* Gerund Phrases are verb forms ending in "-ing" that act as nouns. For example: "Swimming is my favorite activity."
* "Laughing" in this phrase is a participle modifying the noun "boy."
* "Sat down" is a verb phrase, the action the boy is doing.
Correct Breakdown:
* Laughing boy: This is a noun phrase, with "laughing" acting as an adjective modifying "boy."
* Sat down: This is a verb phrase, showing the action the boy performs.
Therefore, "laughing boy sat down" is not a gerund phrase, but rather a complete sentence with a noun phrase as the subject and a verb phrase as the predicate.