentives for local businesses to develop and manufacture pollution-control devices. 这样一来外国出口商的机会就不那么大了。程度削弱
B. Foreign exporters would provide factory-trained technicians to maintain the pollution-control systems sold to Remo.
C. Industrial lobbyists sponsored by local businesses in Remo are trying to prevent the implementation of the government regulations.
D. The regulations that Remo plans to implement are much less strict than those in neighboring nations.
E. Pollution in Remo has caused serious health problems for workers, contributing to a significant increase in the number of workdays lost to illness.
A为答案。该题其他易排除，AC易混。C错在原文的结论是建立在 if implemented上，如果还没有 implemented，则不是该结论所要说的。C说的就是没 implemented的事。A说虽然地方没生产这系统的，但税收机制会促使他们去生产，故WEAKEN原文结论的create significant opportunities for foreign exporters 。作者: xiongbaobao 时间: 2010-10-20 15:33
GWD-11-Q41:
Charcoal from a hearth site in Colorado, 2,000 miles south of Alaska, is known to be 11,200 years old. Researchers reasoned that, since glaciers prevented human migration south from the Alaska-Siberia land bridge between 18,000 and 11,000 years ago, humans must have come to the Americas more than 18,000 years ago.
Which of the following pieces of new evidence would cast doubt on the conclusion drawn above?
A. Using new radiocarbon dating techniques, it was determined that the charcoal from the Colorado site was at least 11,400 years old.
B. Another campsite was found in New Mexico with remains dated at 16,000 years old.
C. A computer simulation of glacial activity showed that it would already have been impossible for humans to travel south overland from Alaska 18,500 years ago.
D. Using new radiocarbon dating techniques, it was proved that an ice-free corridor allowed passage south from the Alaska-Siberia land bridge at least 11,400 years ago.
E. Studies of various other hunting-gathering populations showed convincingly that, once the glaciers allowed passage, humans could have migrated from Alaska to Colorado in about 20 years.
这是WEAKEN题。原文的推理是：木炭是11200年前的（即11200年前由人类活动），而在11000和18000年前之间，冰川在人阻止人类迁到北美。所以人类是在18000年前到达的。其前提是在11000和18000之间，人类无法通过其它途径到达北美。D提出了另外的途径。所以WEAKNE结论。
B错在时间不是campsite的时间，而是REMAINS的时间，这个remains的时间并不代表有人类活动的时间。比如这个remains是什麽更早的古物，是人类从别的地方带来的。所以它的时间不代表人类在北美活动的时间。B错也并不是因为New Mexico无关。B想混淆大家的是：在11000和18000这段时间里，new mexico 也有人住。（因为new mexico 在 colorado的南面，ETS想误导大家16000年时有人通过Alaska-Siberia land bridge）但B并不能weaken原推论。因为即使new mexico 16000有人住，这些人也可能是在18000之前就通过Alaska-Siberia land bridge 搬过来的。
E 人类迁移时间和原文无关。原文只是说11000到18000期间通道都被冰川冰冻，并没说期间有多久解冻，人类可通过作者: xiongbaobao 时间: 2010-10-20 15:33
GWD-12-Q2:简单
Scientists are discussing ways to remove excess carbon dioxide from the atmosphere by increasing the amount that is absorbed by plant life. One plan to accomplish this is to establish giant floating seaweed farms in the oceans. When the seaweed plants die, they will be disposed of by being burned for fuel.
Which of the following, if true, would indicate the most serious weakness in the plan above?
A. Some areas of ocean in the Southern Hemisphere do not contain sufficient nutrients to support large seaweed farms.
B. When a seaweed plant is burned, it releases an amount of carbon dioxide comparable to the amount it has absorbed in its lifetime.
C. Even if seaweed farms prove effective, some people will be reluctant to switch to this new fuel.
D. Each year about seven billion tons of carbon dioxide are released into the atmosphere but only about five billion tons are absorbed by plant life.
E. Seaweed farms would make more money by farming seaweed to sell as nutritional supplements than by farming seaweed to sell as fuel.作者: xiongbaobao 时间: 2010-10-20 15:34
GWD-12-Q15:
FastMart, a convenience store chain, is planning to add pancake syrup to the items it sells. FastMart stores do not have shelf space to stock more than one variety of syrup. Surveys of FastMart customers indicate that one-fourth of them prefer low-calorie syrup, while three-fourths prefer regular syrup. Since FastMart’s highest priority is to maximize sales, the obvious strategy for it is to stock regular syrup.
找stock regular syrup不能maximize sales的
Which of the following, if true, most seriously weakens the argument?
A: People buying pancake syrup at convenience stores, unlike those buying it at supermarkets, generally buy it only a few times.
B. People who prefer low-calorie syrup generally use about the same amount of syrup on their pancakes as those who prefer regular syrup.
C. Regular syrup does not sell for a higher price per unit than low-calorie syrup.
D. In general, customers who prefer regular syrup will buy low-calorie syrup if regular is unavailable, but those who prefer low-calorie will not buy regular syrup. (在没有自己要的syrup时，喜欢regular的会退而求其次，喜欢low-c的就不买了)
E. Sales of syrup are not expected to account for a large proportion of total dollar sales at the average FastMart store.
regular syrup=3/4 customer
low calorie syrup= 100% customer作者: xiongbaobao 时间: 2010-10-20 15:34
GWD-12-Q16:
Certain genetically modified strains品种 of maize玉米 produce a natural insecticide that protects against maize-eating insects. The insecticide occurs throughout the plant, including its pollen. Maize pollen is dispersed by the wind and often blows onto milkweed plants that grow near maize fields. Caterpillars of monarch butterflies feed exclusively on milkweed leaves. When, in experiments, these caterpillars were fed milkweed leaves dusted with pollen from modified maize plants, they died. Therefore, use of the modified maize inadvertently imperils monarch butterflies.
Which of the following, if true, most seriously weakens the argument?
吃milkweed上玉米花粉导致蝴蝶幼虫死亡。
A. Per unit of volume, the natural insecticide produced by the genetically modified maize plants is less toxic to insects than are many commercial insecticides commonly used on maize plants.
B. Standard weed-control practices that have been used by farmers for decades have largely eliminated milkweed plants from certain areas where monarch-butterfly caterpillars were once common.
C. The experiments showed that the caterpillars were not harmed by contact with the pollen from the genetically modified plants unless they ingested it.
D. The maize-eating insects that the natural insecticide protects against do not feed on the pollen of the maize plant.结论的特殊性这里讨论蝴蝶。
E. Airborne maize pollen tends to collect on the middle leaves of milkweed plants and monarch caterpillars feed only on the plant’s tender upper leaves.作者: xiongbaobao 时间: 2010-10-20 15:35
GWD-13-Q5*:
Vorland’s government is planning a nationwide ban on smoking in restaurants. The objection that the ban would reduce restaurants’ revenues is ill founded. Several towns in Vorland enacted restaurant smoking restrictions five years ago. Since then, the amount the government collects in restaurant meal taxes in those towns has increased 34 percent, on average, but only 26 percent elsewhere in Vorland. The amount collected in restaurant meal taxes closely reflects restaurants’ revenues.
Which of the following, if true, most undermines the defense of the government’s plan?
A. When the state first imposed a restaurant meal tax, opponents predicted that restaurants’ revenues would decline as a result, a prediction that proved to be correct in the short term.
B. The tax on meals in restaurants is higher than the tax on many other goods and services.
C. Over the last five years, smoking has steadily declined throughout Vorland.
D. In many of the towns that restrict smoking in restaurants, restaurants can maintain separate dining areas where smoking is permitted.这里weaken的不是结果，而是证据与结果间的因果关联性
E. Over the last five years, government revenues from sales taxes have grown no faster in the towns with restaurant smoking restrictions than in the towns that have no such restrictions.
原文推理：禁止在饭店吸烟——》预期饭店收入会减少——》事实上饭店餐税增加（收入增加）——》禁止在饭店吸烟不会降低饭店收入
D说：在大多数的地方的饭店可以维持吸烟，因此饭店收入增加和禁止吸烟不能形成有效的因果关系（削弱）
同意D。
1。结论：禁烟对。证据：自从五年前部分镇禁烟后，restaurants收入增长大于没禁烟的镇（meal taxes 增长，而meal taxes 又closely反映收入的增长）。它隐含的意思是禁烟使收入增长，从而说明禁烟是对的。D说在禁烟的小镇，restaurants仍保留吸烟区，允许吸烟。说明不是禁烟使restaurants的收入增加。WEAKEN原文证据对结论的证明力。
2。E不但错在前面所说的sales taxes 和原文无关（原文是meal taxes ，而且已说meal taxes 准确的反映收入 ），而且原文说的是对restaurants的收入的影响，E说的是镇的税收的变化，原文没有任何信息使人想到这个镇的税收的变化是restaurants导致的还是别的行业导致的。故E不能WEAKEN原文的结论。作者: xiongbaobao 时间: 2010-10-20 15:35
14
In 1983 Argonia’s currency, the argon, underwent a reduction in value relative to the world’s strongest currencies. This reduction resulted in a significant increase in Argonia’s exports over 1982 levels. In 1987 a similar reduction in the value of the argon led to another increase in Argonia’s exports. Faced with the need to increase exports yet again, Argonia’s finance minister has proposed another reduction in the value of the argon.
本币贬值----出口增加。
重复操作
Which of the following, if true, most strongly supports the prediction that the finance minister’s plan will not result in a significant increase in Argonia’s exports next year?
A. The value of the argon rose sharply last year against the world’s strongest currencies.
B. In 1988 the argon lost a small amount of its value, and Aronian exports rose slightly in 1989.
C. The value of Argonia’s exports was lower last year than it was the year before.
D. All of Argonia’s export products are made by factories that were operating at full capacity last year, and new factories would take years to build.方案不可行。就算想增加也没有能力增加了
E. Reductions in the value of the argon have almost always led to significant reductions in the amount of goods and services that Argonians purchase from abroad.作者: xiongbaobao 时间: 2010-10-20 15:36
15.
Healthy lungs produce a natural antibiotic that protects them from infection by routinely killing harmful bacteria on airway surfaces. People with cystic fibroses, however, are unable to fight off such bacteria, even though their lungs produce normal amounts of the antibiotic. Since the fluid on airway surfaces in the lungs of people with cystic fibrosis bas an abnormally high salt concentration, scientists hypothesize that in high salt environments the antibiotic becomes ineffective at killing harmful bacteria.
高盐密度导致抗生体不能消灭有害细菌
削弱方法：举反例：没有高盐密度抗生体也不能消灭有害细菌
抗生体不能消灭有害细菌导致高盐密度
。。。
Which of the following, if it were obtained as an experimental result, would most decisively undermine the scientists’ hypothesis?
A. Healthy lungs in which the salt concentration of the airway-surface fluid has been substantially increased are able to reestablish their normal salt concentration within a relatively short period of time.
B. The antibiotic produced by the lungs is effective at killing harmful bacteria even when salt concentrations are below levels typical of healthy lungs.
C. The salt concentration of the airway-surface fluid in the lungs of people who suffer from cystic fibrosis tends to return to its former high levels after having been reduced to levels typical of healthy lungs.
D. The lungs of people who suffer from cystic fibrosis are unable to fight off harmful bacteria even when the salt concentration is reduced to levels typical of healthy lungs.
E. The salt concentration in the airway-surface fluid of people whose lungs produce lower-than-average amounts of the antibiotic is generally much lower than that typical of healthy lungs.作者: xiongbaobao 时间: 2010-10-20 15:36
GWD29-Q9:
Manatees, aquatic mammals inhabiting Florida’s rivers and coastal waters, swim close to the surface and are frequently killed in collisions with boats. To address the problem, boat traffic in manatee-populated waters is being required to maintain very low speeds. Unfortunately, manatees are unable to hear low-pitched sounds and a boat’s sound lowers in pitch as the boat slows. Therefore, this approach may in fact make things worse rather than better.
Which of the following, if true, casts most doubt on the conclusion?
A. The areas where boats would have to maintain low speeds were decided partly on the basis of manatee-population estimates and partly from numbers of reported collisions between manatees and boats.
B. Because the water hyacinth that manatees feed on grows best in water that is nearly still, water hyacinth beds can be disturbed or damaged by fast-moving boat traffic.
C. Over the last several decades, boat traffic in Florida’s coastal waters has been increasing almost continuously and now represents the greatest threat to the endangered manatee population.
D. The sound of a boat engine generally travels much further under water than it does through the air.
E. When experimenters exposed manatees to the recorded sounds of boats moving at various speeds, the creatures were unable to discern the sounds over normal background noise.作者: xiongbaobao 时间: 2010-10-20 15:36
T-4-Q21粗心
The OLEX Petroleum Company has recently determined that it could cut its refining costs by closing its Grenville refinery and consolidating all refining at its Tasberg refinery. Closing the Grenville refinery, however, would mean the immediate loss of about 1,2000 jobs in the Grenville area. Eventually the lives of more than 10,000 people would be seriously disrupted. Therefore, OLEX’s decision, announced yesterday, to keep Grenville open shows that at OLEX social concerns sometimes outweigh the desire for higher profits.
又是成本收益
要证明OLEX决定不关G是出于利润的考虑而不是社会责任
Which of the following, if true, most seriously undermines the argument given?
A. The Grenville refinery, although it operates at a higher cost than the Tasberg refinery, has nevertheless been moderately profitable for many years.这里如果是significant就对了
B. Even though OLEX could consolidate all its refining at the Tasberg plant, doing so at the Grenville plant would not be feasible.
C. The Tasberg refinery is more favorably situated than the Grenville refinery with respect to the major supply routes for raw petroleum.
D. If the Grenville refinery were ever closed and operations at the Tasberg refinery expanded, job openings at Tasberg would to the extent possible be filled with people formerly employed at Grenville.
E. Closure of the Grenville refinery would mean compliance, at enormous cost, with demanding local codes regulating the cleanup of abandoned industrial sites.关闭后成本反而大
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