Interrupters

Use commas to set off expressions which interrupt the sentence. To set off an expression takes two commas unless the expression comes first or last in the sentence.

(1) Appositives with their modifiers are set off by commas. An appositive is a word – with or without modifiers – that follows a noun or pronoun and identifies or explains it.

A syndicated column by Bernard Silverman, the noted author, will appear in the Times-News, a local paper.

When an appositive is so closely related to the word it modifies that it appears to be part of that word, no comma is necessary. An appositive of this kind is called a restrictive appositive. Usually it is one word.

His cousin Arthur

The novel Windswept

Your friend Jean

William the Conqueror

The conjunction and

(2) Words used in direct address are set off by commas.

I don’t know, Alice, where your brother is.

Sam, please come here.

Your grades are disappointing, my boy.

(3) Parenthetical expressions are set off by commas. The following expressions are commonly used parenthetically: “I believe, I am sure, on the contrary, on the other hand, after all, incidentally, of course, in my opinion, for example, to tell the truth”, etc.

My father will, I am sure, let me have the car tonight.

The weight of the car, of course, determines the price of the license.

(4) Certain words when used at the beginning of a sentence or remark are followed by a comma. These words are “well, yes, no, why, oh”.

Yes, you were elected.

Oh, I wouldn’t be too sure about that.

Why, the entire argument is false!

(5) In dates and addresses every item after the first one is enclosed by commas.

Our sentimental idea was to hold a class reunion on June 18, 1966, at the old high school.

Address me at 222 Twin Oaks Road, Akron 3, Ohio, after the first of March.

Their son was born on Monday, May 1, 1949, in Baltimore, Maryland.

When only the month and day are given, no punctuation is necessary: It was on May 10 that we began work.

When the items are joined by a preposition, do not use commas.

He lived at 33 J Alain Street in Passaic, New Jersey.

(b) A nonrestrictive clause is set off by commas. A nonrestrictive clause is a subordinate clause which is not necessary to the meaning of the sentence, but merely adds an idea to the sentence.

NONRESTRICTIVE Joan Thomas, who was offered scholarships to three colleges, will go to Ml. Holyoke in September.

The basic meaning of this sentence is Joan Thomas will go to Mr.Holyoke in September. The subordinate clause does not affect this basic meaning, it merely adds an idea to the sentence. It is a nonrestrictive clause because it does not restrict in any way the word it modifies – Joan Thomas. Clauses which modify proper nouns are nearly always nonrestrictive. The opposite of a nonrestrictive clause is a restrictive clause.

RESTRICTIVE Joan Thomas is the only senior who won scholarships to three colleges.

Here the subordinate clause is necessary to the sentence, for without it the sentence would not say the same thing: Joan Thomas is the only senior. The subordinate clause restricts the meaning of senior – senior who won scholarships to three colleges.

(7) A nonrestrictive participial phrase is set off by commas. A participial phrase is a group of related words containing a participle. Like a nonrestrictive clause, a nonrestrictive participial phrase is set off by commas because it is not necessary to the meaning of the sentence.

NONRESTRICTIVE My little brother, playing in the street, was struck by a car.

RESTRICTIVE A child playing in the street may be struck by a car.

NONRESTRICTIVE Mrs. Hampton, frightened by the thunder, locked herself in a closet.

RESTRICTIVE People frightened by thunder

often try to hide.

NONRESTRICTIVE The crowd broke up suddenly, dispersing rapidly in all directions.

RESTRICTIVE I watched the crowd dispersing rapidly in all directions.