Comma it is preceded by a semicolon and followed by a comma. Using commas to offset certain adverbs is optional, including "then", "so", "yet", "instead", and "too" (meaning "also"). Commas are often used to enclose parenthetical words and phrases within a sentence (i.e., information that is not essential to the meaning of the sentence). Such phrases are both preceded and followed by a comma, unless that would result in a doubling of punctuation marks or the parenthetical is at the start or end of the sentence. The following are examples of types of parenthetical phrases: A comma is used to separate
That is often omitted when used to introduce a subordinate clause—""He told me that it is a good read."" could just as easily be ""He told me it is a good read."" Historically, "that" usually followed a comma: "He told me, that it is a good read." Middle Modern English grammarian Joseph Robertson recommended in "On Punctuation" that a comma be used with a conjunction. However, if the subordinate, conjunctional ellipse, null complement, or syntactic pleonasm of "that" is punctuated with a comma, then, in the English grammar, stylistically speaking, it is a comma splice, especially in formal writing. Instead, a