SAT and ACT Punctuation: Colons and Long Dashes

Bonus Material: PrepMaven’s Colons and Long Dashes Worksheet with FREE Practice Questions

ACT English and SAT Writing & Language test punctuation rules more than any other grammar concept. These rules include colons and long dashes. 

While colons appear relatively frequently on both tests, long dashes are a bit rare. 

However, both colons and long dashes share some common ground, which is why we’re discussing them in one post.

Before you keep reading, we recommend that you check out these posts first (if you haven’t done so already), as we reference their concepts quite a bit in this article:

We also encourage you to download our free Colons and Long Dashes worksheet so you’ll have practice questions on hand before diving in. Grab it below.

Here is what we’ll cover in this post on colons and long dashes:

SAT and ACT Punctuation: Colons and Long Dashes

Where can you expect to apply your knowledge of colons and long dashes on the SAT or ACT?

As a reminder, both exams directly test students’ proficiency in English grammar concepts on the following 2 sections:

  • SAT Writing & Language
  • ACT English

Punctuation is, by far, the most commonly tested English grammar concept on both of these sections. Here’s what you can expect to see in terms of the number of SAT and ACT punctuation questions on either test, based on our analysis of officially released practice tests:

Punctuation Questions on the ACT Punctuation Questions on the SAT
12-16 5-7

Remember that the ACT English section is longer than SAT Writing & Language, with 75 questions (as opposed to 44 questions). Get insight into the way these tests are structured in our ACT Format and The 5 SAT Sections: What You Need to Know posts.

We do want to stress that your knowledge of English conventions can be helpful on one other section of both tests: the Essay portion.

While the SAT/ACT Essay is optional, if you do decide to take it, essay graders will be giving a general assessment of your grammar skills on the page. Demonstrating proper usage of colons, long dashes, apostrophes, semicolons, and commas can only help you get closer to a competitive essay score!

If you’re reading this post, you’ve likely already settled on one of these two college entrance exams.

However, if you’re still on the fence about whether or not to take the SAT or the ACT, ask yourself these 5 questions. Remember that all U.S. colleges and universities accept either ACT or SAT scores from applicants, and have no “preference” for one standardized test over another. (There are a few test-optional schools, though.)

Colons in a Nutshell

As we mentioned in the introduction to this post, we encourage our students to read these articles first before proceeding with this section about colon rules:

Why do we recommend this? Well, colon usage on the SAT and ACT basically boils down to your ability to identify complete and incomplete sentences.

For a quick recap, here’s a visual that breaks down the difference between an incomplete sentence and a complete one:

Complete Sentences Incomplete Sentences


  • subject
  • verb
  • full expression of an idea

Don’t have:

  • subject
  • verb
  • and/or full expression of an idea

The #1 Colon Rule You MUST Know

When it comes to using a colon properly, it’s particularly important to know what makes up a complete sentence. That’s because of this one important colon rule:

The sentence that precedes a colon must be complete.

It doesn’t matter what comes after a colon, really–incomplete sentence, complete sentence, a phrase, a single word. All that matters is that the sentence that comes before the colon is complete. That’s it!

Other Colon Considerations

There are 2 other things to keep in mind when it comes to colon rules.

We want to point out that most students are likely familiar with this definition of a colon, as per their English classes:

A colon comes before a list, explanation, or elaboration.

This is definitely true. But when it comes to SAT and ACT punctuation questions, students only have to be on the lookout for a complete sentence to the left of that colon.

What’s more, some students wonder if they’ll have to choose between a colon, a semicolon, or a period on ACT English or SAT Writing & Language. But here’s the deal:

You’ll never have to choose between a colon, semicolon, or period on SAT Writing & Language or ACT English if all are used correctly in the answer choices.

(If used properly, these differ only in terms of style and/or emphasis, which is not tested on the SAT or ACT.)

That means that there are essentially 3 things to keep in mind when it comes to colons. (Hint: we recommend writing these down on flashcards!)

  1. A colon must come after a complete sentence.
  2. It typically precedes a list, explanation, or elaboration (but this isn’t directly tested).
  3. You won’t ever have to choose between a colon, semicolon, or period if all are used correctly.


Here are 3 example sentences that demonstrate proper colon usage:

The treasure trove contained a startling array of both riches and detritus: old bank receipts, rare gems, crumbling seashells, a stack of manuscripts, pendants and bracelets, and even a gold coin.

Based on these facts, some might conclude that Shakespeare was, in fact, the opposite of who he was allegedly acclaimed to be: not an original writer but, rather, a clever plagiarist.

Eighteenth-century female painters were, to no one’s surprise, forbidden from painting many “scandalous subjects:” chief among these subjects was the male figure.

Notice how all three of these have a complete sentence before the colon, which contains a subject, a verb, and the full expression of an idea.

Colons: Guided Example

We’ll apply these colon rules now to a sample SAT punctuation question from an officially released SAT practice test (#3).

Guided Example: SAT Punctuation Question

SAT/ACT Punctuation: Colons Example

It’s always important to read the full context of any question you encounter on ACT English or SAT Writing & Language. The full sentence that contains the underlined portion for question #29 is as follows:

Take Bartlett pears, for instance, unless they are treated with exactly the right amount of 1-MCP at exactly the right time, they will remain hard and green until they rot…

This is a long sentence! However, by skimming our answer choices, we can see that the question wants us to focus on only one portion of this sentence: namely, the punctuation surrounding “for instance.”

Critical thinkers might notice here that “for instance” is a transition phrase. We know from our discussion of comma rules that transition phrases require 1-2 commas, depending on where they appear in the sentence. At the very least, we’ll want a comma before the “for.” This helps us eliminate answers C and D.

How do we decide between A and B? Let’s apply our knowledge of complete and incomplete sentences. “Take Bartlett pears, for instance” is a complete sentence. So is “unless they are treated…them again.” We know from the rules of Combining Sentences that we can’t combine 2 complete sentences with just a comma, so B is our answer.

Notice how this question required knowledge of all of the following rules:

  • Using a comma with transition phrases/words
  • Comma splices (you can’t combine 2 complete sentences with just a comma)
  • You must have a complete sentence before a colon

This is very typical of SAT and ACT punctuation questions, which often test more than one rule in a single question!

Your can apply your knowledge of colons right now by working through the practice questions in our free Colons and Long Dashes worksheet.

Long Dashes in a Nutshell

The first thing to know about long dashes is that they are not the same as hyphens! We use hyphens to join two words together, as in the following examples:

  • star-crossed lovers
  • bad-tempered instructor
  • a custom-built home

Long dashes have a very different purpose. We use long dashes (–) on only 2 occasions:

  1. To indicate a change in tone, an elaboration, or new thought (single long dash)
  2. Offset additional, explanatory, and/or descriptive information (two long dashes)

Let’s talk about Rule #1 first, as it can be the most challenging for students to grasp.

Long Dashes: Rule #1

It is possible (and yes, we’ve seen this rule tested on both exams) to use a single long dash to indicate a change in tone or new thought. In this way, a single long dash functions exactly like a colon.

And the rule with colons? A complete sentence must come before a colon. The same applies to the single long dash: it must be preceded by a complete sentence!

Here’s an example of a single long dash functioning much like a colon. Notice how the sentence that comes before the long dash is a complete sentence and that what comes after the long dash is a new thought or elaboration.

That’s just it–we don’t know all of the answers to the questions of the universe.

To test for proper use of the single long dash, see if you can replace it with a colon. If you can (i.e., if that sentence on the left of the punctuation is complete), then the single long dash is permissible. This is the similarity between long dashes and colons that we referenced earlier on in this post!

Long Dashes: Rule #2

You can use two long dashes to separate additional information from the rest of the sentence, much like a set of parentheses or a pair of commas.

This is why knowledge of comma rules can be helpful for comprehending long dash usage: one of the essential comma rules tested on the SAT and ACT involves using two commas to separate descriptive, non-essential information from the rest of the sentence.

Two long dashes function in exactly the same way! Take a look at the following sentence, written once with long dashes and a second time with commas:

The pier to the left of the canoe house–reputed to be haunted by a restless ghost–is a popular destination for tourists.

The pier to the left of the canoe house, reputed to be haunted by a restless ghost, is a popular destination for tourists.

There is no grammatical difference between these two sentences! However, on the SAT and ACT, you will never have to choose between two long dashes and two commas if both options utilize correct punctuation.

Pro tip: Always hunt for a long dash in the non-underlined portion of a passage if you see a long dash in one of your answer choices. This could be a good sign that you’re dealing with this second rule.

Download Our Colons and Long Dashes Worksheet

Remember: colons and long dashes are often tested in combination with other punctuation rules on the SAT and ACT.

It’s thus critical to feel confident in applying these rules in practice. You can do this right now with our free Colons and Long Dashes worksheet.

Colons and Long Dashes on the SAT/ACT

With this worksheet, you’ll get: 

  • A recap of the rules we discussed in this post
  • Guided examples of questions from official practice tests
  • Practice questions with detailed answers/explanations 

Kate_Princeton Tutoring_AuthorBio Kate

Kate is a graduate of Princeton University. Over the last decade, Kate has successfully mentored hundreds of students in all aspects of the college admissions process, including the SAT, ACT, and college application essay.