The term modifier refers simply to a word or phrase that modifies something else in a sentence; for example, an adjective can be a modifier for a noun or pronoun. A misplaced modifier is considered misplaced because it appears too far from the word or words it modifies, thus making the sentence unclear or inaccurate. As a general rule, you should place a modifier as close as possible to the sentence element it modifies.
The following example illustrates the confusion that can arise when it is unclear which word a modifier describes.
Beth was told about the decision by Sam’s manager.
In this case, the problematic modifier is the prepositional phrase by Sam’s manager. What it refers to is unclear. Did Sam’s manager make a decision, and did someone other than the manager — a person not mentioned in this sentence — tell Beth about it? Or did Sam’s manager tell Beth about a decision made by someone else? Since it is unclear, the sentence must be rewritten:
Sam’s manager told Beth about the decision.
Beth was told about the decision made by Sam’s manager.
The word only is often a problematic modifier, frequently misplaced in both spoken and written English. It should generally appear right next to the word it is modifying. Compare these two sentences:
Last night I only ate three pieces of lettuce.
Last night I ate only three pieces of lettuce.
Both sentences could technically be correct, but the second sentence is far more likely to be the version the writer intended. Only functions as an adverb here and correctly modifies three (which is in this case an adjective).
If only appears before the verb, as in the first sentence of the pair, it means that last night you did nothing but eat lettuce. You didn’t read. You didn’t return phone calls. You didn’t watch television. All you did was eat lettuce — and apparently you did that very slowly, since you got through no more than three leaves of it.