关于推理题，真的很不会做，求指点 TPO17

swimswan

先贴两道今天错的题
1.TPO 17 第一篇 最后一段
The astrolabe had long been the primary instrument for navigation, having been introduced in the eleventh century. It operated by measuring the height of the Sun and the fixed stars: by calculating the angles created by these points, it determined the degree of latitude at which one stood (The problem of determining longitude, though, was not solved until the eighteenth century.) By the early thirteenth century. Western Europeans had also developed and put into use the magnetic compass, which helped when clouds obliterated both the Sun and the stars. Also beginning in the thirteenth century, there were new maps refined by precise calculations and the reports of sailors that made it possible to trace one's path with reasonable accuracy. Certain institutional and practical norms had become established as well. A maritime code known as the Consulate of the Sea. which originated in the western Mediterranean region in the fourteenth century, won acceptance by a majority of sea goers as the normative code for maritime conduct; it defined such matters as the authority of a ship's officers, protocols of command, pay structures, the rights of sailors, and the rules of engagement when ships met one another on the sea-lanes. Thus by about 1400 the key elements were in place to enable Europe to begin its seaward adventure.

Why does the author include the information that Western Europeans had “developed and put into use the magnetic compass”?
A.to provide an example of an instrument that was developed after caravels had begun traveling across oceans.
B.To probide an example of an improvement that resulted directly from the invention of the astrolabe
C.To identify one of the technological advances that made see trade with the East possible
D.To explain how the problem of determining longitude was solved


答案是C，我选的是D

看了答案后的想法是：D说的也不错，但是这只是该段中的一个小部分，可以说是局部推理。而从Also后面的内容看出，整段其实是在说C的，因此C应该是整体推理

不知道这个思路对不对，求指点，也请教牛牛思路

2.TPO17 第三篇
◆ At times, it is actually possible to watch the effects of natural selection in host-parasite relationships. For example, Australia during the 1940 s was overrun by hundreds of millions of European rabbits. The rabbits destroyed huge expanses of Australia and threatened the sheep and cattle industries. In 1950, myxoma virus, a parasite that affects rabbits, was deliberately introduced into Australia to control the rabbit population. Spread rapidly by mosquitoes, the virus devastated the rabbit population. The virus was less deadly to the offspring of surviving rabbits, however, and it caused less and less harm over the years. Apparently, genotypes (the genetic make-up of an organism) in the rabbit population were selected that were better able to resist the parasite. Meanwhile, the deadliest strains of the virus perished with their hosts as natural selection favored strains that could infect hosts but not kill them. Thus, natural selection stabilized this host-parasite relationship.

Which of the following can be concluded from the discussion in paragraph 3 about the Australian rabbit population?
A.Human intervention may after the host, the parasite, and the relationship between them.
B.The risks of introducing outside organisms into a biological community are not worth the benefits.
C.Humans should not interfere in host-parasite relationships
D.Organisms that survive a parasitic attact do so in spite of the natural selection process

答案是A，我选的是C

看了答案后的想法是：文中强调了自然选择对这种relationship的重要性，题干问的是Australian rabbit population,而不是对整段的归纳，因此可以通过“自然选择对这种relationship重要”来推出human intervention次要
而C是对整段内容的inference

不知思路正确与否，求指点，也请教牛牛思路

不知道牛牛对于做推断题要没有什么比较有效的方法？求指点，不胜感激

seasunshines

关于第一题  我个人理解如下，如果有异议  欢迎指正
D. To explain how the problem of determining longitude was solved
1 分析该选项,可以先将explain放一下
先看后面的 how the problem of determining longitude was solved
其中关键的结构是was solved
2 再看原文中给出的信息
By the early thirteenth century. Western Europeans had also developed and put into use the magnetic compass, which helped when clouds obliterated both the Sun and the stars.

注意 后面的定语从句 用的动词是helped

我认为有三点要指出来：
a. 选项的solve与文章的help是否互为同义替换
我给出的答案是help 与solve 是不构成同义替换的，
因为文章中给出的是helped when clouds obliterated both the Sun and the stars
很明显这句只是说magnetic compass的作用，
文章的作者在此处并没有表明the problem of determining longitude was solved
更重要的是下面一句话的内容（也就是本段中括号里的一段话）
(The problem of determining longitude, though, was not solved until the eighteenth century.)
这句表明在作者的观点看来，真正 the problem of determining longitude was solved
是的是until the eighteenth century 因为作者使用了solve这个词
所以很明显文章作者的态度是 magnetic compass 只能限于help 而不是help= solve

b 关于By the early thirteenth century和本句中的also 理解
这两个东东都起到了限制作用，但选项中没有注明  
(请结合点a.理解 这里就不赘述 )

c. 关于选项how
我个人认为，要回答How问题的答案应强调的是一个系列的步骤或方式。例如：
  A : how did you escape from the prison?
  B :  I stole the map from the prison officer and then dug a hole in my cell. That's how i escaped form the prison.
由于该句中只是一小点不能完全指明the problem of determining longitude的解决
所以我感觉该选项的how 欠妥；

seasunshines

第二题
关于第二题我想指出的是
1 题目 说的是 from the discussion in paragraph 3 about the Australian rabbit population?
题目说了从第三段就要老实从第三段的整体入手

2 关于你说的 “文中强调了自然选择对这种relationship的重要性”
注意文章最后一句 Thus, natural selection stabilized this host-parasite relationship.
使用的Thus 表明之前的都是  the discussion 并且discuss的结果是论证了 natural selection stabilized this host-parasite relationship 所以整个段落都是在论证这个观点
所以请不要单独认为是在 讨论 Australian rabbit population的例子
用例子的实质是在论述上面的观点

3 关于C 项的说明
C选项中有个很明显的带有主观色彩的结构 should not +动词原形
Gamt 阅读和逻辑中都回避“must/should+ 动词原形”的结构
(除非通过排除法后还剩下两个选项或至少两个选项都有should时可以考虑选用should的选项，这种情况很少见)。
原因：感情色彩这种东西谁说都有理，更何况我们是读者揣摩作者的心思谈何容易，所以不要可轻易下推论，一定要有原文作者的强烈暗示；否则一不小心就会在作者的观点中杂糅了自己的想法。更何况本段只是纯粹的论述，不可能推出带有作者感情色彩的东西。

seasunshines

关于托福阅读中推理题的一些总结
                                                                 seasunshines
1  核心解题方法：排除法
A)对于排除法的运用，必须具备一定的基础
a.对题目询问的考点能够进行准确的把握，即审题要准确
b.能够根据题目的关键位置能够进行准确定位
c.对于各个选项的含义及其侧重点能够准确把握
B)关于排除法的实战运用
a.根据选项的S(主语) V(谓语) O(宾语)进行排除；其中关键的是根据选项的谓语动词进行比较，一定要确定选项的动词是文章中关键动词的同义替换或复述
b.根据选项a.中出现的成分的附加成分进行排除；其中附加成分包括：定语、定语从句、状语、副词、形容词、介词结构等。一定要确认这些附加成份是文章中出现的关键成份或者是文章中某些成份的同义改写、复述。
c.任何推理都要基于作者的明确态度或是相应的语言暗示（托福毕竟是很科学的考试），要排除那些自己强加了的观点、意图或推理以及个人的主观推断。
d. 排除无关的正确推论选项


2解决推理题目的一些"潜规则"
a. 推理题目  “ 一定要避免选内容叙述与文章里使用的字词雷同的选项”
   ----摘录于《托福阅读高分120》 23页第一段 第五行左起
P.S：做了快十五套Tpo这个规则还没失灵过，不过当四个选项运用的复述都不是原文的字词的时候就比较麻烦，此时请参照排除法解题

b. 回避以下选项结构（如果文中没有请不要自行推论）
    比较级 / 最高级 / should或must+ 动词原形 / 无中生有的副词或形容词
可能还有些我记不清了 过几天再翻翻Gmat的总结找一下吧，请见谅~
P.S: 当四个选项都有上述结构或至少两个备选项都有时，此时请参照排除法解题

c.注意文章的逻辑结构的位置（转折、并列、强调等）文章首尾段 段落首尾句
P.S推论题一般要基于段落的基本主题句进行合理推理或与段落的主体大意保持一致；并且推理题有时会在逻辑结构发生转变的地方出推理题，尤其是转折的地方~

d.回避以下太绝对的结构（如果文中没有请不要自行推论）
  every / all /only

e.推理题的正确选项往往具有高度的概括性与归纳性
 

3 常见的阅读中见的比较多的推论：
                           反面（否定、谁的反面）推论、
                           集合范围推论（谁包括谁，谁除了谁会怎么样）、
                           演绎与综合

4 补充：在做推论题的时候，一定要根据原文作者的字词或者作者的强烈暗示进行推论。不要过于盲目或轻率的做出推论，也不要完全放弃那些在文中没出现过的字词所构成的选项(P.S 注意：如果选项中出现了文章没有的概念或是无关概念，建议保守点不要做备选答案;）所以 做推理题是一个遵循原文与适当推理博弈过程，既不能过于保守也不可过于激进。
建议在理解题目后首先从原文已知的概念与题目关键词入手，采用排除法解题，最后做出选择前一定要反问自己它的文中是否有依据以及自己做出推理是否适当。

感觉也就这么多了，如果还有总结日后再发帖吧；一般用排除法能够解决问题的，不会涉及到太多的推论方法，毕竟是阅读不是GMAT逻辑；总之，推理题需要一定的练习，揣摩ETS出题人的思路和想法以及正确选项的用词~

个人攒点RP 顺便总结 一下的东西  以飨各位CD读者  ~
如有异议 欢迎指点 ~