Q: I’m studying English in Japan, and I’m confused by the use of prepositional phrases as subjects, as in this example: “Across the field is the nearest way to the lake.” Is this a common usage? Can prepositional phrases be objects too?
A: A prepositional phrase can be the subject, object, or complement of a verb. This is a common construction in English, and often the verb is a form of “be,” as in your example. Here are a few more illustrations.
As subject: “Over the mantle is a good place for the mirror” … “From five to seven would be the best time.”
As object: “He directed between 50 and 60 movies” … “The project will take over a week.”
As complement: “A good place for the mirror is over the mantle” … “The best time would be from five to seven.”
(With a linking verb like “be,” a subject complement occupies the position of the object.)
The Cambridge Grammar of the English Language cites these examples, with “spent” as the verb: “Over a year was spent on this problem” (subject) … “I spent over a year here” (object).
Prepositional phrases can be modifiers, too. So they can act as adverbs (“Puffin lies on the bed” … “In the afternoon, Puffin naps”) or as adjectives (“The cat on the bed is Puffin” … “Naps in the afternoon are her favorite”).
In fact, a prepositional phrase “is by far the commonest type of postmodification in English,” according to A Comprehensive Grammar of the English Language, by Randolph Quirk et al.
The authors give many examples of such modifiers following nouns, including “the car outside the station,” “the road to Lincoln,” “this book on grammar,” “passengers on board the ship,” “action in case of fire,” “the house beyond the church,” and “two years before the war.”
In addition, the authors explain, prepositional phrases can complement a verb (“We were looking at his awful paintings“) or an adjective (“I’m sorry for his parents“).