Modifiers are words, phrases, or clauses that provide descriptive detail about other words, phrases, or clauses. Adjectives (the red car, the happy child) are modifiers, as are adverbs (he runs quickly).

Adjectives modify nouns.
Adverbs modify verbs or adjectives.

Sometimes, however, entire phrases can be used as modifiers. Modifying phrases function the same way as single-word modifiers do, but because they're often buried in an already complicated sentence, they can be harder to spot than adjectives and adverbs. Lengthy modifiers therefore appear quite often on the GMAT. This chapter will give you more detailed tips and methods by which to recognize these kinds of modifiers on the GMAT. But for general reference, keep this rule in mind: Any part of a sentence that adds extra information can be considered a modifier.

Our list of common modifier errors, begins with adjectives and adverbs, and then considers phrases and clauses.

1. SUBJECT-VERB AGREEMENT

Adjectives and Adverbs