"using", like "including", doesn't follow the normal rules for "__ing" modifiers.

when "using" is used in this kind of context (to describe the tools with which something is accomplished), its behavior is essentially identical to that of "with".
thus, you can think of this "using" as a preposition, like "with".

the problem with (c) is NOT grammatical; the grammar of (c) is just fine.
the problem with (c) is that it uses two different transitions incorrectly.

* if you say "subject + clause + BY VERBing", then "by VERBing" must explain HOW the main clause occurred.
e.g.
i prepared for the test by reviewing takeaways on the MGMAT forums.
note that the boldface clause describes HOW i prepared for the test.

choice (c) means that using websites, etc. was how the industry organized the campaign -- in other words, they used the websites and public meetings to organize the campaign in the first place. that's an incorrect meaning.
(the campaign ITSELF used these things; the correct modifier in (a) and (b) shows that relationship.)

* if you say "subject + clause + IN VERBing", then subject + clause must be an ACTUAL PART of the action of VERBing.
e.g.
i solved all the problems in OG12 in preparing for the GMAT.
--> notice that solving the problems IS ACTUALLY PART OF preparing for the test.

choice (c) fails here, too, since organizing the campaign (the main clause) is not ACTUALLY PART OF convincing the government.


choice (e) has two problems.

the first is "in convincing", which is wrong for the same reason why it's wrong in choice (c). see above.

the other is incorrect verb tense. "which used" (simple past tense) shouldn't be in a tense occurring prior to "has organized" (present perfect). this construction mistakenly suggests that the campaign "used X, Y, and Z" before it was even organized in the first place.

an "appositive" vs an "absolute phrase"

you should mostly use MEANING to differentiate between the two.
for instance:
the singer sang the song with intense emotion, her voice moving the audience to tears --> absolute phrase
this is the official guide, a book containing over 800 problems --> appositive

if you think in terms of meaning, it's a rather large difference: the absolute phrase modifies the ACTION of the preceding clause, while the appositive gives more information about a THING/ENTITY/CONCEPT.

it's so important to ascertain the meaning of the sentence FIRST, before you dive into analyzing possible errors.

the same thing is true for many other types of modifiers, such as prepositional phrases, as well.

e.g.
I read the book on the train --> this prepositional phrase modifies the ACTION "read the book".
I read the book on the table --> this prepositional phrase modifies the NOUN "book".
grammar won't help you figure this out -- you have to ascertain the meaning of the sentence using the same sort of common sense that allows you to have everyday conversations with people who don't speak using perfect grammar (i.e., everyone you will ever talk to).

modifier issues aren't really grammar issues -- they're meaning issues.
i.e., modifiers are not normally wrong because they are grammatically incorrect; they are normally wrong because they modify things that don't make sense. therefore, in most modifier errors, there is no such thing as a "proper grammar explanation" because grammar isn't even the issue in the first place.

in the construction "it is (adjective) for XXXX to (verb)", the adjective describes what XXXX experience(s) in trying to (verb).

e.g.,
This book is hard for me to read.
(I experience difficulty in reading this book.)

It is difficult for Liz to talk to her ex-husband.
(liz has trouble talking to her ex. we don't know whether the converse is true.)

so, choice E is saying that the appliances themselves have to spend a lot of money "to be bought on credit". well, that doesn't make any sense.

also，even if your knowledge of these constructions is nil, you should still be able to kill E because it's so terribly wordy and clunky, as compared to the other choices.
(no, wordiness is not an actual error... but the correct answers are NEVER more wordy / less efficient than the incorrect answers. thus, you can still use differences in wordiness as viable criteria for elimination.)

"so that" is not a modifier; it connects two independent sentences. so, the problem with using "the" here is that "the" would have to make sense BY ITSELF.

consider the following:
I have the box that you bought yesterday.
I have the box in which the sewing scissors are stored.
vs.
I bought a box, so that you can store your sewing scissors.
--> we CAN'T write "the" here, because "the box" doesn't make any sense by itself.

for the same reason, the choices with "the kind..." and "so that" don't work, either.

“Political situations have caused an increase in gas prices ” correct
“Political situations have caused increasing gas prices ” incorrect

You can't memorize this kind of thing as a structure, because structure isn't the issue. The issue is what the sentence means.

In the pair above, the incorrect example is wrong because political situations don't "cause gas prices"; that's nonsense. (Gas prices are not an event precipitated by political events.) In this instance, "increasing" is an adjective.

In the current sentence, the meaning is altogether different.
We're talking about the action of "buying on credit".

In addition, "buying" is the best noun available, because there's no dedicated noun form available (e.g., there's no such thing as, say, "buyage"). By contrast, the noun "increase" is available.

You can use "it is (adjective) for XXXX to (verb)" construction without a subject, but only if the statement is universally true -- i.e., for everyone who might find him-/herself in the situation.
E.g., when interest rates go up, it becomes more expensive for absolutely anyone to buy on credit, because ... well, because interest rates went up.

In a sentence describing a consequence that's particular to a certain person/group, you have to say who that is. Here, you're talking about consequences that pertain to a certain executive, so the sentence must be specific.

If the "to ___" phrase is long enough, this construction will become preferable.
For instance, in this sentence, change "buy(ing) on credit" to "buy(ing) expensive items on credit or borrow(ing) substantial sums of money".
With a phrase that long, choice B, while still technically correct, will become completely unreadable. With its agreement problem fixed, choice C will still work well.

either "by imitating and practicing" or "by imitation and practice" is acceptable, here. once you've established parallelism, the point is to move on to other criteria.

"from each one to others", "from one to another" and "to others"
this is a distraction.
if you see random changes in word choice -- and you can't decide them /1/ logically or /2/ by referring to something else in the sentence -- then those choices are there just to distract you. ignore them and find something else.

the sentence is written very specifically to emphasize the curiosity per se.
ironically, the sentence is written expressly to MINIMIZE the importance given to the chimpanzees themselves!

if the point was to emphasize the involvement of the chimps, then the sentence would be written with the chimps as the subject. this would be quite easy to do: ...they transmit patterns of behavior by imitating them...

instead the author has taken a sentence whose earlier subject is the chimps and has specifically changed the sentence (into a passive form) so that the chimps ARE NOT the subject anymore.
that's a pretty strong indication that the point is to de-emphasize the chimps, and to emphasize the cognitive process itself, as much as possible.

'so that' implies that chimpanzees are actually thinking, 'Hmm... if i exhibit curiosity, then i'll be able to catch on to my fellow chimps' behavior patterns. ...no！

just remember, your common sense will be integral in determining 'intended meaning' (since there are no rules for what is 'intended').

deny sb sth 双宾语
在gmat中 看大不看小 最重要的还是核心意思-谓语

more than three times as many 【independent institutions of higher education charge tuition and fees of under $8,000 a year 】as 【 ( independent institutions of higher education) charge over $16,000】.

先抓到结论会比较有帮助～

Conclusion: A recession in the future will not hurt teaching jobs at government-funded schools.

信息：解谜会使人智力提升，如果人们多社交，那么智力也会提升（if p, then q）
结论：社交也有使人们智力保持的效果（q is because of q）

又是“相关因果”而不是“因果”
推理文段的最后一句给出了“接触社会”和“智力技巧”的【统计关联】，结论句给出了此两者的【因果关系】。因此，推理文段为【相关因果推理】。
B选项：Correct. 很多影响人们智力的治疗也会提升人们的社会孤独。本选项同时提到了推理文段的因和果。给出了一个因果的方向问题，即，可能是因为人类智力的下降导致的社会孤独，而不是因为接触社会导致的智力保持。属于CQ3：因果方向问题。
C选项：很多人既精通社会交流又精通解决数学问题。本选项讨论的是人类的特点，不是推理文段的因果。

因果倒置，原文说越喜欢社交，智商越高
但B选项给出解释，是因为智商低的人在治疗的过程中，会让他们变得不喜欢社交
也就是说，是智商低的导致不喜欢社交，而不是喜欢社交导致智商变高

本题的情景相对比较复杂，我们仔细翻译一下。拥有17座赌场，M目前在某一州内运营了最多的赌场。虽然M意图扩张，但是A目前动作要比M快，它正在并购E（M/A/E都是运营赌场的机构）。为了完成对E的并购，A必须要卖掉5座赌场（因为政府有法律规定，一个county只能有一个赌场）。因为A并购之后会运营20座赌场，所以它将会变成该州最大的赌场运营机构。

脑筋急转弯：【已有的】赌场之间进行转手交易
A选项：Correct. Apex , Eldorado, 和Moneyland是该州唯三的三家运营赌场的机构。如果本选项成立，那么A在收购E的时候必须要卖出的那5间赌场只能卖给M了，自然M的运营赌场数就变成了17+5=22家了。反驳了结论。
C选项：有些州的县不允许开设赌场。A是【收购的】赌场，所以必然已经是"允许开设的县才会有的赌场了"，所以本选项和结论无关。

演绎推理：
A选项： G国的GNP在1963至1994年之间波动剧烈。推理文段中确实暗示了这段时间GNP有波动，但是这个波动是否剧烈我们就不得而知了。
D选项：Correct. 就算在数据被公布之前，该机构也有理由认为至少某些五年的预测是不准确的。显然地，因为G国每次5年的预测和对过去一年的回顾的数据都不同，所以无论信息是否公布，这个机构都有理由思考自己是不是预测出现了问题。

看到chasedream上一位ID是Deven1991的考友对D的解释，觉得靠谱——
在这个结果公布之前，机构已经意识到他们的五年预估是不准确的。以1968年为例，1963年预估1968年的，这个预估非常不准，后来他们一定是意识到了，那么在1969年猜测1968年的GNP的时候，他们调整了，因此猜得非常准。如果他们没有意识到自己的5年预估是错的，那么6年之后再猜测前一年，照样会是错的。所以，从他们猜测前一年非常准这一点能看出，他们一定是之前意识到自己的5年预估有问题，然后作出了调整。

文章里有一个gap，检查显示对G1963年五年以后的预测严重低估vs从1963年开始机构准确估计了G前一年的GNP。选项应该出现时间的概念

rash-adj. 轻率的，鲁莽的
'it would be rash to..."讲的是削弱

A选项：大部分被提供免费促销材料的兽医已经正在给他们的客户卖周边产品了。这表明兽医能从销售制造商的产品中获利，那它们更应该答应加入额外材料来增加销量
C选项：Correct. 不像很多兽医卖的竞品，这个制造商的产品也在宠物商店和超市被提供。如果答应推广了之后，人们可能被分流区其他地方买这些商品而不是通过兽医，兽医担心这会reduce their profits。生厂商想借助兽医的营销渠道做免费宣传，但兽医分不到这块蛋糕甚至既有利益还会被抢走！

答案（d）
目标：减少residual ash
方案：修改垃圾收集计划，多回收，使得【运垃圾焚烧的卡车数量减少一半】
求assumption，如果纠结选项，用否定法。正确选项取非，会反驳原文推理。
同样要注意assumption的定义：something must be true to draw the conclusion.

A. This year, no materials that city services could separate for recycling will be incinerated.→取非回收的垃圾也要焚烧，那么焚烧垃圾数量还是可以减少一半啊。回收的+不回收的焚烧垃圾之和是原来一半就行了，不能反驳原文目标。
D. The refuse incinerated this year will generate no more residual ash per truckload incinerated than did the refuse incinerated last year.→注意原文推理，“运垃圾焚烧的卡车一半”要实现目标“垃圾焚烧量一半”，gap是每辆卡车运的垃圾数。只有每辆卡车的垃圾数不变，才能使得推理成立。