今天先为大家整理OG12的前5道例题及其讲解，附带解析和难度等级分析，大家如果还没有练习OG可以先参考一下OG的难度。
OG12-CR-1.(削弱题型)
"Life expectancy" is the average age at death of the entire live-born population. In the middle of the nineteenth century, life expectancy in North America was 40 years, whereas now it is nearly 80 years. Thus, in those days, people must have been considered old at an age that we now consider the prime of life.
Which of the following, if true, undermines the argument above?
(A)In the middle of the nineteenth century, the population of North America was significantly smaller than it is today.
(B)Most of the gains in life expectancy in the last 150 years have come from reductions in the number of infants who die in their first year of life.
(C)Many of the people who live to an advanced age today do so only because of medical technology that was unknown in the nineteenth century.
(D)The proportion of people who die in their seventies is significantly smaller today than is the proportion of people who die in their eighties.
(E)More people in the middle of the nineteenth century engaged regularly in vigorous physical activity than do so today.
OG解释：
Argument Evaluation
Situation
Life expectancy in mid-nineteenth century North America was 40 years; now it is almost 80. What we think of as the prime of life must have been considered old in that earlier era.
Reasoning
what point weakens this argument? The argument is discussing life expectancy over the entire population of those born alive. The argument relies on the idea that if 40 years was
the average life expectancy, then the usual length of life must have been around 40. But averages can be misleading. What if, in the nineteenth century, the number of infants born alive but not surviving their first year was far higher than it is today? If this were so, it would significantly reduce the average age at time of death of the population as a whole—but of course that population could have contained many who lived well into their seventies or eighties. Thus, if we add the information that first-year infant mortality was quite high 150 years ago, the conclusion those 40 years was considered old then would be much less well supported.
A. The size of the population is irrelevant to the argument.
B. Correct. Greatly reducing first-year infant mortality will have a large impact on the average life expectancy of the population as a whole. That,rather than grown adults living twice as long, is enough to account for a large portion of the doubling in average life expectancy.
C. This point supports rather than weakens the argument.
D. This point supports the argument.
The correct answer is C.
版主点评：人均预期寿命是算出来的，出生婴儿的死亡率降低，会直接拉高预期寿命。
因此此题属于典型的他因削弱+数学。
掌握要点：遇到数量变化，多从分子、分母是否有变化角度考虑。
难度级别：★☆☆☆☆
OG12-CR-2.(评价题型)新题
Scientists propose placing seismic stations on the floor of the Pacific Ocean to warn threatened coastal communities on the northwestern coast of the United States of approaching tidal waves caused by earthquakes. Since forewarned communities could take steps to evacuate, many of the injuries and deaths that would otherwise occur could be avoided if the government would implement this proposal.
The answer to which of the following questions would be most important in determining whether implementing the proposal would be likely to achieve the desired result?
(A)When was the last time that the coastal communities were threatened by an approaching tidal wave?
(B)How far below sea level would the stations be located?
(C)Would there be enough time after receiving warning of an approaching tidal wave for communities to
evacuate safely?
(D)How soon after a tidal wave hits land is it safe for evacuees to return to their communities?
(E)Can the stations be equipped to collect and relay information about phenomena other than tidal waves
caused by earthquakes?
OG解释：
Evaluation of a Plan
Situation
Scientists plan to place on the floor of the Pacific Ocean seismic stations that can sense earthquakes and warn threatened coastal communities when they will be threatened by tidal waves. Communities that receive warning that tidal waves are approaching could evacuate, and injuries and deaths that the tidal wave would most likely cause could be avoided, under this plan.
Reasoning
What would it be most important to know in determining whether implementing the plan will achieve its desired result, preventing injuries and deaths? Communities must actually evacuate for the plan to achieve the desired result, and that evacuation must be accomplished without itself causing injuries or deaths. For this to happen, the proposed seismic stations' warnings must come early enough to enable the communities to perform a safe evacuation.
A. Knowing the last time that coastal communities were threatened by an approaching tidal wave
might be useful in determining whether the seismic stations are a good use of resources (because
it might indicate how often tidal waves pose a threat), but it does not help determine whether the
stations' warnings would lead to evacuations preventing injuries and deaths when a tidal wave
does hit.
B. The plan is to install the seismic stations on the floor of the Pacific Ocean. Knowing the floor's
depth would not help determine whether the seismic stations would help prevent injuries and
deaths when a tidal wave hits.
C. Correct. If the answer to this question is yes, it will indicate that the plan is more likely to
achieve its desired result. If the answer is no, it will show that the plan will not do so.
D. Knowing when evacuees could safely return to their communities is irrelevant to the desired
result of the plan as described in the passage.
E. While it might be useful to know whether the seismic stations could be used to gather data on
phenomena other than tidal waves, this does not speak to the issue of whether the stations would
help prevent injuries and deaths caused by tidal waves.
The correct answer is C.
版主点评：本题题干中信息简化之后就是这样的：
如果装了可以发地震预警的观测站，那么当地居民就能及时撤走，因此可以避免许多伤亡。
问题是，以下哪一个问题的答案对于judge题干中所描述的措施是否有效是有意义的。
浏览以下选项之后便会发觉A.B.D.E其实都是无关选项，因此排除，而C选项中受到预警之后是否有时间撤走确实是决定该项措施是否有效的决定因素。所以选C。
难度级别：★★☆☆☆
OG12-CR-3.(削弱题型)
Homeowners aged 40 to 50 are more likely to purchase ice cream and are more likely to purchase it in larger amounts than are members of any other demographic group. The popular belief that teenagers eat more ice cream than adults must, therefore, be false.
The argument is flawed primarily because the author?
(A).fails to distinguish between purchasing and consuming
(B).does not supply information about homeowners in age groups other than 40 to 50
(C).depends on popular belief rather than on documented research findings
(D).does not specify the precise amount of ice cream purchased by any demographic group
(E).discusses ice cream rather than more nutritious and healthful foods
OG解释：
Argument Evaluation
Situation
Adults aged 40 to SO buy more ice cream than does any other demographic group (for example, teenagers). Does this mean that adults consume more ice cream than teenagers do?
Reasoning
A flawed assumption underlies the reasoning: the assumption that the buyers of the ice cream are also the eaters of the ice cream. Although the demographic group homeowners aged 40 to 50
purchases more ice cream than does any other demographic group, it is quite likely that much of the ice cream purchased by those homeowners is for consumption by family members rather than for exclusive consumption by the purchaser. This leaves open the possibility that teenagers may indeed be the largest consumers of ice cream.
A. Correct. The failure to make this distinction led to the making of the flawed assumption.
B. This is false: The argument tells us (indirectly) that homeowners aged 40 to 50 buy more ice cream than does any other group—which allows us to infer that they buy more than do homeowners aged 30 to 40, for example. But even if the argument had stated such information explicitly, it would not have offered any better support for its conclusion.
C. There is nothing in the argument to suggest that the information given is based on popular belief.
D. Providing precise information about the quantity of ice cream purchased by homeowners aged 40 to 50 would not improve the argument at all.
E. The subject is ice cream, not nutrition, so this point is irrelevant.
The correct answer is A
版主点评：可怜天下父母心。父母买得多，吃得却少。答案说的就是这个意思。
把握要点：好好努力，孝敬父母。
难度级别：☆☆☆☆☆(这种难度的题目在考试中几乎不会出现，因为easy级别太高)
OG12-CR-4.(Flaw题型)新题
According to a prediction of the not-so-distant future published in 1940, electricity would revolutionize
agriculture. Electrodes would be inserted into the soil, and the current between them would kill bugs and weeds and make crop plants stronger.
Which of the following, if true, most strongly indicates that the logic of the prediction above is flawed?
(A) In order for farmers to avoid electric shock while working in the fields, the current could be turned off at such times without diminishing the intended effects.
(B) If the proposed plan for using electricity were put into practice, farmers would save on chemicals now
being added to the soil.
(C) It cannot be taken for granted that the use of electricity is always beneficial.
(D) Since weeds are plants, electricity would affect weeds in the same way as it would affect crop plants.
(E) Because a planting machine would need to avoid coming into contact with the electrodes, new parts for planting machines would need to be designed.
OG解释：
Evaluation of a Plan
Situation
In 1940, electricity was predicted to revolutionize agriculture. This prediction suggested that electric current running between electrodes inserted into the soil would kill bugs and weeds while encouraging the growth of crop plants.
Reasoning
Which point most suggests that the logic used in formulating the prediction is fl awed? Electricity will revolutionize agriculture, it is said, because current can be run through electrodes placed in the soil. This current will kill bugs and weeds while strengthening plants. But how will the current accomplish this feat? More specifically, how will it kill one kind of plant (weeds) while strengthening another (crop plants)?
A. The logic of the prediction has nothing to do with whether the current can be turned on and off; rather, it is concerned with the current itself and its effects.
B. Rather than suggesting that the logic of the prediction is fl awed, this serves to support the prediction: Farmers’ saving on chemicals would be part of the predicted agricultural revolution.
C. The argument does not take for granted that the use of electricity is always beneficial; it merely suggests that it would be of great benefit to agriculture.
D. Correct. This statement properly identifies a problem with the prediction: It provides no reason to believe that the electricity would affect crop plants and weeds differently.
E Rather than suggesting that the logic of the prediction is fl awed, this serves to support the prediction: Changes in planting machines would be part of the predicted agricultural revolution.
The correct answer is D.
版主点评:我们看这道题的逻辑，提干中给出了这样一个逻辑：
电流可以杀死小虫子和杂草——庄稼可以长得更好——电力的应用会给农业带来革命性的影响。
要使得这一逻辑成立，必须能够让下面的两个逻辑链条成立。
第一个链条就是电流杀死小虫子和杂草能够使得庄稼长得更好;
第二个链条是庄稼长得更好可以证明电力应用给农业带来革命性的影响。
D选项说，杂草也是作物的一种，电流既然可以杀死杂草，也可能会杀死庄稼。
这样就破坏了第一个逻辑链条，削弱了提干的逻辑。
当然，削弱提干逻辑的可能还有许多，比如说电流杀死了小虫子，
但有些小虫子对于庄稼生长有益，这样也削弱了第一个逻辑链条。
同样，如果用电流杀虫的成本高过农药，那么从成本角度电力也无法应用到农业中，
从而削弱了第二个逻辑链条。
所以，面对逻辑题目的时候，大家可以思考一下提干的逻辑由哪几个链条组成，这样会对于解题很有帮助。
难度级别：★★★★☆
OG12-CR-5.(评价题型)
A company is considering changing its policy concerning daily working hours. Currently, this company requires all employees to arrive at work at 8 a.m. The proposed policy would permit each employee to decide when to arrive—from as early as 6 a.m. to as late as 11 a.m.
The adoption of this policy would be most likely to decrease employees’ productivity if the employees’ job functions required them to?
(A) work without interruption from other employees
(B) consult at least once a day with employees from other companies
(C) submit their work for a supervisor’s eventual approval
(D) interact frequently with each other throughout the entire workday
(E) undertake projects that take several days to complete
OG解释：
Evaluation of a Plan
Situation
A company considers changing all employees' starting time from 8 a.m. to individually
flexible arrival hours, anytime from 6 to 11 a.m.
Reasoning
Under what conditions could this plan cause employees' productivity to decline? Consider the
job functions defined in the answer choices and determine which entails requirements
that would most likely be in conflict with the proposed plan. A plan that allows a five-
hour range of start times would make it far more difficult for employees to coordinate
their schedules. This would make it difficult, if not impossible, for employees to
collaborate with each other throughout the workday and could well decrease productivity
A. Working without interruption would likely mean improved productivity.
B. Assuming that all employees are in the same time zone (we are not told otherwise), the flexible hours would still leave plenty of time for at least one daily consultation during the regular business hours of the workday.
C. Eventual approval indicates that the flexibility exists to permit employees’ submissions at any time.
D. Correct. The wide range of flexibility in regards to working hours would make frequent interaction difficult, if not impossible, and would be likely to decrease employees’ productivity.
E. We are not told that the projects involve significant interaction; so such projects would be accomplished just as easily on the proposed flexible schedule.
The correct answer is D.
版主点评: 公司提出员工自己可以决定上班时间。
基本意思是问如果下面那个是真的，这个方案可能会降低效率。
通读一遍答案就可以很容易的筛选出答案D。
因为如果工作要求所有的员工要协同合作，互相沟通。
难度级别：★☆☆☆☆
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