A modifier can be a single word, a phrase, or a clause whose function is to add information to the sentence. Examples of single word modifiers.
In the first example, the modifier describes the dog (tired dog). Words that modify nouns are called adjectives. In the second example, the modifier describes an action (joyously clapped). These words which modify verbs are called adverbs.
There are two types of modifiers - noun modifiers and verb modifiers. Adjectives modify nouns, and longer phrases or clauses that modify nouns are also called adjectival phrases or clauses. Adverbs modify verbs, and longer phrases or clauses that modify verbs are also called adverbial phrases or clauses.
A phrase is a group of grammatically linked words that do not express a complete thought. A phrase does not contain a subject and a verb. Examples of phrases:
Both of the phrases above function as modifiers because they add information to the sentence. The first phrase is called a participial phrase. A participle takes a verb and turns it into an adjective. In this example, the verb to turn is transformed into the participle turning. This phrase modifies the noun in the sentence, Jones. The second example employs a prepositional phrase. It modifies the verb ran, telling us where the children went.
When using modifiers, there is some discretion about where to place them in the sentence. Most of the questions on modifier on the GMAT involve noun modifiers. Verb modifiers have little loose rules. There is more freedom in where a verb modifier could be placed in a sentence.
Joyously is verb modifier. Both sentences express the same meaning. However, with noun modifiers, moving the modifier changes the meaning of the sentence or makes the meaning unclear. Consider this sentence:
Now, move the modifier around like so: The dog limped into the tired yard.
The meaning of the sentence has now changed (considering that a yard cannot be tired). Thus modifiers must be placed in such a way as to preserve the meaning of the sentence and avoid ambiguity. As a general rule, a modifier should be as close as possible to the noun (or verb) modified. This rule is also known as Modifier Touch Rule as it touches the noun in the sentence. Modifiers that are positioned in such as way as to create either nonsensical meanings or ambiguous meanings are called misplaced modifiers.
A group of words that contains both a subject and a verb is called a clause. Any clause that can stand alone is called an independent clause. However, not all clauses can stand alone, as the following example shows:
The dependent clause, when she left the room, could not stand alone as a sentence. Like modifying phrases, it is important that dependent clauses be used in a way that preserves the clarity of the sentence and prevents ambiguity.