1. Run-Ons and Comma Splices
“Commas [should] fall with the precision of knives in a circus act, outlining the victim.” – E.B. White

2. What is a run-on sentence?
A run-on sentence is also sometimes called a comma splice.
A run-on is formed when a writer attempts to join two complete sentences (independent clauses) incorrectly, most often with a comma.
A comma is not sufficient to join two complete sentences.

3. Comma Splices:
I realized that my boyfriend cheated on me with my best friend, I plotted his demise.
The field lay open and desolate against the cold winter sky, the birds circled ominously over the vacant plains.
Ava left for Europe, her flight is at one o’clock.
Macaroni is found in aisle seven, sherbet is in the freezer section in aisle twelve.

4. How do I fix a comma splice?
There are four basic ways to correct a comma splice.
Insert end punctuation and begin a new sentence.
Use a semicolon.
Use a comma and a coordinating conjunction.
Use a subordinating conjunction in one of the clauses.

5. Correction: Make Two Sentences.
The easiest way to fix a comma splice is to make two sentences.
To do this, insert end punctuation (period, exclamation mark, question mark) and begin a new sentence.

6. Correction: Make Two Sentences.
Incorrect:
Ava left for Europe, her flight is at one o’clock.
Mr. Smith wandered the halls, he was looking for room 388.
Correct:
Ava left for Europe. Her flight is at one o’clock.
Mr. Smith wandered the halls. He was looking for room 388.

7. Correction: Use a Semicolon.
A semicolon is used to join two complete sentences.
When using a semicolon, the two sentences should be related in their subject or meaning.

8. Correction: Use a Semicolon.
Incorrect:
I realized that my boyfriend cheated on me with my best friend, I plotted his demise.
No one likes a thief, put that candy bar back!
Correct:
I realized that my boyfriend cheated on me with my best friend; I plotted his demise.
No one likes a thief; put that candy bar back!

9. Correction: Use a Coordinating Conjunction and a Comma.
Coordinating conjunctions are: but, or, yet, for, and, nor, so.
The comma should appear at the end of the first complete sentence, followed by a coordinating conjunction and the second complete sentence.

10. Correction: Use a Coordinating Conjunction and a Comma.
Incorrect:
The field lay open and desolate against the cold winter sky, the birds circled ominously over the vacant plains.
I’d like a new iPod for Christmas, I don’t know which one.
Correct:
The field lay open and desolate against the cold winter sky, and the birds circled ominously over the vacant plains.
I’d like a new iPod for Christmas, yet I don’t know which one.

11. Correction: Use a Subordinating Conjunction
By including a subordinating conjunction in one of the independent clauses, you transform it into a dependent clause.
Then, you may join the two clauses with a comma.
Subordinating conjunctions include, but are not limited to: after, although, before, unless, as, because, even though, if, since, until, when, while.

12. Correction: Use a Subordinating Conjunction
Incorrect:
Macaroni is found in aisle seven, sherbet is in the freezer section in aisle twelve.
Kyle was fifteen minutes late for his first date with Janice, she went out with him anyway.
Correct:
Macaroni is found in aisle seven, while sherbet is in the freezer section in aisle twelve.
Even though Kyle was fifteen minutes late for his first date with Janice, she went out with him anyway.