In this sentence:
When he walked into the room, everyone stared at him.
"into the room" is a prepositional phrase but is "at him" also a prepositional phrase?
In this sentence:
When he walked into the room, everyone stared at him.
"into the room" is a prepositional phrase but is "at him" also a prepositional phrase?
Yes! Sentences can have multiple prepositional phrases, even in the same clause.
"When he walk" when he walked where? - "into the room"
"everyone stared" everyone stared where? - "at him".