The Comma, Period, Semi-Colon, Colon, and Dash
- The Comma
- The Period (The Full Stop)
- The Semicolon
- Punctuating Quotations
Putting a comma before the "and" that indicates the last item in the series is optional. This comma is called the Oxford comma or the serial comma. Note that the use of the serial comma is recommended in The Publication Manual of the American Psychological Association (7th ed.).
Put commas around an expression such as however, moreover, therefore, of course, I think, indeed, etc., that interrupts a sentence midway through. These expressions are considered extraneous to primary meaning of the sentence.
Put commas around non-essential modifiers, also known as non-restrictive modifiers. This rule is related to rule 4 above, but rather than referring to expressions of one or two words, it deals with longer material. In a sentence, a non-essential or non-restrictive modifier may be interesting, but the primary meaning of the sentence would be clear without it.
This sentence sounds like all women were accused. The modifier "who chose to wear bloomers" is essential because it tells us which women the sentence is about. It is an essential or non-restrictive modifier and it is not set off from the rest of the sentence with commas.
This rarely, if ever, happens in academic writing, so this rule is more for your information than anything else. It might occur in a formal letter or email when you want to directly address the person to whom you are writing.
- End of a sentence
- Period after an abbreviation
- Use a period after an abbreviation: when the abbreviation does not end with the last letter of the word: Jan. Nov. Mon. Weds.
- You do not need a period after an abbreviation when the abbreviation ends with the last letter of the word. So: Dr St (for street or saint) Ave
- Between two independent clauses: Use a semicolon between two independent clauses when you want to join them together and make a compound sentence. Learn more about compound sentences.
- Between Items in a Lengthy Series
- An Individual Item or Series of Items
- An Idea Contained in the Preceding Clause
- Sudden Shift in Direction: Sometimes, you may have a phrase which contradicts or negates what has gone before, and a dash is a useful way of drawing the reader's attention to that contradiction.
- Question or exclamation in the middle of a sentence
If you use attributory words, words that identify the speaker or the writer and a verb of saying (says, writes, observes, notes etc), use commas to set off these words, whether they appear before, after, or between parts of the quotation.
Hedley Bull is quite clear on this point: "We are accustomed, in the modern world, to contrast war between states with peace between states, but the historical alternative to war between states was more ubiquitous violence."