The Importance of the Oxford Comma in Writing

Appositives add extra information about a noun, and when that information is not essential, it should be set off with commas. Example: My brother, a firefighter, lives in Texas. The appositive “a firefighter” gives us extra information about “my brother,” but the sentence still makes sense without it. That’s why we use commas. However: Author Alan Gratz wrote Refugee. Here, “Alan Gratz” identifies which author, so no commas are needed. Learning when to use appositives can make your writing clear

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