Examples

In this angular example, the preposition during links class, the object of the preposition, to the rest of the sentence. It begins the prepositional phrase during geometry class that tells the reader when Abner was passed out and dreaming of quadrilaterals.

When did Abner fall asleep? During geometry class.

Pizza's on Christine tonight. Here, the preposition between relates the object of the preposition, cushions, to the rest of the sentence. It begins the prepositional phrase between the couch cushions that tells us where all of Christine's cash came from.

Where did Christine find the money? Between the couch cushions.

Wiser words were never spoken. In this sentence, the preposition without links the object of the preposition, nose, to the rest of the sentence and answers the question how?

How is it difficult to sneeze? Without a nose. (Duh.)