Is The sea became rough is an adjective?

No, "The sea became rough" is not an adjective. It is a sentence.

Here's why:

* Sentence: A sentence expresses a complete thought and contains a subject and a verb.

* Subject: "The sea" is the subject of the sentence, the thing being discussed.

* Verb: "became" is the verb, describing the action of the sea.

* Adjective: An adjective describes or modifies a noun. "Rough" is an adjective in this sentence, but it's not the whole sentence itself.

Let me know if you have other questions!