now take longest, on average, to complete work on claims assigned to them. != ability to handle claims promptly is affected as little as possible by the staff cuts,
not equal

In the past, most children who went sledding in the winter snow in Verland used wooden sleds with runners and steering bars. Ten years ago, smooth plastic sleds became popular; they go faster than wooden sleds but are harder to steer and slow. The concern that plastic sleds are more dangerous is clearly borne out by the fact that the number of children injured while sledding was much higher last winter than it was ten years ago.
Which of the following, if true in Verland, most seriously undermines the force of the evidence cited?
Undermine= internal logic
w to p.
p is more dangerous because more number
(Defining goals)
Dangerous is not measure by number of injuried. but possibility of getting injuired.

Metal rings recently excavated from seventh-century settlements in the western part of Mexico were made using the same metallurgical techniques as those used by Ecuadorian artisans before and during that period. These techniques are sufficiently complex to make their independent development in both areas unlikely. Since the people of these two areas were in cultural contact, archaeologists hypothesize that the metallurgical techniques used to make the rings found in Mexico were learned by Mexican artisans from Ecuadorian counterparts.
Which of the following would it be most useful to establish in order to evaluate the archaeologists' hypothesis?
T in A and T in B the same.
B learn from A ( not A to B)

In assessing whether the improvement in advertising sales can properly be attributed to the reorganization, it would be most helpful to find out which of the following?
Following several years of declining advertising sales, the Greenville Times reorganized its advertising sales force. Before reorganization, the sales force was organized geographically, with some sales representatives concentrating on city-center businesses and others concentrating on different outlying regions. The reorganization attempted to increase the sales representatives' knowledge of clients' businesses by having each sales representative deal with only one type of industry or of retailing. After the reorganization, revenue from advertising sales increased.
reorg/ vertical knowledge -----> revenue in ads service

First, understand and learn the various question types. To broadly list the types, they are - Strengthen/Weaken the argument, Evaluate, Inference, Complete the argument, Boldface, find the Assumption, find the flaw, paradox etc. It is very important to understand what the question stem is asking before understanding the argument. (The Manhattan GMAT guide for critical reasoning helped me a lot to improve on this. )
Initially, try to make a quick summary of the argument on paper. Write down only the most important aspects of the argument, using short-hand, signs and variables. Try to identify the premise (facts, supporting statements, information) and the conclusion of the argument. Most of the time the question stem expects you to work on the conclusion of the argument. Track down and attack the conclusion. Start with some pre-thinking before looking at the options, for e.g. What will strengthen the conclusion ? What acts as a bridge between the facts and the conclusion (For assumption questions) ? What could be the reason for such unexpected finding ? During the CR question, remember, that only the information provided by the argument is to be used to work on the argument.
Once you get the general idea about the argument and the question stem, only then start looking at the options (Do not hurry in this process, else you may end up going back and forth between the argument and options). Try to eliminate 2-3 incorrect options. Such options are out-of-scope, irrelevant, going against the question stem or plainly absurd. When left with last 2 options, refer to the conclusion, question stem (from your summary) and take a wise decision. This process can be completed in less than 2 minutes but only with practice. (I got 90% accuracy with this process)
Initially try to master these CR question types, in this order : Strengthen, Weaken, Paradox, Inference, Assumption. These question type will more or less make up for 80% of your CR questions on the test (as per my observation). Do not fret over complicated hard CR questions in the beginning. Start practicing with easy and medium level questions first.
Some quick strategy points :
Strengthen, Weaken and Paradox question options may contain new information, do not eliminate unless you are quite sure.
Assumption options bridge the gap between facts and conclusion of the argument. Negation test : If you negate the correct answer , it will weaken the conclusion completely. This works only on assumption questions
Evaluate : Try to find the answer which has maximum impact on the conclusion i.e. it can both strengthen/weaken the conclusion.
This is just some basic idea to start with CR. I used to dread CR questions but with enough practice, it became my strength in Verbal (Along with SC).

http://m.doczj.com/doc/b5087f39ad51f01dc381f14a.html

　　一、对gmat逻辑推理模式的理解
　　gmat逻辑正确的分类是按照论证形式来分类的，简单来讲就是按照前提和结论的关系来分类的。gmat 逻辑其实考的是评估论证。而在你评估论证之前，是要首先知道这个论证的构建方式的。在非形式逻辑学领域这种种评估论证的方法叫做 Critical Question，简称 CQ。不同的推理模式下CQ的方向和数量完全不同，通过了解不同的推理模式，就掌握了正确答案的方向。
　　二、gmat逻辑的七种推理模式
　　1、类比模式推理。
　　1)特点：
　　两个事情(A,B)的相同点列出来，然后再给出A的一个特点，推理B也应该具有这个特点，B的这个特点就是原文的结论。题目形式如： A和B都有特点 D1，D2，……Dn，可由A有X, 推出B有X。
　　2)评估正确答案的方法：
　　CQ1：相似性问题。A,B这两个案例真的相似吗?若都一样，那么加强推理;若有一个可能的不相似点，那么削弱推理。这种说不相似点的选项最容易被错误的排除掉，容易被当做无关。
　　CQ2：反案例问题。是否存在一个反案例C?若不存在反案例，则加强推理;若存在一个C，使其具有AB的相似点，但是不具有结论中要推断的相似点，则削弱推理。
　　3)解题技巧
　　正确选项中一定涉及了两个案例，或出现和题目中两个案例完全不一样的案例。如果选项只涉及题目中出现的一个案例那么排除。
　　4)注意事项：
　　A在gmat题目中一定不会出现两个选项分别属于两个CQ的方向。因为CQ1和CQ2是同等强度的，无法区分。有大概5%的题目会出现两个选项同属于一个CQ，直接比较强弱。大部分情况下是为了严谨表达，而绝非让你直接比较选项。
　　B类比的核心是就相似点比相似点。不是说题目中凡事出现两个东西的题就是类比题。
　　2、统计枚举推理。
　　1)特点：
　　统计枚举推理前提的范围将在结论种被扩大，由一及百。简单来说就是由样本推总体。用题的形式表示就是：前提——A中有N%是B，则结论——A+C中有N%是B。
　　2)评估正确答案的方法：
　　CQ1：样本是否具有代表性。是否样本具有的性质总体都具有，是否总体具有的性质样本都具有?任何一种否定的情况，就无法将样本的某性质推及总体。
　　CQ2：样本数量是否足够。如果样本没有代表性，数量不够，则不能代表整体。
　　3)解题技巧：正确答案中必须出现样本。然后再判断代表性问题。
　　4)注意事项：
　　A区别于方案模式推理：原文中的方案被论证过(拿几个人做了实验是否能达到方案预想的效果)，就不是方案模式推理。
　　B判断推理模式很重要啊，统计枚举类首要判断标准就是必须出现样本。
　　C逻辑题目中，反驳结论是无法削弱原文的，因为你没有给出任何可信的理由。这也就是为什么我们在因果和果因推理中的CQ都是放在前提，或者是前提和结论的逻辑关系上，不可能只看结论。

　　3、方案目的推理。
　　(1)题型特点：所谓方案推理，其实就是给定目标，为了达成这个目标提出的一种决策。
　　(2)抽象形式：措施/方案-->目的。方案不一定总出现在结论中，很有可能结论是目标，而前提是方案。这种题目不会论证方案哪里好，而是单纯给出一个方案等待评估。
　　(3)解题方法：这种推理模式，必须要说“方案”的内容，或者要侧面反映方案的。在选项中找提及方案的。
　　4、相关因果推理。
　　(1)题型特点：生活中，人们经常把两个同时发生的事情认为是具有因果关系的。
　　(2)抽象形式：Premise：A上升且B上升。Conclusion：A导致B。
　　(3)解题方法：这种推理模式，必须要说“方案”的内容，或者要侧面反映方案的，需要大家在gmat逻辑复习中注意!
　　5、果因推理。
　　(1)题型特点：侦探查案，都是果因模式推理。逻辑上，可以定义为已知现象，回溯原因的推理。几乎所有的现象解释题都是果因推理。(结论是解释。)前提是逻辑上的结果，结论是逻辑上的原因。所以叫果因。
　　(2)抽象形式：Premise：有一个现象/结果。Conclusion: 解释这个现象或者结果。
　　(3)解题方法：这种题要抓住的不是结论，而恰恰是前提。因为前提是“果”。找出现“果”的选项，出现果的一定要解释“果”为什么发生，而不是在说“果”的原理，不是在说“果”是什么。

因果推理。
　　(1)题型特点：这种模式最为简单，也最为容易。原文的前提为因，结论为果。(与果因相反)
　　(2)抽象形式：Premise: 某个事情(原因)。Conclusion：造成某个结果，或者说带来某个现象。
　　(3)解题方法：这种模式需抓住前提。将选项扔到前提和结论之间即可。
　　7、演绎推理。
　　(1)题型特点：这种题目，不是评估类题目。看懂原文就会做。可以根据问题来直接判断种类。
　　(2)问题种类：must be true, main conclusion等。
　　(3)解题方法：
　　must be true: 迷惑性选项有可能为真，但不一定为真;扩大范围;包含新信息;偷换概念等。
　　Main point：迷惑性选项有答案为真，但未包括作者结论，或者答案是原文前提的改写或重复。