12-13
由于昨天CR错得惨不忍睹，而且OG上错题解释已经让我无法自圆其说。我觉得我应该是缺了什么部分的知识。如果不补上，这样做下去只是浪费题目而已。所以我谷歌了下 CR的strategy。
然后找到了这篇。
https://magoosh.com/gmat/2012/save-time-on-gmat-critical-reasoning-questions/
再次强调这种题应该先看问题问什么，然后有针对性地带着问题去看。比如题目要找assumption，那就应该积极找premise是什么，conclusion是什么，然后中间跳过没有提到的就是assumption。说明assumption实际上在premise和conclusion之间起着桥梁的作用。
最简单的题型是这种
Blah blah blah blah blah blah both P and Q. Blah blah blah P more than Q blah blah. Blah blah blah Q instead of P blah blah. Therfore, blah blah T.
Which one of the following is an assumption on which the argument depends?
A. Blah blah blah P or Q blah blah
B. Blah blah blab Q instead of P
C. Blah blah P and Q blah blah T
D. Blah blah blah W and T
E. Blah blah blah without any T
这样的话只要没带结论T的选项直接排除。带了PT或QT的都可以。所以就只剩C。这也确实是我之前做题时的思路。但是难度升阶之后，到处都有T，就出现了我之前的幻觉，觉得每个选项都对。
这个时候要上否定测试法。把选项表述的意思否定之后，看是否会影响结论。如果不影响，那就不是假设。如果影响，那才是假设。
下面这篇文章专门讲怎么快速把assumption找出来。原来是我之前错的题是因为总是找不出来假设。
https://magoosh.com/gmat/2013/assumptions-and-the-negation-test-on-the-gmat/
否定测试，就是假定否定成立的话，看影不影响结论。如果不影响，那么就不是假设。如果影响，那就是假设。
而且假设实际上可以有多种。
（再次吹爆国外的content mkt的功底，不仅边讲解清楚策略，以及放了配套练习，可以马上实测一下自己有没有理解文章里的策略。那个练习还是想实际考试一样的操作界面，右上角有时间提示，这个答题交互细节可以说走心了）
文章里举了个例子。
The Spotted Mole is a rodent that burrows underground and eats all forms of vegetable matter. Farmers are concerned that this mole could eat some of their commercial fruits, planted in above-ground planters and bins. The farmers need not worry about the Mole, though, because throughout the region in which the Spotted Mole is found, birds of prey such as hawks and falcons are active, and these birds would prey upon the Spotted Mole if the mole came above ground at all. Therefore, the Spotted Mole poses no threat to these totally above-ground fruits.
Which one of the following is an assumption on which the argument depends?
(A) The birds of prey capture and kill every single Spotted Mole that comes above ground.
(B) Some land-based mammals active in this region, such as fox, will also hunt and eat the Spotted Mole on a regular basis.
(C) No other animal could pose as significant a threat to the above-ground fruits as could the Spotted Mole.
(D) The times of day the Spotted Mole feeds are the same as the times of day that the birds of prey are in the air.
(E) Larger burrowing mammals, such as badgers or weasels, can dig up the burrows of the Spotted Mole, endangering those that remain underground.
结论是不用XX鼠患（大概没查字典）担心，因为地面上有天敌盯着。
我当时上来就选了A。然后错得很惨烈。实际上不用那么惨烈绝对，农民baibai也是可以不用担心的。而应该是捕食关系的二者活动时间要一样，如果这个不成立的话，结论就是错的，农民baibai不能指望天敌了。
果然用了这个方法之后，很多选项就能很快排除了。包括昨天做的错题。不能用新税那题用这种方法看就瞬间通透了。（但除了641，还是没绕过弯来……
除了assumption类型的题还有另外7种。削弱/加强结论，可推出的结论/inference，明确argument的结构，找矛盾点，补充argument，评价argument的质量。前4种占到了75%的比例。前三种题型都可以通过找到assumption的方法解决。
今天只刷了25道。（AWA一直来不及写嘤嘤
686
Economist: The price of tap water in our region should be raised drastically. Supplies in local freshwater reservoirs have been declining for years because water is being used faster than it can be replenished. Since the price of tap water has been low, few users have bothered to adopt even easy conservation measures.
The sections in boldface play which of the following roles in the economist's argument?
B) The first is an observation for which the second provides an explanation; the second is the main conclusion but not the only conclusion.
C) The first is a premise supporting the argument's main conclusion; so is the second.
这个就属于前面提到的第五种类型的题目，判断argument的结构。第一句实际上就去吃呼吁大家行动：水价应该提高。原因是供量下降严重，因为V用>V产，V用大又因为价格低，大家都不省着点用。这个链条就感觉是供量下降是第一层原因，然后水价低是更深层的原因。
这个最后归因于水价低，所以提高水价，我本来理解为这两个都算是结论。只是呼吁行动是总结论，本质原因水价低算是初步结论支持最后结论的。
但OG上解释说这水价低，也只能算成argument里的premise，而且是基于观察的premise，或者说causal claims。
694
City council member: Demand for electricity has been increasing by 1.5 percent a year, and there simply is no more space to build additional power plants to meet future demand increases. We must, therefore, begin to curtail usage, which is why I propose passing ordinances requiring energy-conservation measures in all city departments.
The city council member's proposal assumes which of the following?
E) The city department that successfully conserve energy will set a good example for residential and industrial consumers of electricity.
A) Existing power plants do not have the capacity to handle all of the projected increase in demand for electricity.
这个就是典型的找assumption的题。结论是shi政单位省电，premise是用电需求上升，没地建电厂，只能想法省电。（艹脑子打结了
这里的leap是，要想证明这个结论是对的，那么作者默认的成立的假设是，不省电就以后不够电用，也就是没有别的办法再供更多的电了。所以是默认现有电厂无法满足未来的需要。
但我还是忍不住翻了attack了premise，如果单位们不起好头，那么就达不到最终省电的目的。但是这个已经和结论无关了？啊啊啊，为什么这题和641一样把我脑子带沟里去了。我还是要再找找assumption其他的strategy，感觉还是有个知识gap没有补上。
704
For the period from the eighth century through the eleventh century, the shifting boundaries between Kingdom F and Kingdom G have not been well charted. Although a certain village in a border region between the two kingdoms usually belonged to Kingdom G, ninth-century artifacts found in the village were in the typical Kingdom F style of that time. It is unclear whether the village was actually a part of Kingdom F in the ninth century or whether it was a part of Kingdom G but had merely adopted Kingdom F's artistic styles under Kingdom F's cultural influence.
Which of the following would, if found in ninth-century sites in the village, best help in determining whether the village was a part of Kingdom F or Kingdom G in the ninth century?
C) Knives and other utensils made from metal typical of ninth-century mining sites in Kingdom F.
E) Numerous teeth from the ninth century with a chemical signature typical only of teeth from people who had grown up in the heart of Kingdom F.
8世纪到11世纪期间，某个在国界上的村子可能在9世纪的时候属于F国，因为出现了9世纪的F过特色艺术作品。哪个证据可以证明村子就是属于F国的？
不成立的话，结论就错的。OG这里体现为原来F国市中心的人口的牙齿可以证明这一点。
706
Infotek, a computer manufacturer in Katrovia, has just introduced a new personal computer model that sells for significantly less than any other model. Market research shows, however, that very few Katrovian households without personal computers would buy a computer, regardless of its price. Therefore, introducing the new model is unlikely to increase the number of computers in Katrovian homes.
Which of the following is an assumption on which the argument depends?
E) Most personal computers purchased in Katrovia are intended for home use.
C) Katrovians in households that already have computers are unlikely to purchase the new Infotek model as an additional computer for home use.
结论：新个人电脑不会增加某国的家庭电脑数量。premise：没有个人电脑的家庭不会买电脑，不管有多便宜。而且这个新的电脑卖得比其他model便宜。
如果不是家用，那结论会被削弱。但这种和assumption又什么区别？
709
Transportation expenses accounted for a large portion of the total dollar amount spent on trips for pleasure by residents of the United States in 1997, and about half of the total dollar amount spent on transportation was for airfare. However, the large majority of United States residents who took trips for pleasure in 1997 did not travel by airplane but used other means of transportation.
If the statements above are true, which of the following must also be true about United States residents who took trips for pleasure in 1997?
C) Per mile traveled, those who traveled by airplane tended to spend more on transportation to their destination than did those who used other means of transportation.
A) Achieving political compromises is not all that is necessary for the proper functioning of a government.
交通费用占到了大家出去玩的很大比例。交通费里有一半都是坐飞机。但是大部分人都选择不坐飞机出去玩。
这说明不坐飞机的大家出去玩花的比坐飞机的要少。
CR给人的挫败感比SC RC都更大，是属于看完OG开完网上的建议都没理清楚为什么对，为什么错的难。枯……
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