Sentence parts
Every sentence can be divided into certain components which are called parts of the sentence (Fig. 118).
Fig. 118
Parts of the sentence are usually classified into principal and secondary. The principal parts of the sentence are subject and the predicate. The subject is a person-modifier of the predicate. The predicate is a process-modifier of the subject-person. They constitute the backbone of the sentence. The secondary parts of the sentence are the object, the attribute, the adverbial modifier. The secondary parts of the sentence modify the principal parts or each other.The object is a substance-modifier of a processual part. The attribute is a quality-modifier of a substantive part. The adverbial is a quality-modifier of a processual part or the whole of the sentence.
Besides these two kinds of sentence components there are so-called independent elements, that is, elements standing outside the structure of the sentence, and therefore of lesser importance. The independent elements the parenthetical enclosure, the addressing enclosure, the interjectional enclosure. The parenthetical enclosure is a detached speaker-bound modifier of any sentence-part or the whole of the sentence. The addressing enclosure (address) is a substantive modifier of the destination of the sentence and hence, from its angle, a modifier of the sentence as a whole. The interjectional enclosure is a speaker-bound emotional modifier of the sentence.
Principle sentence parts subject
English sentence but the one-member and the imperative one must have a subject. The subject is one of the two principal parts of the sentence. The subject can be expressed in different ways (Fig. 119).
From the point of view of its grammatical value the subject may be either notional or formal (Fig. 120).
The notional subject denotes or (points out a person or a non-person, that is, various kinds of concrete things, substances, abstract notions or happening.
The formal subject neither denotes nor points out any person or non-person and is only a structural element of the sentence filling the position of the subject. Thus a formal subject functions only as a position-filler. In English there are two such position-fillers: it and there.
The formal subject expressed by it is found in two patterns of sentences: those with impersonal it and those with introductory it.
The formal subject it is impersonal when it is used in sentences describing various states of nature, things in general, characteristics of the environment, or denoting time, distance, other measurements.
The formal subject it is introductory (anticipatory) if it introduces the notional subject expressed by an infinitive, a gerund, an infinitive/gerundial phrase, a predicative complex, or a clause. The sentence thus contains two subjects: the formal (introductory) subject it and the notional subject, which follows the predicate.
The difference between the two structural types lies in that the pattern with the introductory subject accentuates the idea expressed by the notional subject, whereas the pattern without it accentuates the idea expressed in the predicate.
Sentences with a notional subject introduced by there express the existence or coming into existence of a person or non-person denoted by the subject. Such sentences may be called existential sentences or sentences of presentation. They are employed where the subject presents some new idea or the most important piece of information.
Fig. 119
Fig. 120