Are There Set Rules for Answering GMAT Sentence Correction Questions?

SAT WorryThe other day I was working with a tutoring student on Sentence Correction when she expressed some understandable frustration: when we did Quantitative questions together, she said, she felt like she could rely on ironclad rules that never varied (the rules for exponents don’t change depending on the context of the problem, for example), but when we did Sentence Correction, the relevant rules at play in a given question seemed less obvious.

Was there a way, she wondered, to view Sentence Correction with the same unwavering consistency with which we view Quantitative questions? While I understand her frustration, the answer is, alas, an unqualified “no.” English is far too complex for us to boil down Sentence Correction to a series of stimulus-response reflexes. Context and logic always matter.

To see why we can’t go on autopilot during Sentence Correction questions, consider the following problem:

Not only did the systematic clearing of forests in the United States create farmland (especially in the Northeast) and gave consumers relatively inexpensive houses and furniture, but it also caused erosion and very quickly deforested whole regions. 

A) Not only did the systematic clearing of forests in the United States create farmland (especially in the Northeast) and gave consumers relatively inexpensive houses and furniture, but it also

B) Not only did the systematic clearing of forests in the United States create farmland (especially in the Northeast), which gave consumers relatively inexpensive houses and furniture, but also

C) The systematic clearing of forests in the United States, creating farmland (especially in the Northeast) and giving consumers relatively inexpensive houses and furniture, but also

D) The systematic clearing of forests in the United States created farmland (especially in the Northeast) and gave consumers relatively inexpensive houses and furniture, but it also

E) The systematic clearing of forests in the United States not only created farmland (especially in the Northeast), giving consumers relatively inexpensive houses and furniture, but it

If you fully absorbed the class discussion about the importance of parallel construction, you probably noticed an indelible parallel marker here: “not only.” Okay, you think. Any time I see not only x, I know but also y should show up later in the sentence.

This isn’t wrong, per se, but the construction “not only/but also” is only applicable in certain circumstances. So before we jump to the erroneous conclusion that this is the construction that is called for in this sentence, let’s examine its underlying logic in more detail.

Take the simple example, “On the way to work, I not only got stuck in traffic, but also….” Think about your expectations for what should come next in this sentence – getting stuck in traffic was the first unfortunate thing to happen to this hapless subject, and we’re expecting a second unfortunate event in the latter part of the sentence. Not only/but also is appropriate when we’re talking about similar things.

Now consider the construction. “On the way to work, I got stuck in traffic, but…” Now our expectations are markedly different – the second half of the sentence is going to contrast with the first. We’re expecting something different.

Let’s go back to our GMAT sentence. We’re comparing the consequences of the clearing of forests. First, the clearing “created farmland and gave consumers inexpensive houses” (good things). However, it also “caused erosion and deforested the region” (bad things). Because we’re comparing two very different consequences, the construction “not only/but also” – which is used to compare similar things – is inappropriate. Now we can safely eliminate answers A, B and E.

That leaves us with C and D. First, let’s examine C. Notice there’s a participial modifier in the middle of the sentence set off by commas, and a sentence should still be logical if we remove these modifiers. We would then be left with, “The systematic clearing of forests in the United States, but also caused erosion and very quickly deforested whole regions.” This clearly doesn’t work – the initial subject (the systematic clearing) has no verb, so C is wrong. This leaves us with answer choice D, which is the correct answer.

Takeaway: though noticing common constructions on Sentence Correction problems can be helpful, we can never go on autopilot. Ultimately, context, logic, and meaning will always come into play. Before you select any answer, always ask yourself if the sentence is logically coherent before you select it. If you want to ace the GMAT, turning off your brain is not an option.

*GMATPrep question courtesy of the Graduate Management Admissions Council.

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By David Goldstein, a Veritas Prep GMAT instructor based in Boston. You can read more articles by him here.