In addition to these necessary elements of the sentence, words or groups of words may be added to make the meaning of any one of the elements more exact. Such additions are known as modifiers. The word-groups which are used as modifiers are the phrase and the clause.
[The thrush, sings in the pine woods (phrase). The wayfarer who hears the thrush is indeed fortunate (clause).]
Both the subject and the predicate may be unmodified:
[Bees buzz]; both may be modified: [The honey bees buzz in the clover]; one may be modified and the other unmodified: [Bees buzz in the clover].
The unmodified subject may be called the simple subject, or, merely, the subject. If modified, it becomes the complete subject.
The assertive element, together with the attribute complement, if one is present, may be called the simple predicate. If modified, it becomes the complete predicate.
Some grammarians call the assertive element, alone, the simple predicate; modified or completed, the complete predicate.
+16. Classification of Sentences as to Purpose.+—Sentences are classified according to purpose into three classes: declarative, interrogative, and imperative sentences.
A declarative sentence is one that makes a statement or declares something: [Columbus crossed the Atlantic].
An interrogative sentence is one that asks a question: [Who wrote Mother Goose?].