Here's why:
* Gerund Phrase: A gerund phrase is a group of words that acts as a noun and begins with a gerund (a verb ending in "-ing" used as a noun).
* "Announced" in this case is the past participle of the verb "announce," not a gerund.
How to tell the difference:
* Gerund: "Announcing" would be the gerund form of the verb.
* Past Participle: "Announced" acts as an adjective modifying "next week."
Example of a Gerund Phrase:
* "Singing in the shower" is a gerund phrase because "singing" is a gerund acting as the noun subject of the sentence.
The phrase "announced next week" is actually a participial phrase acting as an adjective modifying "week".