This type of oppositional reduction concerns common countable nouns used in repetition groups. The nouns in repetition groups may be used either in the plural (‘featured’ form) or in the singular (‘unfeatured’ form):
There were trees and trees all around us. I lit cigarette after cigarette.
3) The nouns with homogenous number forms.
The number opposition here is not expressed formally but is revealed only lexically and syntactically in the context: e.g. Look! A sheep is eating grass. Look! The sheep are eating grass.
5.3. The Noun: Case
Case is the immanent morphological category of the noun manifested in the forms of noun declension and showing the relations of the nounal referent to other objects and phenomena. The category of case correlates with the objective category of possession.
This category is expressed in English by the opposition of the form in -'s [-z, -s, -iz], usually called the ‘genitive’ case , to the unfeatured form of the noun, usually called the ‘common’ case.
There can be singled out four approaches to the analysis of the problem of case of English nouns advanced at various times by different scholars:
1) the theory of positional cases (J. C. Nesfield, M. Deutschbein, M. Bryant, etc).
The unchangeable forms of the noun are differentiated as different cases on the basis of their functional positions in the sentence.
Thus, the English noun would distinguish
1. the inflexional genitive case,
2. the non-inflexional (purely positional cases):
Nominative: Rain falls. (subject to a verb)
Vocative: Are you coming, my friend? (address)
Dative: I gave John a penny. (indirect object to a verb)
Accusative: The man killed a rat. The earth is moistened by rain. (direct object, and also object to a preposition)
This view substitutes the functional characteristics of the part of the sentence for the morphological features of the word class.