Colons. How and when to use them (part 1)

Colons are used:

• To extend a sentence, to expand on something previously mentioned in the sentence (e.g., I'm looking for just one personal trait: discipline.)

• After an introduction (e.g., I've seen the following: ants, a cockroach, and a rat. )

• In references, times, and titles (e.g., Read Genesis 1:1 before 07:30. )

• With quotations (e.g., He said: "Curiosity killed the cat, but for a while I was a suspect." )

Using Colons

Colons (:) are quite versatile. It is worth learning how to use them — especially how colons allow you to expand on an idea previously mentioned in the sentence. (If you can master this idea, you'll have a useful tool in your writing armoury.)

Using Colons to Extend a Sentence

Think of a colon (:) as the language version of an equals sign (=) in mathematics. The information on the left of the colon equals the information on the right. Usually, the information on the right is an expansion of whatever is mentioned on the left. For example:

• He blamed his divorce on one thing: beer.

• (one thing = beer)

• There are two reasons why I don't believe the alibi: there is no visa in his passport, and he is petrified of flying.

• (two reasons = the visa idea and the flying idea)

Sometimes, the ideas either side of the "equals sign" are a little harder to marry up. For example:

• I have made an important discovery: alcohol, taken in sufficient quantities, produces all the effects of intoxication. (Oscar Wilde)

• (discovery = the alcohol idea)

You cannot introduce a new idea with a colon. For example:

• I have made an important discovery: it's my first important discovery this year.