A run-on sentence is a sentence that contains two or more independent clauses that are not properly separated by a comma or a semicolon. This can make the sentence difficult to read and understand.
For example, the following is a run-on sentence:
The cat sat on the mat the dog chased the ball.
This sentence is difficult to read because it is not clear where one sentence ends and the other begins. We can fix this by adding a comma or a semicolon to separate the two clauses.
The cat sat on the mat; the dog chased the ball.
The cat sat on the mat, and the dog chased the ball.
Both of these sentences are correct because they use proper punctuation to separate the two independent clauses.
Now that we know what a run-on sentence is, let's take a closer look at how to avoid them.
What is a Run-On Sentence
A run-on sentence occurs when two or more independent clauses are joined without proper punctuation.
- Independent clauses joined without punctuation
- Difficult to read and understand
- Use comma or semicolon to separate clauses
- Comma + coordinating conjunction
- Semicolon without conjunction
- Avoid comma splice: comma + subordinating conjunction
- Check for fused sentences: no punctuation or conjunction
- Use em dash or colon for dramatic effect
- Vary sentence structure for clarity
- Proofread for run-on sentences
By following these tips, you can avoid run-on sentences and write clear, concise prose.
Independent clauses joined without punctuation
One of the most common ways to create a run-on sentence is to join two or more independent clauses without using any punctuation. This can make it difficult for the reader to understand where one sentence ends and the next begins.
For example, the following sentence is a run-on sentence because the two independent clauses are joined without any punctuation:
The cat sat on the mat the dog chased the ball.
We can fix this run-on sentence by adding a comma or a semicolon to separate the two independent clauses:
The cat sat on the mat; the dog chased the ball.
The cat sat on the mat, and the dog chased the ball.
Both of these sentences are now grammatically correct because the independent clauses are properly separated.
Here are some additional examples of run-on sentences that are caused by independent clauses being joined without punctuation:
The sun was shining the birds were singing. I went to the store I bought some groceries. She loves to read she also loves to write.
All of these sentences can be fixed by adding a comma or a semicolon to separate the independent clauses.
It is important to note that not all sentences that have two or more independent clauses are run-on sentences. If the independent clauses are joined by a coordinating conjunction (such as and, but, or, nor, for, so, or yet), then the sentence is not a run-on sentence. For example, the following sentence is not a run-on sentence because the two independent clauses are joined by the coordinating conjunction "and":
The cat sat on the mat and the dog chased the ball.
Difficult to read and understand
Run-on sentences can be difficult to read and understand because they can make it difficult for the reader to follow the flow of the sentence. When two or more independent clauses are joined without proper punctuation, the reader may have to stop and reread the sentence in order to figure out what the author is trying to say.
For example, consider the following run-on sentence:
The cat sat on the mat the dog chased the ball.
This sentence is difficult to read and understand because the reader has to stop and figure out where one sentence ends and the next begins. The reader may also have to reread the sentence in order to understand the relationship between the two clauses.
Now, let's look at the same sentence with proper punctuation:
The cat sat on the mat; the dog chased the ball.
This sentence is much easier to read and understand because the semicolon separates the two independent clauses. The reader can now easily see that the cat sat on the mat and the dog chased the ball. The reader can also understand the relationship between the two clauses: the dog chased the ball because the cat sat on the mat.
Here are some additional examples of run-on sentences that are difficult to read and understand:
I went to the store I bought some groceries. She loves to read she also loves to write. The sun was shining the birds were singing.
All of these sentences are difficult to read and understand because the independent clauses are not properly separated. The reader has to stop and reread the sentences in order to understand what the author is trying to say.
By avoiding run-on sentences, you can make your writing easier to read and understand. Your readers will appreciate it!
Use comma or semicolon to separate clauses
The most common way to fix a run-on sentence is to use a comma or a semicolon to separate the independent clauses.
- Use a comma + coordinating conjunction
When you use a comma to separate two independent clauses, you must also use a coordinating conjunction (such as and, but, or, nor, for, so, or yet). For example:
The cat sat on the mat, and the dog chased the ball.
I went to the store, but I forgot my wallet.
- Use a semicolon without a conjunction
You can also use a semicolon to separate two independent clauses, but you do not need to use a coordinating conjunction. For example:
The cat sat on the mat; the dog chased the ball.
I went to the store; I forgot my wallet.
- Avoid comma splice: comma + subordinating conjunction
Do not use a comma to separate two independent clauses if the second clause begins with a subordinating conjunction (such as although, because, since, unless, or until). This is called a comma splice, and it is a grammatical error. For example:
The cat sat on the mat, although the dog was chasing the ball. (incorrect)
The cat sat on the mat because the dog was chasing the ball. (correct)
- Check for fused sentences: no punctuation or conjunction
Finally, check for fused sentences, which occur when two independent clauses are joined with no punctuation or conjunction. Fused sentences are also grammatical errors. For example:
The cat sat on the mat the dog chased the ball. (incorrect)
The cat sat on the mat, and the dog chased the ball. (correct)
By following these tips, you can use commas and semicolons correctly to separate independent clauses and avoid run-on sentences.
Comma + coordinating conjunction
One of the most common ways to fix a run-on sentence is to use a comma followed by a coordinating conjunction to join the two independent clauses. Coordinating conjunctions are words like and, but, or, nor, for, so, and yet. They are used to connect two words, phrases, or clauses that are grammatically equal.
When you use a comma and a coordinating conjunction to join two independent clauses, the comma goes before the coordinating conjunction. For example:
The cat sat on the mat, and the dog chased the ball.
I went to the store, but I forgot my wallet.
She loves to read, and she also loves to write.
Using a comma and a coordinating conjunction is a simple and effective way to fix a run-on sentence. However, there are a few things to keep in mind:
- Do not use a comma and a coordinating conjunction to join two clauses if the second clause begins with a subordinating conjunction. Subordinating conjunctions are words like although, because, since, unless, and until. For example:
The cat sat on the mat, although the dog was chasing the ball. (incorrect)
This is a comma splice, which is a grammatical error. The correct way to write this sentence is:
The cat sat on the mat because the dog was chasing the ball.
- Do not use a comma and a coordinating conjunction to join two clauses if the second clause is a fragment. A fragment is an incomplete sentence that cannot stand on its own. For example:
The cat sat on the mat, and chasing the ball. (incorrect)
This is a comma splice, which is a grammatical error. The correct way to write this sentence is:
The cat sat on the mat and chased the ball.
By following these tips, you can use commas and coordinating conjunctions correctly to join independent clauses and avoid run-on sentences.
Semicolon without conjunction
Another way to fix a run-on sentence is to use a semicolon to separate the two independent clauses. A semicolon is a stronger form of punctuation than a comma, so it is used when the two clauses are closely related but not as closely related as two clauses that are joined by a comma and a coordinating conjunction.
When you use a semicolon to join two independent clauses, you do not need to use a coordinating conjunction. For example:
The cat sat on the mat; the dog chased the ball.
I went to the store; I forgot my wallet.
She loves to read; she also loves to write.
Using a semicolon without a conjunction is a good way to create a more formal and sophisticated tone in your writing. However, it is important to use semicolons correctly. Here are a few things to keep in mind:
- Do not use a semicolon to join two clauses that are not closely related. For example:
The cat sat on the mat; the sky is blue. (incorrect)
These two clauses are not closely related, so a semicolon is not appropriate. The correct way to write this sentence is:
The cat sat on the mat. The sky is blue.
- Do not use a semicolon to join two clauses if the second clause begins with a coordinating conjunction. For example:
The cat sat on the mat; and the dog chased the ball. (incorrect)
This is a comma splice, which is a grammatical error. The correct way to write this sentence is:
The cat sat on the mat, and the dog chased the ball.
- Do not use a semicolon to join two clauses if the second clause is a fragment. For example:
The cat sat on the mat; chasing the ball. (incorrect)
This is a comma splice, which is a grammatical error. The correct way to write this sentence is:
The cat sat on the mat and chased the ball.
By following these tips, you can use semicolons correctly to join independent clauses and avoid run-on sentences.
Avoid comma splice: comma + subordinating conjunction
A comma splice is a grammatical error that occurs when two independent clauses are joined with only a comma. Subordinating conjunctions are words like although, because, since, unless, and until. They are used to connect a dependent clause to an independent clause.
- Do not use a comma to join two independent clauses if the second clause begins with a subordinating conjunction.
For example:
The cat sat on the mat, although the dog was chasing the ball. (incorrect)
This is a comma splice. The correct way to write this sentence is:
The cat sat on the mat because the dog was chasing the ball.
- Use a semicolon to join two independent clauses if the second clause begins with a subordinating conjunction.
For example:
The cat sat on the mat; although the dog was chasing the ball, the cat did not move.
- Use a comma + coordinating conjunction to join two independent clauses if the second clause does not begin with a subordinating conjunction.
For example:
The cat sat on the mat, and the dog chased the ball.
- Revise the sentence to avoid using a comma splice.
For example, you could rewrite the following sentence to avoid a comma splice:
The cat sat on the mat, although the dog was chasing the ball. (incorrect)
as:
Although the dog was chasing the ball, the cat sat on the mat.
By following these tips, you can avoid comma splices and write grammatically correct sentences.
Check for fused sentences: no punctuation or conjunction
A fused sentence is a grammatical error that occurs when two independent clauses are joined with no punctuation or conjunction. This can make the sentence difficult to read and understand.
- Look for sentences that are missing a comma or semicolon.
For example:
The cat sat on the mat the dog chased the ball. (fused sentence)
This sentence is missing a comma or semicolon after "mat." The correct way to write this sentence is:
The cat sat on the mat, and the dog chased the ball.
- Look for sentences that are missing a coordinating conjunction.
For example:
The cat sat on the mat and the dog chased the ball. (fused sentence)
This sentence is missing a coordinating conjunction after "mat." The correct way to write this sentence is:
The cat sat on the mat, and the dog chased the ball.
- Look for sentences that have two verbs but only one subject.
For example:
The cat sat on the mat chased the ball. (fused sentence)
This sentence has two verbs ("sat" and "chased") but only one subject ("cat"). The correct way to write this sentence is:
The cat sat on the mat and chased the ball.
- Revise the sentence to avoid the fused sentence.
For example, you could rewrite the following sentence to avoid a fused sentence:
The cat sat on the mat the dog chased the ball. (fused sentence)
as:
The cat sat on the mat. The dog chased the ball.
By following these tips, you can check for and avoid fused sentences in your writing.
Use em dash or colon for dramatic effect
While commas, semicolons, and coordinating conjunctions are the most common ways to join independent clauses, you can also use an em dash or a colon for dramatic effect. However, these punctuation marks should be used sparingly.
Em dash
An em dash is a long dash that is used to set off a phrase or clause that is grammatically independent but closely related to the rest of the sentence. Em dashes can be used to add emphasis, suspense, or surprise.
For example:
The cat sat on the mat — and then the dog came along.
I have a surprise for you — a new puppy!
The cat — a sly creature — crept up on the mouse.
Colon
A colon is used to introduce a list, a quotation, or an explanation. Colons can also be used to create a sense of anticipation or suspense.
For example:
The following items are required: a pen, a notebook, and a calculator.
The president said: "We will not give up."
The question is: what is the meaning of life?
When used correctly, em dashes and colons can add variety and interest to your writing. However, it is important to use them sparingly and appropriately.