Period ( . ) To indicate the end of a declarative sentence Example: Here is the place. To indicate that letters are used as abbreviations Example: Dr. Carle D. Reynolds To indicate decimal fractions Example: 16.34
Three Periods--Ellipses (…) To indicate that a portion of quoted matter is omitted Example: “To receive, obey, and pass on…”
Comma ( , ) To separate independent clauses joined by a conjuction Example: This is the street, but I don’t know the number of the house. Note: no comma is used unless each statement is independent. Example: You will police the area and maintain a fire watch. To separate parts of a series Example: Monday, Tuesday, and Wednesday To separate coordinate or “equal” adjectives in a series Example: a loud, sharp blast Note: Unless the adjectives modify the same noun in the same way, they are not in series and no comma is used. To test, check if the adjectives can be reversed. If not, no comma. Example: heavy woolen clothing
To separate introductory statements beginning with such words as when, while, since, if, because, until, although, and whenever (or other subordinate conjunctions) Example: When the rain was falling, there was very little wind. To set off introductory prepositional phrases (starting with on, in, at, to, by, for, of, through, etc.) Example: By the time she crawled into bed, she was too exhausted to sleep. Note: Short prepositional phrases (3 words or less) are not always followed by commas. Example: In Japan he served as platoon commander. To separate non-essential elements from the rest of the sentence. A non-essential element is a word or group of words that gives additional identifying information about someone or something already identified; it’s non-essential because the sentence is still clear without it. Examples: The President, who is the Commander-in-Chief of the armed forces, rates a salute. I visited Albany, the capital of the state of New York. Note: Commas are NOT placed around essential elements—those that limit meaning or give identifying information about someone or something not already identified. Example: The procedure that you are required to follow is explained in TM 5-250. To set off introductory phrases beginning with verb participles ending in –ing, -ed, -en, etc. Example: Having turned off the lathe, I stopped the motor. To set off such expressions as you, no, well, on the other hand, you might say, and of course, (such expressions are called interrupters) Example: He was, of course, the first person I saw. To set off such expressions as he said from direct quotations Example: “That decision,” he explained, “must be your own.” Note: No comma is used to separate such expressions from the rest of the sentence if the sentence is an indirect quotation (often introduced with the word that). Example: He explained that the decision must be my own. To separate contrasting elements Example: The wall is gray, not blue.
To prevent misreading Example: Undressing, the child ran into the bathroom. To set off the name of a person addressed Example: Frank, may I borrow your skill saw?
Semicolon ( ; ) To separate independent statements that are not joined by a coordinating conjunction (and, but, or, nor, for, yet, so) Example: Black is a mixture of all colors; white is the complete opposite. Note: If the independent statements are short, a comma may be used. Example: Horses sweat, men perspire. To separate independent statements when the second statement begins with such conjunctive adverbs or phrases like therefore, however, thus, otherwise, on the other hand, for example, in fact, that is, etc. Example: I submitted a request six months in advance; still, I did not receive a permit in time for the departure. To separate independent statements joined by conjunctions if such statements are long or they contain internal punctuation Example: Classic science fiction sagas include Star Trek, with Mr. Spock and...