A simple predicate is a part of a sentence that will link up with the main subject. It is usually a verb as it tells the reader what the subject is 'doing.' For example in the sentence, "I read the book aloud in the classroom," the subject is "I." The linking verb or 'simple predicate' that is telling the reader what the subject is doing is "read."
A complete predicate is the phrase or words that go on to give more detail or offer more description on the simple predicate. So, in the example mentioned above, the complete predicate would be "read aloud," as this is describing in more detail how the action was carried out.
Some people may also think it is easier to understand the complete predicate as thinking of it as being all the words and phrases that come in the sentence after the verb has already been introduced. In the above mentioned example the simple predicate would remain as the verb "read," and the complete predicate would be "read aloud in the classroom."
Certainly, the sentence could be arranged in another way with the description coming before the verb i.e.: "Loudly, I read in the classroom." In this situation, the principles would still remain the same.
