Final answer:
A predicate by itself does not have a truth value, as it requires the subject and additional information to determine its truth or falsehood.
Step-by-step explanation:
A predicate is the portion of a sentence that provides the description or characterization of an object or name. It helps clarify statements and is an essential component of a sentence. However, a predicate by itself does not have a truth value as it requires the subject to determine its truth or falsehood.
For example, let's take the sentence 'The cat is on the mat.' In this sentence, 'The cat' is the subject, and 'is on the mat' is the predicate. By itself, the predicate 'is on the mat' cannot be evaluated for its truth value. The truth value of the entire sentence depends on whether or not the subject, 'The cat,' is indeed on the mat.
Similarly, in the given options, sentences like 'It is raining,' 'The sky is blue,' 'I am hungry,' and 'The cat is on the mat' all have predicates that require the subjects and additional information to determine their truth value.