The sentence is the immediate integral unit of speech built up words according to a definite syntactic pattern and distinguished by a contextually relevant communicative purpose.
From the point of view of their structure sentences can be divided into: two-membered (double-nucleus); one-membered (single-nucleus); complete; incomplete; simple; composite (compound, complex).
Simple sentences. Two-membered sentence contains two principle parts — the subject and the predicate. (Fleur had established immediate contact with an architect).
A two-membered sentence can be complete and incomplete. It is complete when it has a subject and a predicate (Young John could not help smiling). It is incomplete when one of the principal parts or both of them are missing, but can be easily understood from the context. Such sentences are called elliptical and they are mostly used in colloquial speech and especially in dialogue (Where were you yesterday? At the cinema).
One-membered sentence have only one principal part (Dusk — of a summer night).
Simple sentences, both two-membered and one-membered can be unextended and extended. A sentence consisting only of the primary or principle parts is called an unextended sentence. She is a student. Birds fly. Winter!
An extended sentence is a sentence consisting of the subject, predicate and one or more secondary parts (objects, attributes, adverbial modifiers). The two native woman stole furtive glances at Sarie.
Composite sentence is formed by two or more predicative groups. Being a polypredicative construction, it expresses a complicated thought reflecting two or more elementary situational events.
Each predicative unit in a composite sentence makes up...
a clause in it that corresponds to a separate sentence as a part of a contextual sequence.
Composite sentence displays two principal types of the connection of clauses — subordination and coordination.
According to the traditional view, all composite sentences are to be classed into:
compound sentences (coordinating their clauses),
complex (subordinating their clauses).
A compound sentence is a sentence which consists of two or more clauses coordinated with each other. In a compound sentence the clauses may be connected:
1) syndetically, i.e. by means of coordinating conjunctions (and, or, else, but, etc.) or conjunctive adverbs (otherwise, however, nevertheless, yet, still, therefore, etc.)
E.g. The darkness was thinning, but the street was still dimly lighted.
2) asyndetically, i.e. without a conjunction or conjunctive adverb.
E.g. The rain fell softly, the house was quiet.
The main semantic relations between the clauses connected coordinativety are copulative, adversative, disjunctive, casual, consequental, resultative.
A complex sentence is a polypredicative construction built up on the principle of subordination. Clauses in a complex sentence may be linked in two ways:
1) Syndetically, i.e. by means of subordinating conjunctions or connectives.
E.g. more and more, she became convinced that some misfortune had overtaken Paul.
2) Asyndetically, i.e. without a conjunction or connective.
E.g. I wish you had come earlier.
A subordinate clause may follow, interrupt or precede the principal clause.
According to the grammatical function subordinate clauses can be divided into: subject, predicative, object and adverbial (of time, place, purpose, cause, condition, concession, result, manner, comparison)
Structural Classification of Sentences