The predicate is one part to a complete sentence, in every complete sentence there is a subject and predicate. Usually expresses what is said of the subject. Example: The child threw the ball, the subject is the child and the predicate is threw the ball.
When predicate is used in a sentence it is basically the verb, it has the closest meaning to predicate. Predicate indicates what the subject is doing or what it did. When used in a sentence it is often described as the action of the sentence. For paragraphs they can work because both a subject and predicate are needed to form complete sentences, which will help form the paragraphs. For sentence structure it describes what the subject is doing. The predicate basically tells what the subject is doing.
The predicate has great importance in grammar, it is the building blocks of sentences. Without a predicate there would not be any complete sentences, because every complete sentence needs a subject and predicate. Basic understanding of this topic is crucial to further enhance your writing. An example of a predicate, The child threw the ball, the subject is the child and the predicate is threw the ball. The predicate shows what action the subject is doing.
Jaeger, Gerhard (2001). "Topic–comment structure and the contrast between stage level and individual level predicates". Journal of Semantics 18 (2): 83–126.
Kratzer, Angelika (1995). "Stage Level and Individual Level Predicates". In Carlson, G.; Pelletier, F.J. (eds.), The Generic Book. Chicago: The University of Chicago Press.
"predicate." Online Etymology Dictionary. Douglas Harper, Historian. 30 Jan. 2012. <Dictionary.com http://dictionary.reference.com/browse/predicate>.