The Sentence Correction portion of the GMAT Verbal tests grammar and mechanics. About 15 of the 41 Verbal questions are SC, so SC constitutes the majority of the three verbal question types. With SC questions, you’ll be presented with a sentence, part of which or all of which is underlined. You’ll have five choices that rephrase the underlined portion, the first of which repeats the original. Your task, as expected, is to choose the best option. What does “best” mean in this case? According to the GMAT, the question tests “correctness and effectiveness of expression,” and you should pay attention to “grammar, choice of words, and sentence construction.” The answer should be “clear and exact, without awkwardness, ambiguity, redundancy, or grammatical error.”

That seems like a lot to ask, and indeed it is. Luckily, there is a limited number of specific errors that SC questions test, and it’s crucial to learn each one. Before you learn these common errors, though, you need to follow a certain plan of action. Here’s how to attack an SC, step by step:

1. Read the whole sentence slowly and carefully. We all have different reading speeds, but as a good rule of thumb, you’ll want to read the sentence significantly slower than you would read a novel. For you fast readers who don’t subvocalize as you read, you might want to try subvocalizing SC sentences; sometimes it’s best to hear the mistake rather than see it.

2. If you notice what looks like an error in the underlined portion, try to identify the type of error before you move on to the answer choices. Why? The test writers are clever, and many of the incorrect choices appear correct.

Remember, there are basically three ways an  answer can be wrong:

- It violates a grammar rule.

- Its wording is unclear.

- Its wording is nonstandard (these will often sound incorrect)

3. If the underlined portion appears correct, make note of it, but read every answer choice carefully before you rule it correct.

4. Examine answer choices individually. If you found an error in the original, eliminate choice A. If any of the answer choices repeat that error (and they often do), then eliminate those answers. Try to look for additional errors in the answer choices and spot other choices that repeat those errors. It’s imperative that you group answer choices together based on common errors; this strategy save you precious time.

If you were unable to find an error in the original sentence, search for errors in the answer choices to quickly eliminate them. In other words, when you can’t find the error in the original, never try to search for the correct sentence –always work by elimination. If you can spot errors in each choice, then you should choose A as the answer.

5. If you’re down to two choices that both seem fine, identify the differences between the sentences, and only examine these differences. The error will always lie in that portion.

A systematic method is just as necessary to solve SC’s as is knowledge of the grammar rules. Wrong answer choices are designed to be seductive, so firmly adhere to a system to get the job done.