The modifier is the word or clause that, when placed within a sentence, has the ability to explain a term or other clause present in the same sentence. In the sentence presented in the question above, the term "library book" is the modifier and is misplaced in the sentence, leaving it confused and lacking cohesion. In this case, we can say that the modifier was misplaced. The correct sentence would be: Philip had read three chapters of the library book when he discovered that it was overdue.
