Because the GMAT is a standardized test, understanding the structure of certain questions types can give you an advantage on test day.  Specifically, by understanding how the test maker is setting up a type of problem, you can move through the problem more quickly, giving yourself time for more advanced problems.

On GMAT sentence correction questions, you will be given a sentence, part of which is underlined.  In order to answer correctly, you must choose the answer that makes the underlined portion grammatically correct.

The first pattern to keep in mind in these questions involves answer choice (A).  The first answer in sentence correction problems will always be the same as the original sentence.  Thus, the first way test takers can save time is by not reading this answer choice, as it mirrors the underlined portion in the problem.

The second way to save time is to remember that you do not need to consider each answer choice in its entirety.  Instead, you can simply group the answer choices according to the differences between them and eliminate.  For an example of how this is done, let’s consider to following problem:

Noting that its revenues had fallen due to a recent prolonged slump in CD sales, the music-store chain announced that it would be forced to raise prices at all of its outlets.

(A) its revenues had fallen due to a recent

(B) its revenues have fallen due to a recently

(C) its revenues are falling due to a recently

(D) their revenues are falling due to a recent

(E) their revenues had fallen due to a recent

Instead of considering the answer choices in full, you should group the choices into those using the pronoun ‘its’ and the pronoun ‘their.’  Because (D) and (E) both use the incorrect ‘their’ – the pronoun’s antecedent is the singular ‘the music-store chain’ – both can be eliminated.  Next, you should identify that of the remaining options only (A) uses the correct verb tense.  (A) uses ‘had’ to indicate something happening in the past before something else in the past, which (B) and (C) do not do.  Therefore, you eliminate (B) and (C), leaving (A) as the correct answer.