چگونگی استفاده صحیح از کاما یا ویرگول

.Use commas to indicate nonessential information If explanatory matter can be omitted without changing the general meaning of the sentence, it should be set off with commas. If the explanatory matter is essential to the meaning of the sentence, do not set it off with commas

.Correct: The novelist Don DeLillo seldom gives interviews

.Incorrect: The novelist, Don DeLillo, seldom gives interviews

Explanation: The identity of the specific novelist is essential to the meaning of the sentence. Otherwise, there is nothing to indicate which of the multitude of novelists is being referred to

.Correct: America’s first president, George Washington, served from 1789 to 1797

.Incorrect: America’s first president George Washington served from 1789 to 1797

Explanation: America has only one first president. Identifying him by name is not essential to the meaning of the sentence