The Elusive Comma (Part 4)

Commas in Adverbial Phrases and Clauses

When the main clause of a sentence is preceded by a phrase or a subordinate clause, you may use a comma to separate the phrase. (Sitting in the back, the group cheered wildly.) or (During the performance, the group cheered wildly.)

If the interruption to the flow of the sentence is slight, however, the comma may be omitted. The comma is usually omitted after short, introductory, adverbial phrases. (On Tuesday Bill was absent from class.)

An adverbial phrase or clause located between the subject and the verb should usually be set off by commas. (Bill, after picking up his assignment, went home.)

Commas should be used to set off interjections, transitional adverbs, and similar elements that affect a distinct break in the continuity of thought. (On the other hand, Bill may be right.) (Yes, Bill was right after all.)