Last week we talked about the semicolon, which is used to separate two complete thoughts.
Today we will talk about the colon, which is used to separate a complete thought from a list.
A colon ( : ) announces the coming of a list.
I played three sports in high school: basketball, volleyball, and soccer.
Please put these things into the car: the rake, the hoe, and the yellow bucket.
I want you to buy the following items: cheddar cheese, milk, and oranges.
Notice that each sentence above includes a complete thought before the colon.
I played three sports in high school. Complete thought.
Put these things into the car. Complete thought.
I want you to buy the following items. Complete thought.
Put a colon after the complete thought and then list the items.
It’s important to know that we don’t always use a colon in a sentence with a list. Look at this example:
I played basketball, volleyball, and soccer in high school.
This new sentence gives the same information as the first example sentence above. Can you spot the difference?
This new sentence has a subject (I) and a verb (played) followed immediately by the list.
The very first example sentence in this post has a complete thought before the list starts, so we need a colon.
I played three sports in high school is a complete thought. Put a colon after that complete thought before you start the list. I played three sports in high school: basketball, volleyball, and soccer.
A colon also announces the coming of information.
Here is the most important thing to remember: you only get to live once.
You need to understand something: I’m doing this for your own good.
We have two choices here: rent a car or take the train.
Once again, each of these sentences has a complete thought before we add the colon and the extra information.
Look at the difference between these two sentences.
You need to understand something: I’m doing this for your own good.
You need to understand that I’m doing this for your own good.
The first sentence has a complete thought followed by a colon. The second sentence uses a subordinate clause word to join the two clauses.
The colon is a useful punctuation tool. Use a colon after a complete thought to announce the coming of a list. Also use a colon after a complete thought to announce the coming of extra information.