1. the subject of theoretical grammar its relations to other branches of linguistics

43. The structural classification of sentences.
One traditional scheme for classifying English sentences is by the number and types of finite clauses: sentences are divided into simple and composite, the latter consisting of two more clauses. Composite sentences will be the subject of the next lecture, and here we will focus on classifications of simple sentences.
Simple sentences are usually classified into one-member and two-member. This distinction is based on a difference in the main parts of a sentence. One- member sentences do not contain two such separate parts; in these sentences there is only one main part (e.g. Silence!)Such sentences contain neither the subject nor the predicate. Instead there is only one main part. It is a disputed point whether the main part of such a sentence should, or should not, be termed subject in some cases, and predicate, in others.
One-member sentences should be kept apart from two-member sentences with either the subject or the predicate omitted, i. e. from elliptical sentences.
Ellipsis in sentence-structure is a natural syntactic process in linguistic development presented as normal practices in many, if not all, languages. In terms of traditional grammar, elliptical sentences are generally identified as sentences with the subject or predicate missing. Some grammarians hold another point of view recognising ellipsis also in sentences where the secondary parts of the sentence are felt as missing. Such was A. M. Peshkovsky' s treatment of elliptical sentences in Russian. This view was also shared by B. Ilyish, L. S. Barkhudarov and D. A. Shtelling in regards to English. And this is the view we shall adhere to in our course. So an elliptical sentence is a sentence with one or more of its parts left out, which can be unambiguously inferred from the context. The main sphere of elliptical sentences is dialogue.
e.g. Where are you going? - To the movies.
In terms of structure the following types of elliptical sentences are singled
out:
omission of the subject: e.g. Hope to see you soon.
omission of the predicate in patterns with there is, there are, e. g. Too many mistakes, I am afraid.
omission of auxiliary, copulative and other function verbs, e. g. You like it
here?
omission of the subject and auxiliary verb, e. g. Hear me?
omission of the subject and the copula-verb, e. g. Glad to see you again.