Greetings, grammar experts!
Consider: Under the deep blue sea, fish swam.
'Under the deep blue sea' is not a dependent clause because it has no verb and is therefore not a clause at all. It is an adverbial prepositional phrase modifying swim (I think.)
Is this prepositional phrase considered part of the predicate of the sentence even though it has a comma after it?
In other words, is the predicate.... "swam"
or is the predicate... "Under the deep blue sea, ____ swam."
Perhaps I am wrong to believe this is a grammatically correct sentence?
Is it considered part of the independent clause, or do you just say this is a prepositional phrase followed by a common and an independent clause?