【每日逻辑练习第二季】【1-1】

daisyの小夢想

在我们CR小分队的共同努力和老大的鼎力支持下，每日逻辑练习终于完成了改进工作，我们都小激动了一翻。
正如我们的序言所言，“坚持梦，做更好的CR”，每日逻辑练习追求的是不断进步，不断成长为更好的练习模式。
所以，非常期待广大XDJM们一起练习、一起钻研，用共同的脑力结晶创造更好的CR!


跟帖做题方法请见：
http://forum.chasedream.com/GMAT_CR/thread-613902-1-1.html





【精练】
1. Carl is clearly an incompetent detective. He has
solved a smaller percentage of the cases assigned to
him in the last 3 years—only 1 out of 25—than any
other detective on the police force.
Which one of the following, if true, most seriously
weakens the argument above?
--BIBLE WEAKEN NO.1
(A) Because the police chief regards Carl as the
most capable detective, she assigns him only
the most difficult cases, ones that others have
failed to solve.
(B) Before he became a detective, Carl was a
neighborhood police officer and was highly
respected by the residents of the
neighborhood he patrolled.
(C) Detectives on the police force on which Carl
serves are provided with extensive resources,
including the use of a large computer
database, to help them solve crimes.
(D) Carl was previously a detective in a police
department in another city, and in the 4 years
he spent there, he solved only 1 out of 30
crimes.
(E) Many of the officers in the police department in
which Carl serves were hired or promoted
within the last 5 years.





【逻辑链】
2.
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?
--PREP07 CR1 NO.1

(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.





3.
Economist:  On average, the emergency treatment for an elderly person for injuries resulting from a fall costs $11,000.  A new therapeutic program can significantly reduce an elderly person's chances of falling.  Though obviously desirable for many reasons, this treatment program will cost $12,500 and thus cannot be justified.


Which of the following, if true, most seriously undermines the conclusion of the argument?
--PREP07 CR1 NO.2

(A) Among elderly people who had followed the program for only a few months, the number of serious falls reported was higher than it was for people who had followed the program for its recommended minimum length of one year.
(B) Falls resulting in serious injuries are less common among elderly people living in nursing homes than they are among elderly people who live alone at home.
(C) A frequent result of injuries sustained in falls is long-term pain, medication for which is not counted among the average per-person costs of emergency treatment for elderly people's injuries from such falls.
(D) The new therapeutic program focuses on therapies other than medication, since overmedication can cause disorientation and hence increase the likelihood that an elderly person will have a serious fall.
(E) A significant portion of the cost of the new therapeutic program is represented by regular visits by health care professionals, the costs of which tend to increase more rapidly than do those of other elements of the program.


4.
The prairie vole, a small North American grassland rodent, breeds year-round, and a group of voles living together consists primarily of an extended family, often including two or more litters.  Voles commonly live in large groups from late autumn through winter; from spring through early autumn, however, most voles live in far smaller groups.  The seasonal variation in group size can probably be explained by a seasonal variation in mortality among young voles.


Which of the following, if true, provides the strongest support for the explanation offered?
--PREP07 CR1 NO.3

(A) It is in the spring and early summer that prairie vole communities generally contain the highest proportion of young voles.
(B) Prairie vole populations vary dramatically in size from year to year.
(C) The prairie vole subsists primarily on broad-leaved plants that are abundant only in spring.
(D) Winters in the prairie voles' habitat are often harsh, with temperatures that drop well below freezing.
(E) Snakes, a major predator of young prairie voles, are active only from spring through early autumn.


5.
A popular beach has long had a dolphin feeding program in which fish are given to dolphins several times a day; many dolphins get as much as half of their food each day there.  Although dolphins that first benefit from the program as adults are healthy and long-lived, their offspring have a lower life expectancy than offspring of dolphins that feed exclusively in the wild.


Which of the following, if true, most helps to explain the lower life expectancy of offspring of dolphins feeding at the beach compared to other young dolphins?
--PREP07 CR1 NO.4

(A) Sharks that prey on dolphins are less common in the open seas off the beach than in many other areas of the open seas where dolphins congregate.
(B) Many of the adult dolphins that feed at the beach are females that nurse their offspring there.
(C) The fish given to the dolphins at the beach are the same types of fish that dolphins typically catch in the wild.
(D) Many dolphins that feed at the beach with their offspring come to the beach only a few times a month.
(E) Adult dolphins that feed at the beach spend much less time teaching their offspring how to catch fish in the wild than do other adult dolphins.

Miaaah

因果推理型
结果（前提）：过去三年Carl做的case比其他同事少
因（结论）：Carl是一个incompetent的侦探
CQ：相关性削弱&找出结果的真正原因（case做的少的真正原因（除了工作能力））1. 在过去三年做的少，可能之前做的多，上班时间少很多，但效率高；
2.他的competence和case数量没有关系；case做的少但是case难度高A选项；
3.在一个高水平的团队里面，跟别人比很差，但是实际上不算差的
A 找出了case做的少的真正原因--case难度大--工作能力强
B.无关选项，没办法说明他的工作能力与case做的少的关系；也不能提供case少的真正原因
C.无关选项，一点关系都没有
D.在其他地方也做的少，增强结论--工作能力差
无关选项
E.类比推理
前提：实验室和自然环境下都有fullerene；实验室的fullerene产生于一个温度压力的特殊条件下
结论：自然环境也是在相同条件下才能有fullerene 推测当时的自然环境与实验室产生的该物质环境一致

CQ：削弱相关性&引入第三种可能
1.实验室的产生环境与自然条件下产生环境不能进行类比，存在其他很多差异（其他微生物影响啊等等，除了温度和压力因素外）
2.该物质的产生环境≠当时自然环境 可能该物质不是在当时自然环境状态下产生的（对应B选项 可能来自其他小行星）

A 无关，没有涉及到核心推理逻辑关系（该物质的实验室产生状态--自然界产生状态--当时的地质状态）
B 给予第三种可能性
C 无关
D无关
E 加强
因果推理：
因（前提）：摔倒治疗花的钱少于预防摔倒的项目费用
果（结论）：这个项目不划算

CQ：这个cost是否是有效的？平均值？两个费用是否可比？
可能摔倒的真实花费大于项目费用（项目费用固定 但是治疗费用是个平均值）
除了治疗费用，摔倒造成了其他非直接经济损失（误工费，调养费-C选项）

A 项目长短 无关选项
B 摔倒的人居住地 无关选项
C 长期药物花销没有计入摔倒的费用，正确选项
D 提出了program的另一个好处，但是不能直接削弱该arguement的逻辑推理-- program花销贵所以不值得（如果将好处量化成经济效益，比如program注重therapy 所以之后在药物上花的钱会更少，就可以削弱该结论）
E 无关选项
因果推理
前提（果）：秋冬这种鸟很多数量地聚集，到了春天和早秋这段时间，数量比较少
结论（因）：这种数量变化与季节性死亡率变化有关

CQ：削弱相关性&找出真正原因
数量变化跟死亡率变化无关（出生率变化 死亡率不变； 出生率死亡率都不变，其他原因影响群体活动）
影响群体死亡率的因素不发生改变（捕食者、气候等）
可能是有目的性的减少群体数量（避免捕食者攻击 成熟了之后单飞）

A.这里不要想太多 vole 的proportion与题目的推理无关 不能解释死亡率与群体数量变化的关系 （可能是死亡率增加导致年轻比例的增多 也可能是出生率增加年轻比例上升 那么导致应该有更多的voles）
B 无关选项
C 无关选项
D 跟group size & 死亡率都无关
E 捕食者的季节性导致-死亡率的季节性--group size 的季节性 正确选项
类比推理--反向 不同的原因
果：跟野生dolphin相比，被喂养的dolphin活一样长，但是下一代的寿命却很短
因：？

CQ: 被喂养的鱼影响了下一代的dolphin健康，所以短命；这种喂养机制影响了第一代和第二代本身（身体不好 能力不强）；影响了第二代的生存环境（更多的捕食者 竞争者）
A 无关选项 没有体现出第一代和第二代的寿命区别
B 无关选项 只是在那里喂养 没有说影响寿命的因素
C 这里是削弱 鱼也没区别 不能解释这个difference
D 无关 没解释野生和被喂养的区别
E给出一个差距点，解释了difference

anycoa

逻辑第二题和第三题做错了，我错选为B和D，做了一个逻辑链，发现分析错题好有意思啊哈哈哈。

Lincy123

第二题改正：
b) "some" is not preferred.
d) the structure of natural f is different with lab f, so they are not comparable. correct.

Lincy123

C: C is an incompetent detective
P: C solved a smaller percentage of the cases in last three yrs than others

Guess: quantity can’t equal to quality. Maybe those cases C solved are big cases, while ohters’ are small cases.
a)        Similar with the guess, correct
b)        Irrelevant.
c)        Irrelevant
d)        Irrelevant, only shows that the number of cases C solved is small
e)        Irrelevant

bg: f were first found in the lab, F have been found in nature
P; f require distinctive conditions of T and P
C: the discovery can be used to evaluate the state of the Earth’s crust at the time f were formed

Guess: the condition in lab is different with condition in Earth crust

a)        Irrelevant, only emphasize that the experiment is careful
b)        F also found in meteorite. It means the condition they evaluate in the lab may refer to the meteorite, not the earth crust. correct
c)        Explain the form of ms, irrelevant
d)        Explain the structure of f, irrelevant
e)        Explain the condition that s is formed, irrelevant

Bg: elderly person injured from falling cost 11000. A new program can reduce the chance of falling.
P: the cost of the program is 12500
C: the program is not justified

Guess: elderly people may fall more than one more time. And the number of falling maybe larger than the number of program conduction

a)        The number of fall even higher after program. Strengthen
b)        Explain the nursing home is better, irrelevant
c)        The long-term pain in falls is not counted in treatment. It means that the actual cost is more than 11000. correct
d)        Explain why program focus on therapies. Irrelevant
e)        The program’s cost of visits by professionals is increasing. Strengthen.

Bg: pv live in family, including 2 or more litters.
C: V live in large group from late autumn to winter; live in small group from spring to autumn
P: is related to the mortality among young v

Guess: the predator of v is in large number in spring. The food of young v is less in spring.

a)        in spring the proportion of young v is high. Irrelevant
b)        population vary year to year, but the question is focus on seasons, irrelevant
c)        the food is abundant in spring, is contradictory to the passage, weaken.
d)        Only explain winter habitat, can’t see the difference among seasons. Irrelevant
e)        Correct

Bg: a beach had a dolphin feeding program to give dolphin fish.
C: the offspring of the first benefit dolphin have a lower life span than wild dolphin
Ask p?

Guess: fed dolphin lose the ability to catch fish, and can’t live in the ocean.

a)        Predator are less common in the open seas off the beach. Conflict to conclusion. Weaken.
b)        Fed dolphin are most female and nurse offspring at the beach. Irrelevant
c)        Fish given and fish in the sea are the same. Irrelevant.
d)        Dolphin come to beach a few times a month. Irrelevant
e)        correct

小歇歇啊

看一下！               

LJLlilili

看一下！               

小火焰

daisyの小夢想 发表于 2011-11-19 20:36
Key答案藏在此哦哈) A DCEE【精练题解释】Answer choice (A): This is the correct answer. We discover  ...

Mark一下！               

云栈

1.        20s
P: He has solved a smaller percentage of the cases assigned to him in the last 3 years-only 1 out of 25-than any other detective on the police force.
C: Carl is clearly an incompetent detective.
推测：给carl分配的任务难度比别人高；carl完成任务的环境比别人差
选项分析：选A 因为carl的任务比别人难，所以他完成度比别人低，并不代表他比别人差
B）当警察的时候respect by others不代表他的侦探能力比较强
C) opposite answer 警局提供了更好的资源反而支持了题中的conclusion
D）opposite answer Carl之前的经历更加说明他没有能力
E) 无关，警局很多人被晋升反而说明carl可能比别人差

2.        33s
P：Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure.
C: 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.
B：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.
推测：天然发现的可能不方便研究，采集难度高；【这题不太确定，看答案发现选错了
选项分析：选E
A) shungite中含有fullerenes是题目中已有的信息
B) fullerenes存在于陨石中，support argument
C) shungite自身的成分不重要
D) 说明天然形成的fullerenes和实验室发现的不同，但是不能undermine argument
E) 说明shungite的形成难度大，也说明fullerenes不好形成

3.        50s
P: A new therapeutic program can significantly reduce the elderly person’s chances of falling, this treatment program will cost $12500. The emergency treatment for an elderly person for injuries resulting from a fall costs $11,000.
C: this treatment program cannot be justified.
推测：摔倒的老人除了紧急治疗费之外，后续还要花费别的费用；很多人宁愿花多的钱预防摔跤，也不愿意花少的钱治疗摔跤。
选项分析：选C
A)        与program的花费无关，并不能说明更多人愿意参与这个program
B)        Falls在不同地方的发生率也不能说明program的重要性。
C)        说明falls是一个长期的pain，后续医药费用会使人们花更多的钱
D)        Opposite answer，说了新的program的副作用
E)        Opposite，说了program的费用可能会涨得更高

4.        41s
B：The prairie vole, a small North American grassland rodent, breeds year-round, and a group of voles living together consists primarily of an extended family, often including two or more litters.
P：Voles commonly live in large groups from late autumn through winter; from spring through early autumn, however, most voles live in far smaller groups.
C：The seasonal variation in group size can probably be explained by a seasonal variation in mortality among young voles.
推测：voles一般生崽是在秋天到冬天，过了冬天就会有小voles死亡
选项分析：选E
A)        opposite answer，如果春天到早秋young voles多的话，就不会live in small group
B)         提上说的是不同季节vole的数量不同，并不是说year，无关
C)        题上说的size不同是和young voles的死亡率有关，如果因为plants不够，那就不光是young voles死了
D)        同C，温度也会导致adult voles死亡，不光是young
E)        蛇在春天到早秋出没，所以young voles的数量在这个时间段会减少

5.        36s
P：第一代海豚生活的健康长寿，但是他们的后代比没被喂食的海豚的后代寿命短。
P：一个著名的海滩有投喂海豚的program，很多海豚从这里获得每天一半的食物。
推测：被投喂的海豚无法教后代在野外捕食的能力
选项分析：选E
A)        Opposite answer 如果shark很少在open seas，那说明被投喂的海豚不容易死。
B)        把后代生在海滩附近并不说明后代容易死
C)        Opposite answer，投喂的鱼种类一样反而说明被投喂的个野外捕食的没区别
D)        Opposite answer，来的次数少反而说明后代寿命长短和是否被投喂没关系
E)        表明了被投喂的对待后代的关系和野外捕食的的区别

雷东宝

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