Can you recognize a sentence when you see one?
Most people will automatically answer that they can. But correct sentence structure is one of the most commonly-tested grammatical concepts on the SAT Writing section.
What does it take to make a sentence complete? How can you recognize a fragment or a run-on? Read on to figure out how the SAT manages to trick so many students with this seemingly easy concept.
In this guide I am going to show you:
- What constitutes a complete sentence
- How prepositional phrases, appositives and non-essential clauses can make sentences more difficult to understand
- How to recognize and fix fragments
- How to recognize and fix run-on sentences
- Strategies to attack these kinds of questions
- Examples of this kind of question from the SAT
To start, take a look at the following. Some of these are correct sentences. Others are fragments or run-ons. Can you tell which are which? Do you understand why the incorrect sentences are incorrect?
- Rebecca, the chef, struggles to find fresh mozzarella in the stores.
- Rebecca, who was a fantastic chef skilled in making pasta and pizzas.
- After working in a restaurant for ten years, Rebecca opened her own Italian cafe, it was called “Mi Piace.”
- Rebecca, who was skilled in making pasta, did not enjoy eating it.
- Although Rebecca was very skilled in making pasta, and ate it all the time.
- Her friends delighting in her pizzas and baked goods.
- She loved pizza.
- Because she showed a talent for cooking from a young age, Rebecca, who had a closet full of children’s cookbooks.
- Rebecca ate a lot of pizza, soon she started cooking it, too.
Answers: 1. Sentence; 2. Fragment; 3. Run-on; 4. Sentence; 5. Fragment; 6. Fragment; 7. Sentence; 8. Fragment; 9. Run-on
How did you do? As you can see, it can be more difficult than you might think to correctly identify a sentence every time - and even more so to understand why an incorrect sentence is not right. Keep reading and we will cover exactly what a sentence needs to be correct.
What Is a Sentence?
Sentences can be short or long, simple or complex. In order to have a correct, complete sentence, you really only need two things: a subject, and a verb that is conjugated to match the subject.
A subject and a correctly conjugated verb together, along with anything else that goes with them, form an independent clause. Don't worry, you don't need to know that term for the SAT! But it will be useful as we move forward for understanding sentences. An independent clause can stand on its own as a complete sentence because it makes sense as it is and expresses a complete thought.
For example, all of the following are independent clauses:
The girl runs.
The girl with bows in her hair runs.
The young girl with bows in her hair runs through the village square.
Each of these has a subject, a correctly conjugated verb, and makes sense without any additional information. The subject in each of these sentences is "girl". The verb, "runs", is correctly conjugated in the third person singular to match the subject. If you wanted to, you could get rid of all the additional words in the second and third sentences above, and they would still make sense.
There is one situation in which you can have a complete sentence, but you will not be able to pick out the subject and the verb. This is with commands. Commands always have an understood subject of "you", which means that it does not need to be written.
Run! Speak! Run down the street and speak to your grandmother!
Fortunately, the SAT does not test this concept very often, but it's important to understand just in case it does come up.
So now you know the basics of a simple sentence!
Sentences can have more than just one independent clause, however — and this is where things can get tricky. They can have a second independent clause, or the independent clause can be attached to a dependent clause.
Sentences with More than One Independent Clause
Sometimes, sentences can have more than one independent clause. If this is the case, you have to make sure that they are joined together correctly. If they are not, they are considered run-on sentences. We will talk more about how to recognize run-ons, but let's first focus on how things are done correctly.
There are a few different ways that you can correctly join two independent clauses together to make one compound sentence.
#1: Don't join them at all!
This may be the easiest solution at times. You do not have to join the clauses together. Keep them separated by a period.
Julia and Louise both like to eat pizza. They both love pepperoni.
#2: Join the sentences with a comma followed by a coordinating conjunction.
Coordinating conjunctions can be remembered by the acronym FANBOYS:
Julia and Louise both like to eat pizza, for they both love pepperoni.
#3: Join the independent clauses with a semicolon.
A semicolon on its own basically functions exactly the same way a period does. You can join the two clauses with a semicolon and nothing else.
Julia and Louise both like to eat pizza; they both love pepperoni.
#4: Join the sentences with a semicolon and a conjunctive adverb.
Some of the most common conjunctive adverbs include however, nevertheless, therefore, moreover, and consequently.
Different conjunctive adverbs show different relationships. For example, "however" and "nevertheless" imply a contrast, so use these if one sentence gives information that somehow contrasts the previous one. "Therefore" and "consequently" imply a cause-and-effect relationship. Use these when one sentence is a result of something the happened in the previous sentence. "Moreover" is used to indicate expand on the information given in the first sentence.
Julia and Louise both like to eat pizza; moreover, they both love pepperoni.
Note that conjunctive adverbs can come after either a semicolon or a period, but they must be followed by a comma.
#5: Turn one of the independent clauses into a dependent (or subordinate) clause.
We will go into dependent clauses in more detail in a moment, but for now, this is what this solution would look like:
Since they love pepperoni, both Julia and Louise like to eat pizza.
Understanding how dependent clauses work and are formed is very important for being able to spot run-ons and fragments. Let's take a closer look at how they can be used in sentences.
Sentences with Dependent (or Subordinate) Clauses
Again, the terminology here isn't important, but the concept is. Like an independent clause, a dependent clause has a subject and a verb, but it doesn't make sense on its own.
Dependent clauses are usually used to describe the circumstances in which an independent clause occurs.
While she was gardening, Jenny found an old penny.
In this sentence, the dependent clause "While she was gardening", gives the context for when Jenny found the penny. Note that "while she was gardening" does not express a complete thought on its own — it's just setting the scene for more information to come. We will talk more about this later.
Be careful, because, when speaking, people often use dependent clauses in place of complete sentences. Imagine the following conversation:
You: “Look at this cool old penny I found! It’s from 1933!”
Friend: “Wow, that is cool. Where did you find that?”
You: “While I was gardening.”
Though we talk this way, it’s not acceptable in written English. Even in this conversation, “While I was gardening” is describing an independent clause you have already said - “Look at this cool old penny I found!” On the SAT, a sentence that only consists of a dependent clause will always be incorrect.
I will cover this idea in more detail in the “Fragments” section below.
Sentences with Prepositional Phrases, Appositives, and Relative Clauses
Some sentences include additional phrases or clauses that describe a noun or verb. There are a few different tupes, but none can replace a independent clause.
Prepositional phrases can be added to sentences to add more detail about something in the sentence. To learn more about prepositional phrases, see this article.
You can add a prepositional phrase almost anywhere in the sentence, depending on what the prepositional phrase is describing.
The man in my kitchen was making sandwiches.
The man was making sandwiches in my kitchen.
Remember that you should be able to completely delete the prepositional phase and still be left with a complete sentence:
The man was making sandwiches.
Also remember that a prepositional phrase cannot stand alone as a sentence:
In my kitchen. = INCORRECT
A relative clause gives extra information about a noun in the sentence — it often comes between the subject and the verb.
Relative clauses are so named because they begin with relative pronouns, like that, who, which, whose, or where.
The man, who was standing in my kitchen, was making sandwiches.
The man, whose sandwiches we enjoyed, works in the cafe down the street.
These can be removed from the sentence and a complete sentence will be left over:
The man was making sandwiches.
The man works in the cafe down the street.
An appositive is when a word or phrase that consists of a noun or pronoun (along with any descriptive words) is placed directly next to another noun in the sentence to re-state it and add a description. Appositives can be a single word, or a phrase (a group of words). Appositive are also set off by commas.
My dad, Phil, works in the cafe down the street.
My father, the man who is in the kitchen, likes making sandwiches.
Sandwiches, one of my favorite types of food, are delicious.
Appositives can also be crossed out and you will have a complete sentence left over.
My dad works in the cafe down the street.
My father likes making sandwiches.
Sandwiches are delicious.
Now that you know various ways to construct a correct, complete sentence, let's discuss some of the mistakes that students often make in doing so. We'll start with common pitfalls that cause incomplete sentences.
What is a Fragment?
A fragment is an incomplete sentence. There are 6 main mistakes that can make a sentence a fragment:
- A “sentence” that lacks a verb
- A “sentence” that has an -ing or non-past tense -ed verb without a helping verb
- A “sentence” that lack a subject
- A “sentence” that begins with a subordinating conjunction and has no main clause
- A “sentence” that add details to the main clause, but is separated from it
- A “sentence” that has a nonessential clause or prepositional phrase and incomplete main clause
Let's discuss each of these separately.
1. Sentences that do not have a verb
To recognize these kinds of fragments, ask yourself what the subject of the sentence is doing. If you can't answer that question, it's probably because there's no verb!
John, after winning the trophy. (What did he do?)
Ten cakes and two dozen cupcakes. (What about them?)
Next Tuesday. (What is next Tuesday?)
To fix these kinds of fragments, you must add a verb to show an action or state of being.
John, after winning the trophy, smiled.
Ten cakes and two dozen cupcakes were prepared by the bakery.
Next Tuesday is my birthday.
2. Sentences with a gerund or past participle and no helping verb.
These errors can be a bit more difficult to recognize. Whenever you see a gerund, an “-ing” verb, or a past participle, an “-ed” verb that doesn’t seem to be describing the past tense, there MUST be a helping verb with it or another verb somewhere else in the sentence. If the sentence has neither, it's a fragment.
The children walking through the park.
The paintings created by the students.
Students studying every night for the SAT.
The actress smiling at the crowd
There are two ways to fix these kinds of fragments. The first is to add a helping verb or change the verb to another form.
The children were walking through the park.
The paintings were created by the students.
The students had been studying every night for the SAT.
The actress was smiling at the crowd. <OR> The actress smiled at the crowd.
The second way to fix these fragments is to use the -ing or -ed word as a participle - meaning that it is an adjective describing a noun in the sentence - and add a main verb.
The children walking through the park shouted with joy.
The paintings created by the students were hung in the hallway.
The students studying every night for the SAT were sleep deprived.
The actress, smiling at the crowd, accepted the award.
3. A sentence is also a fragment if it lacks a subject.
To recognize this error, ask yourself: who is doing the action?
After reading all the assigned material. (Who read it?)
Wanted to discuss her grades with the teacher. (Who wanted to?)
Contemplating the meaning of life. (Who was?)
You may notice that some of these examples also have errors we have already discussed. To fix these, we need to add a subject and make sure there is a correctly conjugated main verb.
Phil went to bed after reading all the assigned material.
Amanda wanted to discuss her grades with the teacher.
She was contemplating the meaning of life.
4. A sentence is a fragment if it is a dependent or subordinate clause.
This means that it has both a subject and a verb in the correct form, but it begins with a subordinating conjunction and is not attached to another, main clause that is a complete sentence on its own.
To recognize these errors, see if the sentence begins with a subordinating conjunction. Some common subordinating conjunctions include: after, although, as, as if, because, before, ever since, if, in order, just as, since, so that, though, unless, until, when, whenever, where, whether, whereas, whichever, while.
While I was parking the car.
When he finished baking cupcakes.
Since she owns two horses.
To fix these errors, you need to connect them to an independent clause — a complete thought that can stand on its own.
While I was parking the car, I saw a cat run across the driveway.
When he finished baking cupcakes, I iced them.
Since she owns two horses, she is going to give me riding lessons.
5. Look out for added detail fragments.
These constructions come after a complete sentence and give extra information, but they don't express a complete thought on their own.
They usually begin with words like such as, including, and for example.
If you see a "sentence" that begins with one of the above words or phrases, check to see if it has a subject and a verb. If the subject and verb are part of another sentence, then it is a fragment.
I enjoy seeing animals at the zoo. Such as monkeys, zebras, and lions.
Julia enjoys watching anime. For example, YuYu Hakusho and Princess Mononoke.
I like to eat sweets, such as: donuts, chocolate, and candy.
These fragments can be fixed in several ways.
The first is to add the detail fragment to the main sentence it is describing.
I enjoy seeing animals such as monkeys, zebras, and lions at the zoo.
Additionally, you can make a complete sentence out of the fragment by adding a subject and a verb.
Julia enjoys watching anime. For example, she watches YuYu Hakusho and Princess Mononoke.
When one of the words introduces a list with a colon, make sure that what comes before the colon can stand on its own as a complete sentence.
I like to eat sweets: donuts, chocolate, and candy.
Or you can make a sentence without the colon.
I like to eat sweets, such as donuts, chocolate, and candy.
6. Some fragments will have a relative clause, appositive, or prepositional phrase with an incomplete main clause.
To spot these errors, cross out the relative clause, appositive, or prepositional phrase. Are you left with a complete sentence?
John, who won the trophy four years in a row. → John, who won the trophy four years in a row. (Missing verb)
In the newspapers. → In the newspapers. (Missing subject and verb)
The trophy, which was given to the person who could cook an omelette the fastest. → The trophy, which was given to the person who could cook an omelette the fastest. (Missing verb)
Santa Claus, the jolly man in the red suit. → Santa Claus, the jolly man in the red suit. (Missing verb)
To correct these errors, add a subject or a verb as needed. Make sure that if you eliminate the prepositional phrase or non-essential clause, that there is complete sentence left over.
John, who won the trophy four years in a row, congratulated his competitors.
John congratulated his competitors. = CORRECT
John’s victory was announced in the newspapers.
John’s victory was announced. = CORRECT
The trophy, which was given to the person who could cook an omelette the fastest, was shaped like an egg.
The trophy was shaped like an egg. = CORRECT
Santa Claus, the jolly man in the red suit, ate all my cookies.
Santa Claus ate all my cookies. = CORRECT
Now you know the ways to fix incomplete sentences!
Another common error that the SAT will test you on is whether you can recognize sentences that are incorrect because the clauses have been joined together incorrectly. Let's look at how to tackle these questions.
What is a Run-on?
A run-on is when two or more sentences run together and aren't separated by the correct punctuation. Some people think that “run-on” just means a really long sentence. This isn't true - you can have a very long sentence that is grammatically correct. This sentence is 239 words long but is not a run-on.
There are three main types of run-ons:
- Comma splices
- Fused sentences
- Sentences joined by a conjunctive adverb and commas
A comma splice occurs when two complete independent clauses (full sentences) are joined together by a comma and nothing else. A comma can never join together two complete sentences on its own.
When you see a sentence with a comma in the middle, check to see if there is a coordinating conjunction (see this article for more info) that joins the sentences together or if one of the clauses is a subordinate clause that begins with a subordinating conjunction. If not, the sentence is a run-on.
She was offered the prestigious job, she turned it down because she did not want to move to Texas.
Fused sentences occur when two or more sentences run right into each other, with no punctuation at all. To recognize these, look to see if a sentence has two unconnected subjects and verbs without the necessary punctuation (see above for the correct ways to join two independent clauses).
She was offered the prestigious job she turned it down because she did not want to move to Texas.
Incorrectly Punctuated Conjunctive Adverbs
Joining two independent clauses with a conjunctive adverb and commas is another recipe for a run-on.
Conjunctive adverbs can only be used to connect two independent clauses in concert with a period or a semicolon.
When you see a conjunctive adverb (however, moreover, nevertheless, therefore, consequently, etc.) with commas on either side of it, check whether it's being used to connect independent clauses on either side of it. If so, the sentence is a run-on.
She was offered the prestigious job, however, she turned it down because she did not want to move to Texas.
To fix run-ons, you will use the rules outlined above to correctly join two sentences:
1. Create two separate sentences.
She was offered the prestigious job. She turned it down because she did not want to move to Texas.
2. Use a comma and FANBOYS conjunction.
She was offered the prestigious job, but she turned it down because she did not want to move to Texas.
3. Use a semicolon.
She was offered the prestigious job; she turned it down because she did not want to move to Texas.
4. Use a semicolon with a conjunctive adverb.
She was offered the prestigious job; however, she turned it down because she did not want to move to Texas.
5. Re-write the sentence with a subordinate clause.
Depending on the sentence, this may not always be as easily done, and may require extra work.
Since she did not want to move to Texas, she turned down the prestigious job that she was offered.
6. If the two clauses have the same subject, join the sentences and remove the repeated subject.
Notice that this way, you do not need a comma with your FANBOYS conjunction.
She was offered the prestigious job but turned it down because she did not want to move to Texas.
Specific Strategies for Fragments and Run-ons
Fragments and run-ons will most frequently be tested in Improving Sentences questions, though they will also sometimes appear in Identifying Errors and Improving Paragraphs. Use the following steps to approach a fragment or run-on question:
1. When you first read the sentence, make sure you can find the subject and correctly conjugated verb.
Is this difficult? If you see a prepositional phrase, appositive, or a non-essential clause, cross it out. See if you have a correct sentence left over.
2. In both the original sentence and the answer choices, look for the telltale signs of a fragment or run-on error:
- -ed or -ing verbs. Check for appropriate helping verbs.
- Clause that begins with a subordinating conjunction. Check it is connected to a main clause.
- A separate sentence describing a previous sentence, with words like “for example.”
- Conjunctive adverbs like “however” surrounded by commas
- A semicolon followed by a FANBOYS conjunction
- A single comma in the middle of the sentence - often a sign of comma splice
3. Immediately cross out any answer choices that make the above errors.
4. IMPORTANT: One almost sure sign of a mistake is a non-essential clause that is not immediately followed by a verb. If you see one of these, it is almost always a fragment that needs fixing.
My father, who is one of the greatest violinists in the world, and he plays the piano, as well. → FRAGMENT
My father, who is one of the greatest violinists in the world, plays the piano, as well. → CORRECT
5. IMPORTANT: Watch out for commas separating two independent clauses (aka a comma splice). This is the most common type of run-on that you will see on the SAT.
6. Select a final answer choice that follows the above rules and also follows the standard style rules used on the Writing SAT:
- No unnecessary prepositions or articles
- Pronouns must have clear antecedents
- Use fewer gerunds and participles if possible
- No dangling or misplaced modifiers
- Choose the most concise option that is also grammatically correct.
Let’s try one together…
Santa Fe is one of the oldest cities in the United States, its adobe architecture, spectacular setting, and clear, radiant light have long made it a magnet for artists.
- Santa Fe is one of the oldest cities in the United States, its
- Santa Fe, which is one of the oldest cities in the Unites States, its
- Santa Fe, which is one of the oldest cities in the United States, has
- Santa Fe is one of the oldest cities in the United States; its
- Santa Fe, one of the oldest cities in the United States, and it
The first thing that I notice in this question is that part of the underlined portion contains a comma. This is a clue that I should check to see how it is being used. Commas are correctly used to separate items in a list and to separate dependent clauses from independent clauses. This is obviously not a list (though we do have a list at the end of the sentence) and I don’t see any subordinating conjunctions, so it’s not a dependent clause.
Now I need to check if I am dealing with a comma splice. Can I make two separate sentences out of the above by replacing the comma with a period?
Santa Fe is one of the oldest cities in the United States. Its adobe architecture, spectacular setting, and clear, radiant light have long made it a magnet for artists.
This works, so I'm dealing with a comma splice.
Now I’m going to look at the answer choices and see if I can spot some other obvious errors. Choice (A) is always the same as the original sentence, so it contains the comma splice. I can rule it out.
Choices (B) and (C) both contain non-essential clauses beginning with “which”. As I know from the rules above, I should always be able to cross out non-essential clauses and have a complete sentence left over. So let’s try that:
B: Santa Fe its adobe architecture, spectacular setting, and clear, radiant light have long made it a magnet for artists. → SENTENCE DOES NOT MAKE SENSE, so (B) is out.
C: Santa Fe has adobe architecture, spectacular setting, and clear radiant light have long made it a magnet for artists. → SENTENCE DOES NOT MAKE SENSE, so (C) is out.
Choice (D) uses a semicolon to separate the two independent clauses, which is one of the correct ways to join two sentences together. Therefore, answer (D) is correct.
But just to be certain, let’s look at answer (E). This option contains an appositive. We should be able to cross it out and have a correct sentence:
E: Santa Fe and it adobe architecture, spectacular setting, and clear, radiant light have long made it a magnet for artists. → SENTENCE DOES NOT MAKE SENSE, so (E) is out.
Now time to try some on your own!
Practice Questions from the SAT
#1: What must be done with sentence 2 below?
(1) The students in the class agreed - some of them unhappily - that they would all participate in the new book club. (2) Started by their literature professor, who also ran a film club on campus.
- Combine it with sentence 1, putting a comma after “club”.
- Begin it with the words “It was”.
- Replace the comma after "professor" with a semicolon.
- Replace the word "ran" by "was running".
- Change “professor, who” to “professor, she”
#2: Many people do not like anchovies on their pizza, it is because they think they taste bad and are disgusting as a result.
- pizza, it is because they think they taste bad and are disgusting as a result
- pizza because they think they taste bad and therefore find them disgusting
- pizza for the reason that they think they taste bad with resulting disgust
- pizza because of thinking they taste bad and therefore they think them disgusting
- pizza, their thoughts of them being that they taste bad resulting in finding them disgusting
#3: Having won gold in the Olympics two years in a row, the Brazilian women's soccer team praised for their athleticism.
- praised for their athleticism
- praised and were very athletic
- has been praised for its athleticism
- are praised for having athleticism
- is being praised for being athletic
#4: To assist the team in the timely production of the film, a revised script written overnight by the director and producer.
- a revised script written overnight by the director and producer.
- a revised script being written overnight by the director and producer
- and to write overnight a revised script by the director and producer
- the director and producer have written a revised script overnight
- with the director and producer writing a revised script overnight
#5: A form of dance traditional to northern Spain is the Flamenco, it combines rhythmic stamping with emotional intensity.
- Flamenco, it combines rhythmic stamping
- Flamenco, which combines rythmic stamping
- Flamenco, which lets them combine rhythmic stamping
- Flamenco; letting them combine rhythmic stamping
- Flamenco by having a combination of rhythmic stamping
#6: London's iconic Tower Bridge, which was opened on (A) June 30, 1894, to span the Thames River, and is crossed by (B) a minimum of (C) 40,000 people (D) per day. No error. (E)
Answers: 1. B; 2. B; 3. C; 4. D; 5. B; 6. B
Now that you’ve mastered one of the trickiest concepts on SAT Writing, time to check out some others! Read about how the SAT will test you on parallel structure, illogical comparisons, and wordiness and redundancy.
Need to review some of the basics before moving forward? Brush up on the fundamentals of grammar with our Parts of Speech guide.
Was this concept too easy? Check out some of the most difficult questions you’ll encounter on SAT Writing.
Aiming high? Read this article for top tips for a perfect Writing SAT score from a perfect scorer.
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Mary Ann holds a BA in Classics and Russian from the University of Notre Dame, and an MA from University College London. She has years of tutoring experience and is also passionate about travel and learning languages.