Subject = I Predicate = am your best friend
The subject is the one being talked about or the one who does the action in the sentence. It is usually (not always) the sentence starter. The predicate is the one that talks about the subject or the action of the subject. It starts with the verb.
Examples:Luffy (S) eats a lot. (P)Usopp (S) is not a coward. (P)CP-0 (S) consists of old but strong marines. (P)