Theoretical grammar of english

21. Classification of sentences based on their structure. The simple sentence. The composite sentence.
Structurally sentences are divided into:1) simple (contains only 1 subject-predicate unit) or composite (more than one), 2) complete or incomplete (elliptical)-distinguished by the presence or absence of word-forms in the principal positions of 2-member sentences, 3) two-member (two principal parts-the subject and the predicate) or one- member (1 principal part which is either subject, or the predicate). These 3 classifications are based on different approaches to the structural organization of sentence & reflect its different aspects.
The simple sentence. 1) Two-member sentences. The basic pattern is one subject-predicate unit. Thus it has 2 main positions: those of the subject and the predicate. There are several variations of this pattern-depend on the kind of the verb occupying the predicate position. This verb may be transitive, in~, ditransitive or a link verb. Sentences may be unextended (John is clever) and extended (John learned French). A sentence may be extended, not only by obligatory elements but also by optional ones (attributes, certain kinds of prepositional objects, adverbial modifiers) ~John ran quickly to me.
2) One-member sentences: a) nominal b) verbal. Nominal-the principal part is expressed by a noun, they state the existence of the things. They are typical of descriptions and may be unextended (Silence. Midnight) &extended (English spring flowers!). Verbal-the principal part expressed by a non-finite form of the verb, infinitive or gerund. Mostly used to describe different emotional perceptions of reality. (To think of that! Living at the mercy of a woman!).
The composite sentence is a sentence consisting of 2 or more clauses. In its structure a clause is similar to a simple sentence, but unlike a simple sentence it forms part of a bigger syntactical unit. Clauses may be joined by means of coordination (a compound sentence-The door opened & 2 men came in) or subordination (a complex sentence ~ I have come to u, because I know that u can help me). Coordination is a way of linking grammatical elements to make them equal in rank. Subordination makes one of them dependent upon the other. A compound sentence may contain coordination, clauses extended by subordinate clauses - a compound-complex sentence. (Pooh was very proud when he heard this and Piglet noticed it at once). A complex sentence may contain subordinate clauses joined by means of coordination - a complex sentence with homogeneous subordinate clauses (I know that he has come and that he is out of money).