SUBJECT, PREDICATOR, OBJECT, COMPLEMENT, ADJUNCT
Subject and Predicator
The single independent clause (or simple sentence) is divided into two main parts, subject and predicate. Semantically and communicatively, the subject encodes the main participant (the plane/Tom) in the situation represented by the clause and has the highest claim to the status of topic. The predicate can consist entirely of the predicator, realized by a verbal group, as in 1 below, or the predicator together with one or more other elements, as in 2:
It is the predicator that determines the number and type of these other elements. Syntactically, the Subject (S) and the Predicator (P) are the two main functional categories. For the purpose of analyzing and creating discourse it is helpful to see how the predicate is made up, since this tends to be the most informative part of the clause. A first distinction can be made between elements that are essential and elements that are usually optional. This can be seen by comparing 1 and 2.
The two clause elements in 1, the Subject (the plane) and the Predicator realized by the verb landed are essential constituents. In 2 on the other hand, the predicate contains, as well as the predicator (disappeared), two elements, suddenly and after the concert, which are not essential for the completion of the clause. Although they are to a certain extent integrated in the clause, they can be omitted without affecting the acceptability of the clause. Such elements will be called Adjuncts (A).
