逻辑错题帖~~

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52. Birds need so much food energy to maintain their body temperatures that some of them spend most of their time eating. But a comparison of a bird of a seed-eating species to a bird of a nectar-eating species that has the same overall energy requirement would surely show that the seed-eating bird spends more time eating than does the nectar-eating bird, since a given amount of nectar provides more energy than does the same amount of seeds

The argument relies on which one of the following questionable assumptions

A.        Birds of different species do not generally have the same overall energy requirements as each other
B.        The nectar-eating bird does not sometimes also eat seeds
C.        The time it takes for the nectar-eating bird to eat a given amount of nectar is not longer than the time it takes the seed-eating bird to eat the same amount of seeds
D.        The seed-eating bird does not have a lower body temperature than that of the nectar-eating bird
E.        The overall energy requirements of a given bird do not depend on factors such as the size of the bird, its nest-building habits; and the climate of the region in which it lives
答案：C

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Nectar鸟和seed鸟需要能量一样多，但nectar食物单个能量大，所以nectar鸟吃的数量少。结论：nectar鸟吃东西花的时间少。 使以上必然成立的条件（assumption)是nectar鸟一定吃的更快，不然还是有可能花的时间比seed鸟多。和C相反，所以c questionable。---- seanql

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53. When investigators discovered that the director of a local charity had repeatedly overstated the number of people his charity had helped, the director accepted responsibility for the deception. However, the investigators claims that journalists were as much to blame as the director was for inflating the charity’s reputation, since they had naively accepted what the director told them, and simply reported as fact the numbers he gave them.

Which one of the following principles, if valid, most helps to justify the investigators’ claim

A.        Anyone who works for a charitable organization is obliged to be completely honest about the activities of that organization.
B.        Anyone who knowingly aids a liar by trying to conceal the truth from others is also a liar.
C.        Anyone who presents as factual a story that turns out to be untrue without first attempting to verify that story is no less responsible for the consequences of that story than anyone else is.
D.        Anyone who lies in order to advance his or her own career is more deserving of blame than someone who lies in order to promote a good cause.
E.        Anyone who accepts responsibility for a wrongful act that he or she committed is less deserving of blame than someone who tries to conceal his or her own wrongdoing.
答案：C

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72. A gas tax of one cent per gallon would raise one billion dollars per year at current consumption rates. Since a tax of fifty cents per gallon would therefore raise fifty billion dollars per year, it seems a perfect way to deal with the federal budget deficit. This tax would have the additional advantage that the resulting drop in the demand for gasoline would be ecologically sound and would keep our county from being too dependent on foreign oil producers.

Which one of the following most clearly identifies an error in the author’s reasoning?

A.The author cites irrelevant data.
B.The author relies on incorrect current consumption figures.
C.The author makes incompatible assumptions.
D.The author mistakes an effect for a cause.
E.The author appeals to conscience rather than reason

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参考答案：C
思路：作者得出的结论有两个，1是提高汽油税率，可以同比提高税收所得，这一结论的前提条件是，汽油的消费量不受税率影响；2是提高税率可以降低对汽油的消费需求，这一结论的假设条件与前一结论的假设条件是互相矛盾的，因此显而易见，C正确。

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42. Crowding on Mooreville’s subway frequently leads to
delays, because it is diffi cult for passengers to exit
from the trains. Subway ridership is projected to
increase by 20 percent over the next 10 years. The
Mooreville Transit Authority plans to increase the
number of daily train trips by only 5 percent over the
same period. Offi cials predict that this increase is
suffi cient to ensure that the incidence of delays due
to crowding does not increase.
Which of the following, if true, provides the strongest
grounds for the offi cials’ prediction?
(A) By changing maintenance schedules, the Transit
Authority can achieve the 5 percent increase
in train trips without purchasing any new
subway cars.
(B) The Transit Authority also plans a 5 percent
increase in the number of bus trips on routes
that connect to subways.
(C) For most commuters who use the subway
system, there is no practical alternative public
transportation available.
(D) Most of the projected increase in ridership is
expected to occur in off-peak hours when trains
are now sparsely used.
(E) The 5 percent increase in the number of train
trips can be achieved without an equal increase
in Transit Authority operational costs.

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题目问的是，为什么乘客人数增加百分之二十，而只需要增加地车班次百分之五就够了。D中因为增加的乘客主要集中在off-peak hour时段,这个时段原本是有许多趟列车没有得到充分使用 (sparsely used),所以在人数增加20%的情况下,列车数只要增加5%就够.
估计不少筒子在做这题之前，犯了了个先入为主的错误，认为减少拥挤就得要在高峰期增加车次。
但是实际情况不是这样的。 以我以前住的地方为例。早上高峰期以外的车次极少，结果上班族，旅行者，退休的老头老太，学生，全部都挤在那一段时间里，场面极为混乱。后来在非高峰期增加了班次，那些退休的老头老太，以及旅行者等都有了其他选择，而上班族和学生有的也会选择更早的班次来躲避高峰期，结果是皆大欢喜。这道题目我让我最迷惑的地方其实在问题里面。他问的是 strongest grounds，以中国人的逻辑，立刻就开始找背景原因了。可惜该选项比起传统意义上的ground，更像是method。如果问题是问有most Effective means（最有效的手段）的话，可能正确率就上去了。(解释来源：K满分的NN们)

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Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the Arctic and are displacing birds of less vigorous species.  Although snow geese are a popular quarry for hunters in the southern regions where they winter, the hunting season ends if and when hunting has reduced the population by five percent, according to official estimates.  Clearly, dropping this restriction would allow the other species to recover.

Which of the following, if true, most seriously undermines the argument?

A.    Hunting limits for snow geese were imposed many years ago in response to a sharp decline in the population of snow geese.
B.    It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.
C.    The number of snow geese taken by hunters each year has grown every year for several years.
D.    As their population has increased, snow geese have recolonized wintering grounds that they had not used for several seasons.
E.    In the snow goose’s winter habitats, the goose faces no significant natural predation.

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此题CR暗含的一个推理是：restriction---->more SG---->threaten other species ,只有B选项指出不是限令导致了雪鹅数量的增长，所以weaken.

更详细点分析：
B.It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.
自限令使对雪鹅的扑杀提前结束已经很多年了，但雪鹅数量是最近才又一个急剧增长，并对其他鸟类造成威胁，说明并不是限令造成了雪鹅数量的增长，因此取消限令也不会造成其他鸟类物种数量的回升。

这里最关键的是看清题目里的recent sharp increases 和选项里的it had been many year   (解释来源：k满分）

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Because visual inspection cannot reliably distinguish certain skin discolorations from skin cancers, dermatologists at clinics have needed to perform tests of skin tissue taken from patients. At Westville Hospital, dermatological diagnostic costs were reduced by the purchase of a new imaging machine that diagnoses skin cancer in such cases as reliably as the tissue tests do. Consequently, even though the machine is expensive, a dermatological clinic in Westville is considering buying one to reduce diagnostic costs.
Which of the following would it be most useful for the clinic to establish in order to make its decision?
A. Whether the visits of patients who require diagnosis of skin discolorations tend to be shorter in
duration at the clinic than at the hospital
B. Whether the principles on which the machine operates have been known to science for a long time
C. Whether the machine at the clinic would get significantly less heavy use than the machine at the
hospital does
D. Whether in certain cases of skin discoloration, visual inspection is sufficient to make a diagnosis of
skin cancer
E. Whether hospitals in other parts of the country have purchased such imaging machines