A participial phrase starts with a participle. A prepositional phrase starts with a preposition.
A participial phrasei starts with either a participle or a particple. It acts as an adjective .
ex: The boy, frightened by the thunder , ran to his mother.
The phrase **frightened by the thunder** starts with a past participle. It describes the boy.
ex: Shivering with cold , the man wandered through the forest.
“Shivering with cold” starts with a present participle. It describes the man.
A prepositional phrase starts with a preposition and is followed by an object. A prepositional phrase acts either as adjective or adverb .
ex: The lady between the two men is my aunt.
“Between the two men” describes or modifies the lady. (Ask: Which lady? Ans: the lady between the two men) The phrase acts as adjective.
ex: The bird perched on the branch .
“On the branch” tells where the bird perched. The phrase acts as an adverb.
Note: Notice that a participle followed by a prepositional phrase becomes a participial phrase.
ex: 1. frightened by the thunder frightened — past participle by the thunder — prepositional phrase
ex 2. shivering with cold shivering — present participle with cold —prepositional phrase