Do you mean "what part of speech?"
If so, adjectives, adverbs, conjunctions, and prepositions (blue / quickly / and / in ) can be neither subject nor predicate on their own, though they can be in either subject or predicate.
s u b j e c t | p r e d i c a t e
The blue car | drove quickly past the green and yellow mailbox. -- above mentioned parts of speech in bold. Not in bold -- 2 nouns (car, mailbox) and 1 verb (drove).
A phrase contains either a subject or a predicate, but not both. For example, "under the table" is a phrase that functions as neither a subject nor a predicate.
clause
This is known as a sentence fragment. It lacks either a subject, a predicate, or does not express a complete thought on its own. Sentence fragments can occur due to incomplete construction or lack of context.
A phrase contains either a subject or a predicate but not both. A subject is present in a noun phrase, while a predicate is found in a verb phrase. An example of a phrase with a subject but no predicate is "the big tree."
A group of words without a subject or predicate is a phrase.
A phrase contains either a subject or a predicate, but not both. For example, "under the table" is a phrase that functions as neither a subject nor a predicate.
clause
A phrase does not necessarily need to have both a subject and a predicate; it is a group of words that may not express a complete thought. For example, noun phrases ("the tall tree") or prepositional phrases ("in the park") lack a subject-predicate structure. In contrast, a clause, which can be independent or dependent, does contain both a subject and a predicate.
This is known as a sentence fragment. It lacks either a subject, a predicate, or does not express a complete thought on its own. Sentence fragments can occur due to incomplete construction or lack of context.
This is called a phrase.
a group of words containing a subject and predicate
A phrase contains either a subject or a predicate but not both. A subject is present in a noun phrase, while a predicate is found in a verb phrase. An example of a phrase with a subject but no predicate is "the big tree."
A group of words without a subject or predicate is a phrase.
To use a word group to make a complete sentence, you can start by ensuring that the word group contains a subject and a predicate. The subject is the noun or pronoun that the sentence is about, and the predicate is the verb that describes the action or tells something about the subject. Combine the subject and predicate to create a complete thought that conveys meaning.
A clause is a word group that contains a verb and its subject and that is used as a sentence or part of a sentence, whereas a phrase is a group related words that is used as a single part of speech and that does not contain both a verb and its subject.
you need subject (Who?) and predicate (verb referring to the subject) and you can add an object (like When? Where? Waht?,...) eg: You [Subject] go [predicate] to school [object].
phrases