A preposition is not a modifier. The only parts of speech that are modifiers are adjectives and adverbs. A preposition shows the relationship that exists between certain words in a sentence. The word preposition comes from two Latin words that mean "placed before." A preposition is a word that is placed before some noun or pronoun. It shows the relationship that exists between that noun or pronoun and some other word in the sentence. When we say "a bag for the mail," the word "for" is a preposition. It shows the relationship between bag and mail. The word "mail," which follows the preposition, is called the object of the preposition.

In the sentence, "The accident occurred on the bridge," the word on is a preposition. The preposition on is followed by the word bridge, which is called the object. The entire group of words, on the bridge is called a prepositional phrase. The preposition on shows the relation between the noun bridge and the verb occurred. The entire phrase on the bridge tells where the accident occurred.

As the teacher moves around the room try to describe where the teacher is with as many prepositions as are correct.

Avoid the over use of prepositions. Some students might say, "A car of the color green." Instead use "a green car."