备考记录—持续更新

Doris707

544. Neuroscientist: Memory evolved to help animals react appropriately to situations they encounter by drawing on the past experience of similar situations. But this does not require that animals perfectly recall every detail of all their experiences. Instead, to function well, memory should generalize from past experiences that are similar to the current one.
The neuroscientist’s statements, if true, most strongly support which of the following conclusions?
A. At least some animals perfectly recall every detail of at least some past experiences.
B. Perfectly recalling every detail of all their past experiences could help at least some animals react more appropriately than they otherwise would to new situations they encounter.
C. Generalizing from past experiences requires clear memories of most if not all the details of those experiences.
D. Recalling every detail of all past experiences would be incompatible with any ability to generalize from those experiences.
E. Animals can often react more appropriately than they otherwise would to situations they encounter if they draw on generalizations from past experiences of similar situations.
这题是归纳推理，直接去原文找逻辑关系，然后看选项中的逻辑关系是否与原文中的一致，多数情况下选项都是充分必要条件颠倒，或者是原推理关系的非等价变换，或者是原文中根本么有涉及的范围。把这些错误选项都排除，剩下的那个就是正确选项。


545. Astronomer: Most stars are born in groups of thousands, each star in a group forming from the same parent cloud of gas. Each cloud has a unique, homogeneous chemical composition. Therefore, whenever two stars have the same chemical composition as each other, they must have originated from the same cloud of gas.
Which of the following, if true, would most strengthen the astronomer’s argument?
A. In some groups of stars, not every star originated from the same parent cloud of gas.
B. Clouds of gas of similar or identical chemical composition may be remote from each other.
C. Whenever a star forms, it inherits the chemical composition of its parent cloud of gas.
D. Many stars in vastly different parts of the universe are quite similar in their chemical compositions.
E. Astronomers can at least sometimes precisely determine whether a star has the same chemical composition as its parent cloud of gas.
P：stars in the same group have the same c.c.
C: stars have the same c.c. are from the same group
前提和结论充分必要条件颠倒，asp是只有have the same c.c.这一个必要条件就可以推出from the same group，不再有其他必要条件
如果文段是充分必要条件颠倒，那么ASP就是必要条件仅有这一个，不再有其他

Doris707

V-ing 放在句首和句末1、放在句首，修饰紧随其后的主句subject，或者修饰紧随其后的主句的谓语中心
2、放在句末，修饰紧随其前的主句的谓语中心

Doris707

Main bias：
Look-ahead bias（模拟未来结果作为分析基础）
Bias created by the use of information or data in a study or simulation that would not have been known or available during the period being analyzed. This will usually lead to inaccurate results in the study or simulation.


e.g.
In Kravonia, the average salary for jobs requiring a college degree has always been higher than theaverage salary for jobs that do not require a degree.  Current enrollments in Kravonia's colleges indicate that over the next four years the percentage of the Kravonian work force with college degrees will increase dramatically. Therefore, the average salary for all workers in Kravonia is likely to increase over the next four years.

In Kravonia, the average salary for jobs requiring a college degree has alwaysbeen higher than the average salary for jobs that do not require a degree.  Over the last few years, the number of Kravonians enrolled in college has been growing steadily.  Therefore, the number of Kravonians entering the job market who have at least the qualification of a college degree will eventually be significantly higher than it has been over the last few years.

前提中在讨论enrollment的情况，结论中讨论work force entering the job market的情况，Asp：the numbers of enrollments = the numbers of work force
weaken: point out the Asp; claim that Asp is wrong (after graduate from college, many people will apply postgraduate program)

Doris707

babybearmm的SC经验谈
https://forum.chasedream.com/thread-739174-11-1.html

active voice来强调动作和动作发出者之间的联系。而passive voice强调的是动作和动作受体之间的联系。
主动与被动的本质区别在于：是否需要人为参与
如：prove、be proved to be
derive from: 一个物种从另一个物种来，自主进化来的，不需要人参与
be derived from：糖是从甘蔗中提炼出来的，需要人参与，人不参与糖不会自己进去榨糖机
主动或者被动产生歧义有时候是来源于介词：如by、to
一个句子，用active voice，表达的信息量是什么？强调的信息量又是什么？换成passive voice又是怎么样的？通常哪一种voice所表达的信息量更大呢？你能找几个用passive voice更好的句子，来justify the usage of passive voice么？（提示：尝试在OG SC文档中搜索passive voice或者active voice）
这有一道prep的题目
http://www.manhattangmat.com/forums/before-scientists-learned-how-to-make-a-synthetic-growth-t637.html?sid=b2063f3acc7bbe9dbdb17b3243fa3460

Before scientists learned how to make asynthetic growth hormone, removing it painstakingly in small amounts from the pituitary glands of human cadevers.

A)
B) scientists had learned about makinga synthetic growth hormone, they had to remove it painstakingly
C) scientists learned how to synthesize the growth hormone, it had to be painstakingly removed
D) learning how to make a synthetic growth hormone, scientists had to remove it painstakingly
E) learning how to synthesize the growth hormone, it had to be painstakingly removed by scientists


**adj n vs n to be adj
形容词描述的是名词的内在属性，不定式描述的是被赋予的属性。

Doris707

RC strategies：
https://gmatclub.com/forum/gmat-club-s-reading-comprehension-strategy-guide-83101.html#p622849

Doris707

Spend at least five minutes at a time imagining different details about taking the test. Visualize yourself spotting sentence structures based on keywords or commas. Visualize yourself checking for X & Y consistency for SC questions or recognizing a Data Sufficiency Percent vs. Actual Number question. You know what to look for and where the pitfalls are (multiple % data points without any actual number data points are useless if they ask you a “how many” question).
Your visualization scene doesn’t need to be the same each time, but you need to tap into a sense of accomplishment, calm, and confidence. Do this every morning and before bedtime.
Neurophysiologist researchers at Stanford University (my alma mater) and University of Chicago evaluated the efficacy of visualization. They compared two sets of basketball players. The first group practiced playing whereas the second group only imagined practicing. The players who didn’t physically practice, but visualized peak performance, improved 23 -30 percent in their actual basket-shooting ability, whereas the students who physically “practiced” saw little improvement. (source)
source: http://www.gmatpill.com/

看到这里深有感触，从今天起实施。其实这方法，大学上跳水课的时候，我们的老师——著名教练于芬，就跟我们教过，她管这叫“意象训练”，就是在脑子里想一整套完美的跳水动作。当时我觉得很神奇，现在看到了科研证据，感叹methodology真是一门学问啊。关键是要把知识转化为行动力，为啥我之前就没这么去做呢？

-- by 会员 babybearmm (2012/2/26 11:25:38)

看babebearmm前辈的帖子，看到非常有用的赶紧mark下来

Doris707

Untilnow, only injectable vaccines against influenza have been available.  Parents are reluctant to subject children tothe pain of injections, but adults, who are at risk of serious complicationsfrom influenza, are commonly vaccinated. A new influenza vaccine, administered painlessly in a nasal spray, iseffective for children.  However, sincechildren seldom develop serious complications from influenza, no significantpublic health benefit would result from widespread vaccination of childrenusing the nasal spray.

Whichof the following is an assumption on which the argument depends?

A.Any person who has received the injectable vaccine can safely receive thenasal-spray vaccine as well.

B.The new vaccine uses the same mechanism to ward off influenza as injectablevaccines do.

C.The injectable vaccine is affordable for all adults.

D.Adults do not contract influenza primarily from children who have influenza.

E.The nasal spray vaccine is not effective when administered to adults.

题目中说adults are at risk of serious complications from fluenza, however, children seldom develop serious complication from fluenza, so public ......

[size=13.3333px]以偏概全：children = public

[size=13.3333px]用数学集合的概念来看：前提在说子集的事情，但是推导出的结论确实全集的事情。

[size=13.3333px]Asp：全集=子集

[size=13.3333px]改错：children + adults = public

Doris707

Sample-selecting bias - survivor bias

Ihave visited hotels throughout the country and have noticed that in those builtbefore 1930 the quality of the original carpentry work is generally superior tothat in hotels built afterward. Clearly carpenters working on hotels before1930 typically worked with more skill, care, and effort than carpenters whohave worked on hotels built subsequently.

Whichof the following, if true, most seriously weakens the guidebook writer'sargument?

(A)The quality of original carpentry in hotels is generally far superior to thequality of original carpentry in other structures, such as houses and stores.

(B) Hotelsbuilt since 1930 can generally accommodate more guests than those built before1930.

(C) Thematerials available to carpenters working before 1930 were not significantlydifferent in quality from the materials available to carpenters working after1930.

(D) Thebetter the quality of original carpentry in a building, the less likely thatbuilding is to fall into disuse and be demolished.

(E) Theaverage length of apprenticeship for carpenters has declined significantlysince 1930.

P：1930年前的H比1930年之后的H质量好

C：1930年前的人技术比较好

C选项：材料没有差别——加强。如果说材料没有差别，那么造成H质量有差别的原因就更有可能是技术。消除了一个weaken，就相当于是加强了

Doris707

Causality
Every fall Croton's jays migrate south.  The jays always join flocks of migrating crookbeaks with which they share the same summer and winter territories.  If a jay becomes separated from the crookbeaks it is accompanying, it wanders until it comes across another flock of crookbeaks.  Clearly, therefore, Croton's jays lack the navigational ability to find their way south on their own.

Which of the following, if true, most strengthens the argument above?

A. Croton's jays lay their eggs in the nests of crookbeaks, which breed upon completing their southern migration.
B. The three species most closely related to crookbeaks do not migrate at all.
C. In the spring, Croton's jays migrate north in the company of Tattersall warblers.
D. Species other than Croton's jays occasionally accompany flocks of migrating crookbeaks.
E. In the spring, crookbeaks migrate north before Croton's jays do.
P：J migrate with C and wait C
C: J lack the nvg
Asp: no other reasons make J need company
正确答案：加强——换一个时间，这种现象依然存在

Doris707

注意前提和结论讨论的不是同一个量：总产量 = 人均产量 * 人数

Inresponse to mounting public concern, an airplane manufacturer implemented aprogram with the well-publicized goal of reducing by half the total yearlyamount of hazardous waste generated by its passenger-jet division.  When the program began in 1994, thedivision's hazardous waste output was 90 pounds per production worker; lastyear it was 40 pounds per production worker. Clearly, therefore, charges that the manufacturer's program has not metits goal are false.  

Whichof the following is an assumption on which the argument depends?

A.The amount of nonhazardous waste generated each year by the passenger-jetdivision has not increased significantly since 1994.

B.At least as many passenger jets were produced by the division last year as hadbeen produced in 1994.

C.Since 1994, other divisions in the company have achieved reductions inhazardous waste output that are at least equal to that achieved in thepassenger-jet division.

D.The average number of weekly hours per production worker in the passenger-jetdivision was not significantly greater last year than it was in 1994.

E.The number of production workers assigned to the passenger-jet division was notsignificantly less in 1994 than it was last year.

目标是减少总产量，方案减少了人均产量→不代表总产量减少了

Asp：人数没有变化