Conventions of Composition Rule 28
Rule: If an nonrestrictive (unnecessary to the meaning of the sentence) appositive has more than one word, separate it from the rest of the sentence with a pair of commas. If an appositive is restrictive (necessary for telling which particular person or thing or which kind of person or thing) or one word, you need not separate it with commas.
Correct: George Washington, our first president, died in 1799.
Correct: In Shakespeare’s play Julius Caesar the hero is Brutus.
Correct: The Civil War began in the year 1861.
Practice deciding if or where these appositives need commas around them:
My brother Humperdinck might rule the all of Florin someday.
Her car the Ford F-150 with huge tires is in the shop.
Preps find taking the four Grammar Gateways best four classes of the year both challenging and enjoyable.
Resources for further explanation of punctuating appositives:
Purdue OWL's Appositives
Grammar Book's Commas with Appositives