The main sentence types in English.

There exist different perspectives on defining the term “ sentence ” [4]:

1) Logical: a sentence is a proposition expressed by words.

2) Structural: the sentence is a subject-predicative structure.

3) Phonological: a sentence is a flow of speech between two pauses.

4) Orthographic: a unit contained between a capital letter and a full stop.

There are also definitions which take into account most of the sentence characteristics:

1) “A sentence is the central syntactic construction used as the minimal communicative unit that has its primary predication, actualises a definite structural scheme and possesses definite intonation characteristics” [5].

2) А sentence is the immediate integral unit of speech built up of words according to a definite syntactic pattern and distinguished by a contextually relevant communicative purpose [43].

The main features of the sentence are: integrity, syntactic independence, communicative functionality, predicativity, modality, grammatical, semantical and intonational completeness.

The main criteria for sentence classification:

1. Sentence structure;

2. The existence of all parts of the sentence;

3. Communicative aim of the speaker;

4. The character of grammatical (syntactical) presentation;

5. Expressiveness.

Let us expand on each of this classifications.

1. Sentence structure

Sentence structure classification is based on the number and types of clauses. A clause is “a group of words that forms a part of a sentence and has Subject and a Predicate of its own...” [51]. They fall into the following types:

Independent clause – a group of words made up of a subject and a predicate. It can stand alone as a sentence.

Dependent (subordinate) clause – a group of words that has both a subject and a verb but cannot stand alone as a sentence; they include adverb clauses, adjective clauses, and noun clauses.

Pseudo-subordinate clause – a rare type of clause introduced by the conjunctions if and that and used emphatically: If only I were young again!

A clause includes the finite verb, expressing the basic predicative meaning of the sentence and performing the function of the predicate, and the subject combined with it, which form the so-called “ predicative line ”. On the basis of predicative line presentation, sentences are divided into monopredicative(simple), and polypredicative, i.e. composite and semi-composite.

Monopredicative sentence has one subject-predicate unit and is represented by an independent clause with no subordinate clauses.

Polypredicative sentences fall into 4 types [19]:

1)Complex sentences, that consist of one independent clause and one or more dependent ones, which are joined together by subordinate conjunctions (after, although, though, as, because, before, if, since, until, till, when, where, whether…. or not, which/that, while) or asyndetically. The clauses are united on the basis of subordinative connections (hypotaxis).

2) Compound sentences, in which the clauses are connected on the basis of coordinative connections (parataxis). The clauses are arranged equipotently and are linked by the coordinating conjunctions (and, but, so, either, or, neither, nor, then and yet) or asyndetically.

3) Compound-complex sentences have two main clauses and one or more subordinate clauses introduced by subordinating conjunctions and joined by a coordinating conjunction.

4) Composite sentences with predication, in which one predication is expressed, word for word, as attributive to another predication by means of a subordinating conjunction: It looks like rain.

The clauses of polypredicative sentences may be joined:

1. asyndetically — by intonation or punctuation and without conjunctions;

2. syndetically — by conjunctions.

There also can be distinguished transitional types of sentences [18], in which one predicative line is represented by a semi-predicative construction (a construction made up by a non-finite form of the verb & a substantive element denoting the subject or object of the action expressed by the non-finite form of the verb).

Transitional types of sentences
semi-complex	semi-compound
position-sharing	direct linear expansion	coordinated subjects	coordinated predicates	coordinated objects	coordinated adverbial modifiers
subject-sharing	object-sharing	attributive complication	adverbial complication