Sentence correction questions present a statement in which words are underlined. You have to select from the answer options the best expression of the idea or relationship described in the underlined section. The first answer choice always repeats the original phrasing, whereas the other four provide alternatives.
In some cases, the original phrasing is the best choice. In other cases, the underlined section has errors that require correction. These questions require you to be familiar with the stylistic conventions and grammatical rules of standard written English and to demonstrate your ability to improve incorrect or ineffective expressions.
The key to performing well on sentence correction questions is to approach them systematically.
Determine the nature of the original sentence's error (if one exists). If a sentence has more than one error, focus on one error at a time. If you can, come up with a quick idea of how to fix the error before you look at the answers.
Skim through the answer choices and eliminate any choices that don’t correct the error.
Eliminate answer choices that correct the original error but add a new error or errors. You should be left with only one answer that fixes the original problem without creating new errors.
Reread the sentence with the new answer choice inserted just to make sure that you haven’t missed something and that the answer you’ve chosen makes sense.
When you read the sentence-correction question, pay particular attention to the underlined portion and look for at least one error.
If you don’t see any obvious errors, read through the answer choices just to make sure they don’t reveal something you may have missed. If you still don’t see a problem, choose the first answer choice.
If you spot an error in the underlined portion, read through the answer choices and eliminate those that don’t correct it. If you see more than one error in the underlined portion of the statement, begin with the error that has the more obvious correction.
For example, if the underlined portion has both a rhetorical error and an error in subject-verb agreement, begin with the error in subject-verb agreement. Eliminating answer choices that don’t address the agreement problem is quick and easy. After you have eliminated the choices that don't fix the obvious error, move on to the other error or errors. Comparing rhetorical constructions in answer choices can take a while, so eliminating choices before this step saves you time.
The next step is to eliminate answers that create new errors. A new error in an answer choice usually isn’t the same type of error as the original one.
You should end up with only one answer choice that corrects the existing errors without creating new ones. If you end up with two seemingly correct answer choices, read them both within the context of the original sentence. One will have an error that you have overlooked.