; The semi-colon
There are only two uses for the semi-colon.
1. To separate two sentences that are closely related or which reflect each other:
We all enjoy our flat; it has a great atmosphere.
There are the benefits of sharing; there are also the disadvantages of the lack of privacy.
2. To separate listed items that are particularly long or have commas within the items:
There are many things on my to-do list. I need to run down to the bank to cash my cheque before 4:30pm; pick up my clothes from the drycleaner, unless they haven't finished cleaning them yet; and take the car to a carwash.
How to ensure you are using the semi-colon correctly
If you are separating two sentences (the first use) you should be able to replace the semi-colon with a full stop:
We all enjoy our flat. And it has a great atmosphere.
We all enjoy our flat. It has a great atmosphere.
Note: semi-colons are often the fastest solution to a comma splice, because they can be used between two full sentences without needing a connecting word ('and', 'so', 'but', etc.). See the section on commas for more on comma splices.
: The colon
The colon is used to introduce something. That something can be a single word or it can be a full sentence, but whatever comes after the colon should explain, illustrate, or resolve what comes before the colon:
If you don't plan your assignment, you're setting yourself up for one thing: failure.
Every author needs to identify with their characters: they need to care about them like children.
When used in this way, the words before the colon should form a full sentence (i.e., they should be able to stand independently).
I will bring: chips, dip, and beer.
I will bring the following items: chips, dip, and beer.
If the words before the colon do not form a complete sentence, remove the colon:
I will bring chips, dip, and beer.
Colons are often used to introduce quotations or lists, or to separate a title and a subtitle:
The theory was developed by Kozlov (1999, p. 22): “The optimum use of the available resources is best described using an adapted form of Disbursement Theory.”
You need only a few basic ingredients to make scones: flour, baking powder, butter, and milk.
Cell and molecular biology: Concepts and experiments
Note: colons can be used to correct a comma splice, but only if the first sentence introduces the second sentence. See the section on commas for more on comma splices.
( ) The bracket
Brackets, also known as parentheses, are used to mark off information that is relevant, but is not crucial to the sentence:
My mother worked for a legal firm (which has since been sold) on the corner of Ash Street.
The landlord is always coming around (to check up, we suspect), so we are looking for another flat.
Note: You can also mark off information using dashes (see below) or commas.
– The dash
Dashes are used to mark off information which is relevant, but is not crucial to the sentence. It gives more emphasis to the extra information, but can make your writing choppy if you use it too much.
We take turns – at least we try to – at shopping and cooking.
We all got there eventually – and then it was time to leave.
If you add information in the middle of a sentence, you must have dashes on both sides.
Note: the dash is longer than the hyphen (see below), and in academic writing usually has a space on each side.
‐ The hyphen
The hyphen is used to connect two words where there might otherwise be confusion:
A Dutch-cheese importer is anyone who imports Dutch cheese; a Dutch cheese importer is a Dutch person who imports any sort of cheese.
A small-arms retailer will sell you a hand-gun (small arms); a small arms retailer is a short (small) person who sells a wide range of guns (arms).
Note: the hyphen is shorter than the dash (see above), and in academic writing has no spaces on either side.
… The ellipsis
The ellipsis indicates that something has been left out of a quotation deliberately, to make it easier to read or to highlight only the main points. Under most referencing systems ellipses are only used when something has been omitted from the middle of a quotation, not the start or end:
According to Rice (1991, p. 17), “management … is a major component” of any good business.
Note: sometimes you will see an ellipsis used at the end of a sentence to indicate ‘trailing off’. This is inappropriate for academic writing.