GMAT Strategy

Example:

Scientists at the Los Alamos National Laboratory have succeeded for the first time in mining heat from the Earth's interior and producing energy on a commercial scale, enough for efficient generation of electricity and heating factories and homes.
(A) and producing energy on a commercial scale, enough for efficient generation of electricity and heating
(B) and producing enough energy on a commercial scale for electricity to be generated efficiently and to heat
(C) for energy production on a commercial scale, enough for generating electricity efficiently and to heat
(D) to produce energy on a commercial scale, enough for generating electricity efficiently and for heating
(E) to produce enough energy on a commercial scale for efficient generation of electricity and heat.

A and D have different meaning, but D is grammatically correct (A has parallelism issues efficient generation with heating

What do you attack first - Retaining the meaning of the original sentence or grammar?[/i]

Hey Zaara,

Great question and I'm really glad you brought this up - this problem illustrates the issue really nicely.

1) There's no official rationale for "protecting the meaning of the original sentence". The official Sentence Correction instructions don't say anything about that. And it doesn't make logical sense that the GMAT would test you on something like that if there's no logical reason that someone would think to do that. A is one of 5 answers - there's nothing special about A.

2) This sentence is a great example - if you're comparing meanings, D has a much more logical meaning than A does. If we use "and" (as A and B do), we're saying that this lab has succeeded for the first time in two different things: "mining heat from the Earth's interior" and "producing energy on a commercial scale". Which seems dubious...the first portion seems really innovative; the second is something that has been going on for decades if not centuries. But choice D links the two and that makes a lot of sense - for the first time, we've turned that interior heat into commercial energy. D has a logical meaning - if you look at A under a microscope it really doesn't.

3) Note also that the answer choice with the logical meaning is also grammatically correct. That's GMAT Sentence Correction - most grammatical errors that the GMAT explicitly tests are both grammar and meaning errors. A misplaced modifier is wrong because it's inaccurate. "High in saturated fat, I ate the donut anyway" is a modifier error mainly because it's illogical...I'm not high in saturated fat! There's a direct relationship between logic and grammar, so to answer your overall question the answer is "both". Poor grammar, especially in the GMAT context, leads to illogical sentences. And you can notice grammatical mistakes if you hold them up to the "does this even make sense?" test.

Most importantly here, know that "meaning" isn't some kind of weird twist that the GMAT is throwing out there. It's logic, and that's why it's in line with the GMAT's aims to test higher-order thinking. You're NOT responsible for matching the meaning of the original sentence. You ARE responsible for eliminating choices with illogical meanings.

I had to thank zaarathelab for posting this question and Brian for the explanation.

I just wanted to re-iterate the point that answer choice A is not special. Here is my analogy, "You are a judge on American Idol (is that still on TV)? You have five contestants. The first contestant comes out and sings in the single most annoying voice you have ever heard. Also, you hate the song and the guy singing it is wearing a clown costume. Now when the other singers come out are you going to count them down because they can sing? Or because they are not wearing a clown costume?"

Just as in the analogy it makes no sense to try to preserve the original meaning. What if the original meaning is illogical? Then that answer choice can be eliminated. Even if choice A is logical it could still be grammatically wrong and a different choice, with another also logical meaning could be grammatically correct.

Now it does make sense to preserve what the Official Guide calls the "intended meaning" what Brian refers to as the logical meaning but not the so-called original meaning.

After all, you are not going to get into Business School if you vote for the guy in the clown suit.

For more on this topic see my posting https://www.beatthegmat.com/the-truth-ab ... 76648.html

David and Brian, thank you so much for your tips.

After reading your posts, I developed a strategy for SC:

1. First, look at the complete sentence and eliminate answers that are 'blatantly' wrong based on illogical meaning or grammar
2. Next, look for other grammar errors that you couldn't spot in the first glance. Since most incorrect answer choices in gmat SC questions contain multiple errors, you will be able to come down to two if not one answer choice.
3. If there are two answer choices then there the only tricky possibility arises when both answer choices have different meaning but have correct grammar. If one of them is A, pick A so that we retain the meaning. If not, then look for the meaning closest to answer choice A.

Both answer choices have same meaning and correct grammar- Not possible (one will have to look closely)

Let me know what you guys think.

Hey Zaara,

Really well done with steps 1 and 2 of your process - that's exactly how I'd do it.

Your Step 3 is flat-out-wrong, though. As the problem at the top of this thread proves, choice A could very well have an illogical-and-therefore-incorrect meaning. DO NOT protect the meaning of A. Your step 3 should be to "consider the meanings of both answers and decide which one is more logical".

This is a classic parallelism problem, touching upon simple vs complex gerunds. Simple gerunds such as "verb-ing" should never be parallel to complex gerunds such as "the/a/an+ verb-ing + of the..". Once you know this, B starts to look awkward and unparallel.

Mining heat from X to produce Y

"and" --> incorrect here.
See why "and" is inappropriate here
have succeeded for the first time in mining heat from the Earth's interior and producing energy on a commercial scale
=
succeeded for first time in doing X and doing Y.

above sentence is grammatically correct.. but logically doesn't make sense.

it means first time producing energy on commercial scale but that's not intention of author.
..[ energy might be produced on commercial scale by other methods ...]
first time in doing X from Z to product Y.
Between D and E.
D looks better.

A. and producing energy on a commercial scale, enough for efficient generation of electricity and heating --> Misplaced modifier. The modifier is modifying "commercial scale" where it should be placed near "energy". Also, "for efficient generation of electricity" and "heating" are not parallel. It should have been "for generating electricity and heating ". This sentence also perverts the intended meaning. The sentence should have been "Scientists at the Los Alamos National Laboratory have succeeded for the first time in mining heat from the Earth's interior to produce energy on a commercial scale,"

B. and producing enough energy on a commercial scale for electricity to be generated efficiently and to heat--> again it should be "to produce" and the underlined parts are not parallel.

C. for energy production on a commercial scale, enough for generating electricity efficiently and to heat--> underlined parts are not parallel.
D. to produce energy on a commercial scale, enough for generating electricity efficiently and for heating--> looks good. Underlined parts are parallel and "and" replaced by "to".

E. to produce enough energy on a commercial scale for efficient generation of electricity and heat --> underlined portion is wrong. It should be a noun / noun form (gerund) - "heating". Option E also changes the intended meaning of the sentence. Placement of enough is awkward here.
It should be D.