Both GMAT rules and GMAT preferences will help you find the correct answer on sentence correction questions. However, they are very different and need to be used differently. An example of a GMAT rule would be:
An antecedent and its pronoun must agree in number
This means that: “The professor had to finish grading their papers” would be incorrect grammar, because “their” is a plural pronoun and “professor” is singular. Even though in colloquial English, we often use they to refer to a single person if we don’t know his or her gender, this is never correct on the GMAT.
An example of a GMAT preference is:
GMAC prefers concise answer choices
This information should be used when you are down to two grammatically correct answers, then you can pick the more concise one. However, you should not use this information to eliminate wrong answers. For example, don’t simply go through the answer choices and pick the shortest one.
The key difference in how you use GMAT grammar preferences vs GMAT grammar rules is that rules should be used to eliminate incorrect answer choices in the beginning, while GMAT grammar preferences should be used when you have eliminated all but the final two.
Here are some examples of GMAT rules and preferences:
- An antecedent must exist and agree with its pronoun in number
- A subject and its verb must also match as far a plural and singular
- A noun and its modifier must touch
The important GMAT preferences include:
- Concise wording is better than wordy answer choices
- A verb is preferred to an action noun
- Active voice is preferred to passive voice
- The “ing” form of a verb is preferred over the infinitive