Colons

You can get through most of your life without using a colon. Still, it’s a useful punctuation mark, and it can make a sentence clearer - especially when you’re introducing a long list.

Even though colons aren’t common in everyday writing, you should expect to see them on every ACT English test.

The good news is that colons follow a simple set of rules. If you remember these three, you’ll know when a colon is correct:

1. There must be an independent clause on the left side of a colon.

2. The independent clause must be a statement (not a question).

3. The words on the right side of the colon must specify the independent clause on the left.

That’s it.

If you apply these rules consistently, you’ll answer colon questions correctly.

Colon checklist

Here’s a simple way to check whether a colon is correct. Ask yourself these three questions:

1. Is there an independent clause on the left side of the colon?

2. If so, is that independent clause a statement (not a question)?

3. Do the words on the right side of the colon specify the words on the left side?

If the answer to even one question is no, you should not use a colon.

If the answer is yes to all three questions, a colon is appropriate.

Example

Use the checklist to decide whether the colon works in this sentence:

I bought three things at the store: bananas, apples, and Worcestershire sauce.

Checklist step #1: Is there an independent clause on the left side of the colon?

Checklist step #2: Is that independent clause a statement?

Checklist step #3: Do the words on the right side of the colon specify the words on the left side?

How not to use a colon

Here’s a common ACT trick with colons.

When the ACT wants to trap you, the problem is usually on the left side of the colon. The test will make the words before the colon a dependent clause (or otherwise incomplete), not an independent clause.

Example

Let’s look at an example.

At the store, I bought: bananas, apples and Worcestershire sauce.

Start with the first checklist question:

1. Is there an independent clause on the left side of the colon?

ACT tip

Look to the left of the colon first. If it isn’t a complete sentence, the colon is wrong. If it is a complete sentence, then the colon is at least a serious option.

The colon isn’t just for lists

On the ACT, you’ll often see a colon followed by a list (like the example below).

I have three favorite colors: blue, red, and green.

However, you can put more than just lists to the right of a colon. You still follow the same three rules (and they’re repeated below for convenience):

1. There must be an independent clause on the left side of a colon.

2. The independent clause must be a statement (not a question).

3. The right side of the colon must specify the independent clause.

Nothing in these rules says a colon can only introduce a list. On the ACT, you’ll sometimes see tougher questions that use a colon to introduce something other than a list.

Example

Here’s a non-list example of a colon:

I have a favorite color: blue.

It may look odd, but “odd” doesn’t mean incorrect. To decide whether the colon works, use the same three questions.

1. Is there an independent clause on the left side of the colon?

2. Is that independent clause a statement (not a question)?

3. Do the words on the right side of the colon specify the words on the left side?

Here’s another colon structure you may see on the ACT:

I have a favorite color: it is blue.

In this sentence, an independent clause appears after the colon (“it is blue”). This is still acceptable because it specifies what the left side states.

As long as you can answer “yes” to all three checklist questions, the colon is being used correctly.

ACT Examples

Here’s how you’re most likely to see colons tested on the ACT. For practice, try answering each question. One helpful strategy is to check the colon option first and eliminate it if it breaks the colon rules.

Example 1

While Batman is Michael Keaton’s most popular movie: my favorite Micheal Keaton movie is Beetlejuice.

A. NO CHANGE
B. movie my
C. movie; my
D. movie, my

Start with the colon option (choice A, NO CHANGE). Use the three colon questions. Is the colon correct?

Right now, don’t worry about finding the correct answer. To do that, you need to combine multiple punctuation rules, which will be covered in a later chapter.

If you want to test yourself anyway, try it here. Otherwise, skip to the next colon exercise.

While Batman is Michael Keaton’s most popular movie: my favorite Micheal Keaton movie is Beetlejuice.

A. NO CHANGE
B. movie my
C. movie; my
D. movie, my

Example 2

Let’s do one more.

Decide whether a colon should be used here. Again, focus on the answer option with a colon first, and apply the three colon questions.

While I enjoy reading, there are other things I’d rather be doing, hiking trails, going to the movies, or scrolling through TikTok.

A. NO CHANGE
B. doing; hiking
C. doing. Hiking
D. doing: hiking

Should you use a colon here?

You now have a reliable method for colon questions: check the left side first, then confirm that the right side specifies it.

Key points

Colons have three primary rules:

1. There must be an independent clause on the left side of a colon.

2. The independent clause must be a statement (not a question).

3. The right side of the colon must specify the independent clause.

You can use these rules on the ACT by asking the three colon questions:

1. Is there an independent clause on the left side of the colon?

2. If so, is that independent clause a statement (not a question)?

3. Do the words on the right side of the colon specify the words on the left side?