ACT and SAT Punctuation 101: Combining Sentences

Bonus Material: PrepMaven’s Combining Sentences Worksheet with FREE Practice Questions

Most punctuation questions on the SAT/ACT test your ability to identify complete and incomplete sentences

Once you’re fluent in distinguishing these two types of sentences, you’re all set to learn about the punctuation needed for combining them!

Those are the rules we’ll be discussing in this post. Plus, we walk you through guided examples using official practice test questions. 

We also give you access to our Combining Sentences worksheet, which includes additional practice questions and explanations.

Grab this below before we get started.

Here’s what we cover:


Complete & Incomplete Sentences in a Nutshell

We discuss the difference between complete and incomplete sentences at great length in our Complete and Incomplete Sentences post

For now, here’s a helpful chart for breaking down the difference between these two types of sentences:

Complete Sentences Incomplete Sentences

Have:

  • subject
  • verb
  • full expression of an idea

Don’t have:

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

Identifying whether an idea is complete or incomplete on the SAT or ACT can be challenging, which is why we encourage students to practice honing this skill before they learn and memorize punctuation rules. 

When you encounter an ACT or SAT punctuation question, it’s always important to read for full context. Doing so can help you determine if you are dealing with a combining sentences question or if you’ll have to apply your knowledge of comma rules.

Giving the answer choices a quick scan can also clue you into what type of punctuation question you’re dealing with.

For example, if you see a bunch of commas at different places in your answers, that’s a good sign it’s a comma rules question! If you see a mix of colons, semicolons, long dashes, and commas, this is probably a combining sentences question.

Here is our strategy for approaching punctuation questions that involve combining sentences (incomplete, complete, or both):

  1. Read the full context
  2. Focus on one idea or sentence at a time
  3. Look for the 3 components of a complete sentence
  4. Write down whether it’s incomplete or complete

What we’ll discuss next is what to do after you’ve completed step 4 of this strategy. Now it’s time to talk punctuation rules!


ACT and SAT Punctuation Rule #1: Combining Complete Sentences

Let’s say that you’ve identified two complete sentences in an ACT or SAT punctuation question, as in this example here:

It’s not that people are disinterested in

climate change, many would argue that

citizens are very interested in the planet’s

gradual warming.

A) NO CHANGE

B) change; many

C) change many

D) change

“It’s not that people are disinterested in climate change” is a complete sentence, as it has a subject (“it”), a verb (“is”), and a full expression of an idea. The same goes for the second sentence, “many would argue that citizens are very interested in the planet’s gradual warming,” which has a subject (“many”), verb phrase (“would argue”), and full expression of an idea.

At this point, it’s time to choose the punctuation that is appropriate for combining 2 complete sentences.

When combining 2 complete sentences, you can ONLY use one of the following:

  • semicolon
  • period
  • comma + FANBOYS conjunction (for, and, nor, but, or, yet, so)

On the SAT or ACT, you will never have to choose between one of these three options (i.e., a semicolon versus a period).

In fact, if you see a semicolon and a period in the answer choices–and nothing else differs between those options–you can automatically cross those choices off, as you can’t have two right answers.

In the example above, the only permissible answer choice is B, which uses a semicolon to join 2 complete ideas. With this choice, this is how the new sentence would read:

It’s not that people are disinterested in climate change; many would argue that citizens are very interested in the planet’s gradual warming.

You could also write this sentence using a period or a comma + FANBOYS conjunction, as in these two examples:

Period

It’s not that people are disinterested in climate change. Many would argue that citizens are very interested in the planet’s gradual warming.

Comma + FANBOYS conjunction

It’s not that people are disinterested in climate change, for many would argue that citizens are very interested in the planet’s gradual warming.

Two More Tips About Semicolons

Remember: semicolons only like to hang out between 2 complete sentences. Yet, occasionally, they can come before a transition word like “however,” “nonetheless,” or “moreover.”

This is perfectly acceptable, as long as that transition word has a comma after it. We’ll use the same example from above to show this rule in action:

It’s not that people are disinterested in climate change; indeed, many would argue that citizens are very interested in the planet’s gradual warming.

Notice how the semicolon in this sentence comes before a transition word, “indeed,” which is followed appropriately by a comma.

Additionally, FANBOYS conjunctions (for, and, nor, but, or, yet, so) never follow a semicolon. If you see this as an option in an answer choice, you can always cross it off!


ACT and SAT Punctuation Rule #2: Combining Complete & Incomplete Sentences

What happens when you need to combine a complete and incomplete sentence, as in this example here?

In light of the fact that women are still

earning less than men in the workplace,

for example: equity consulting companies

are likely to prove their value in years to

come.

A) NO CHANGE

B) for example; equity

C) for example, equity

D) for example. Equity

“In light of the fact that women are still earning less than men in the workplace, for example” is an incomplete sentence, as it has a subject (“women”) and a verb phrase (“are still earning”) but lacks a complete expression of an idea. “Equity consulting companies are likely to prove their value in years to come” is a complete sentence, as it has a subject (“companies”), verb (“are”), and full expression of an idea.

There is only 1 real option for combining a complete sentence and incomplete sentence:

  • a single comma

Now, if the incomplete sentence is in fact just a phrase (as opposed to a clause, which has a subject and a verb), this could mean we’re in the territory of either comma rules or colon rules.

For example, if your incomplete sentence is a transition phrase, like “on the other hand,” chances are, it’s time to apply some comma rules! 

Let’s apply this rule to the example above. The only answer choice that has a single comma as a solution is C. The corrected sentence would thus read as follows:

In light of the fact that women are still earning less than men in the workplace, for example, equity consulting companies are likely to prove their value in years to come.

Notice how the answer choices have a period and a semicolon in them–you can automatically cross these off as you can’t have 2 correct answers!

Get a jumpstart on applying these rules in practice with our Combining Sentences worksheet, which includes practice questions, guided examples, and more.


Guided Examples

Let’s apply these rules to 2 sample questions, both taken from official SAT and ACT practice tests. As a refresh, this is our full strategy for approaching a combining sentences question on the SAT or ACT:

  1. Read the full context
  2. Focus on one idea or sentence at a time
  3. Look for the 3 components of a complete sentence
  4. Write down whether it’s incomplete or complete
  5. Identify appropriate punctuation and eliminate rule-breakers
Joining 2 Complete Sentences Joining 1 Incomplete + 1 Complete Sentence 
  • semicolon
  • period
  • comma + FANBOYS conjunction
  • a single comma

Example 1: SAT Punctuation Question

ACT and SAT Punctuation: Combining Sentences Example
Source: CollegeBoard Official SAT Practice Test 1

1. Read the full context

It’s always important to read more than just the underlined portion of a question on ACT English or SAT Writing & Language. The full idea here establishes a cause and effect relationship: people should continue to produce Greek yogurt safely because of its health benefits.

Context also tells us that there are 2 sentences to be joined here.

2. Focus on one idea or sentence at a time

We’ll focus on these 2 sentences individually: “because consumers reap the nutritional benefits of Greek yogurt and support those who make and sell it” and “farmers and businesses should continue finding safe and effective methods of producing the food”.

3. Look for the 3 components of a complete sentence

The 3 components of a complete sentence are a verb, subject, and full expression of an idea.

The first sentence (“because…it”) has a subject (“consumers”) and a verb (“reap”) but lacks a full expression of an idea due to the word “because” at the beginning.

The second sentence (“farmers…food”) has a subject (“farmers and businesses”), verb (“should continue”), and complete expression of an idea. 

4. Write down whether it’s incomplete or complete

The sentence starting with “because” is incomplete. The one beginning with “farmers” is complete.

5. Identify appropriate punctuation and eliminate rule-breakers

We can only use a single comma to join an incomplete sentence to a complete sentence. We can eliminate answer D.

The word “because” at the start of the first sentence means that the words “therefore” and “so” would be redundant and unneeded, so we can cross off answer choices C and A. This leaves us with answer B.

Here’s how our corrected sentence would read:

Because consumers reap the nutritional benefits of Greek yogurt and support those who make and sell it, farmers and businesses should continue finding safe and effective methods of producing the food.

Example 2: ACT Punctuation Question

ACT and SAT Punctuation Rules: Combining Sentences
Source: ACT.org Official ACT Practice Test #1

 

 

 

 

 

 

 

 

1. Read the full context

This question is a bit more challenging, just because there’s so much more happening in context. The key is to read carefully, however, and try not to get sidetracked by all of those long dashes.

Context tells us that certain “untruths” aren’t that important given that the autobiography in question doesn’t focus on Mother Jones’ life.

2. Focus on one idea or sentence at a time

We’ll focus on these 2 sentences individually: “These untruths ultimately matter very little” and “the autobiography isn’t about the life of Mary Harris Jones.”

3. Look for the 3 components of a complete sentence

The 3 components of a complete sentence are a verb, subject, and full expression of an idea.

The first sentence has a subject (“untruths”), verb (“matter”), and full expression of an idea. So does the second, with its subject (“autobiography”), verb (“isn’t”), and full expression of an idea.

4. Write down whether it’s incomplete or complete

Both sentences are complete.

5. Identify appropriate punctuation and eliminate rule-breakers

We can use any of the following to join 2 complete sentences:

  • semicolon
  • period
  • comma + FANBOYS conjunction

This means we can cross off every answer except F! Remember that we can’t have a FANBOYS conjunction after a semicolon or a period, which is why we can eliminate G and H, and a single comma can only join an incomplete sentence to a complete sentence.


Download PrepMaven’s Combining Sentences Worksheet

Now that you know the essential rules for combining sentences on the ACT and SAT, it’s time for some test-like practice!

Apply your new knowledge to the FREE practice questions in our Combining Sentences worksheet.

Combining Sentences_SAT and ACT Punctuation

With this worksheet, you’ll get: 

  • A recap of what we discussed in this post
  • Guided examples of punctuation questions from official practice tests
  • 10 practice questions with detailed answers/explanations 


Kate_Princeton Tutoring_AuthorBio Kate M.

Kate is a graduate of Princeton University (B.A. in English Literature and Interdisciplinary Humanities) and Boston University (M.F.A in Creative Writing). 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.