Identify the prepositional phrases in the following sentence:

As I walked along the beach I saw a couple playing frisbee with their children

"Along the beach" and "with their children" are the two prepositional phrases in this sentence, A prepositional phrase is a group of words that lacks both a verb and a subject but is a coherent part of speech. A common construction has the preposition followed by an article and a noun. So "along the beach", "under the table" and "inside the house" are all examples of prepositional phrases.