They are one-member sentences with a noun, a prepositional noun-phrase, or an adverb. They are often used in emotive prose in descriptions of nature, interior, appearance, etc. to produce an effect of a detailed but laconic picture foregrounding its main components, and as the background of dialogue, mentioning the emotions, attitudes, moods of the characters. Nominative sentences may produce the effect of increasing the dynamism of narration and acquainting the reader with the place or background of action.