participial phrases: comma use

Commas follow introductory participial phrases, which are nonrestrictive and describe the subject of the main clause: Delayed by fog, the ferry docked at noon. The phrase Delayed by fog describes the ferry.

A restrictive participial phrase limits the meaning of the noun the phrase follows and takes no commas: The tenants living on the top floor lost power. The sentence means that only the tenants on the top floor lost power. A nonrestrictive participial phrase adds a detail about a noun already identified and takes commas: Our landlord, living two blocks away, arrived within minutes.

At the end of a sentence, a comma precedes a nonrestrictive participial phrase: The runner crossed the line, gasping for air. No comma precedes a restrictive participial phrase: The officer questioned the man standing by the door. The children ran out laughing.

An -ing phrase that serves as the subject of a sentence is a gerund phrase, not a participial phrase, and no comma separates a subject from its verb: Restoring the mural took three years. No comma follows a participial phrase that opens an inverted sentence, in which the verb precedes the subject: Taped to the door was a note from the landlord.

See also comma with introductory elements; comma with nonrestrictive clauses; absolute phrases: comma use; participle / participial phrase; dangling modifier; comma.