Here's why:
* Predicate: The part of the sentence that tells us what the subject does or is.
* Verb Phrase: The part of the sentence that includes the main verb and any helping verbs.
Example:
* Sentence: The cat slept soundly on the couch.
* Subject: The cat
* Predicate: slept soundly on the couch
* Verb Phrase: slept soundly
The verb phrase "slept soundly" tells us what the subject (the cat) did.