Once in a while, the GMAT will hurl a particularly nasty question in your direction, one that seems deliberately designed to make you feel uncertain about all of the answer choices. These sorts of questions will most likely include rare idioms, awkward phrasing, and suspicious pronouns to keep you off balance.
In these instances, sometimes your only defense is to plant your feet firmly on the ground, forget the rules, and pretend that you’re saying the sentence to your best friend. Pick whichever choice makes you feel the least ridiculous. However, this strategy should be reserved for those times when your knowledge of grammar isn’t helping much. Even if English is your second (or third) language, remember that using your ear and feeling the sentences on your tongue can still be one of your most powerful tools.
Take a look at the following question:
Students in the metropolitan school district lack math skills to such a large degree as to make it difficult to absorb them into a city economy becoming ever more dependent on information-based industries.
(A) lack math skills to such a large degree as to make it difficult to absorb them into a city economy becoming
(B) lack math skills to a large enough degree that they will be difficult to absorb into a city's economy that becomes
(C) lack of math skills is so large as to be difficult to absorb them into a city's economy that becomes
(D) are lacking so much in math skills as to be difficult to absorb into a city's economy becoming
(E) are so lacking in math skills that it will be difficult to absorb them into a city economy becoming
Pretty nasty, right? Reading each choice aloud helps to clear things out.
This question is testing the proper use of the idioms “such X that Y” and “so X that Y,” in which Y should be a clause. The original sentence uses the idiomatically incorrect to such a large degree as to, rather than “that.”
Choice C uses lack as a noun instead of a verb, so the noun students loses its corresponding verb. Lack as a noun would be correct if students were a possessive, but unfortunately it isn't. Choice D’s lacking so much in math skills as to be is unidiomatic because of the awkward insertion of much. Choice B is unnecessarily wordy and convoluted. Not only do we have to a large enough degree rather than simply so, but we also have an extra relative clause, economy that becomes, rather than simply economy becoming. In the absence of concrete grammatical errors, we need to look to stylistic concerns. Here, Choice E is far better stylistically. It uses the correct idiom "so X that Y" and is clear and concise. Choice E is correct.
Although at first glance their antecedents may seem unclear, the pronouns it and them in Choice E are not ambiguous. The pronoun it refers to the following phrase to absorb them into a city economy. What will be difficult? To absorb students into a city economy. Compare this to simple phrases such as "It is easy to bake a pie." The pronoun “it” refers to the action "to bake pie." What is easy? To bake a pie. The active version of this sentence is "Baking a pie is easy."
The pronoun them can logically refer only to students, since it does not make sense to describe skills as absorbed into a city economy. It’s important to keep an eye out for pronoun errors, but don't assume an answer choice is a weaker option just because you see pronouns.
Takeaway: Familiarity with correct idioms and proper pronoun usage will be invaluable come test day. That said, don’t forget that you can occasionally rely on your ear to steer you in the right direction.