Other forms: prepositional phrases
A prepositional phrase is a preposition plus a noun or pronoun. You can think of a prepositional phrase as “anywhere a cat can go.” A cat can walk “across the floor,” “under the table,” and “out the door.”
All prepositional phrases contain a preposition, a word that shows a relationship, plus a noun or pronoun. When you say, "The cat jumped over the wall," "over" is a preposition and “wall” is a noun, so "over the grass" is a prepositional phrase. The subject or verb of a sentence is never in the prepositional phrase, so prepositional phrases add flavor or specificity, but sentences can survive without them.