Pronouns come up frequently as a grammatical issue on GMAT Sentence Correction. Here’s what you need to know about them, excepted from my book on GMAT Sentence Correction.
Pronouns are words that stand in for nouns. “It”, “he”, “they” are all pronouns. “Its”, “his”, and “their” are also pronouns.
Pronouns need a clear antecedent, which is the word they’re standing in for. For instance, in the previous sentence, “they’re” stands in for “pronouns”.
Pronouns need to match the person of their antecedents. So, “The boy ran, then he threw the ball.”
The same rules apply to verb person and to pronoun person. Group nouns take singular pronouns, and we always have to pay attention to what the pronoun is referring back to.
In the GMAT, “it” can never refer to a person, and “they” can never be singular. Be careful, as “they” and “their” are frequently used for singular pronouns in conversational English.
If we can avoid using pronouns, we should. So, for instance, the GMAT prefers, “The boy, tired of walking his dog, let the leash go,” to “the boy was tired of walking his dog, and he let the leash go.” They both mean the same thing, but the first avoids the use of a pronoun.
If you’re looking for practice with GMAT pronouns including detailed explanations, you should get my Sentence Correction book.