Two of the most common punctuation mistakes in student writing are the run-on sentence and the comma splice.
Run-On Sentences
A run-on sentence occurs when two or more independent clauses are connected in a sentence without the proper punctuation. Here is an example of a run-on sentence:
Incorrect:
- Paul had to stay up all night to finish the project he had put it off for weeks.
This is a run-on sentence because there are two complete, independent clauses but no punctuation. Therefore, we must add punctuation and/or change the sentence by adding or removing words:
Corrected:
- Paul had to stay up all night to finish the project; he had put it off for weeks.
Other options:
- Paul had to stay up all night to finish the project because he had put it off for weeks.
- Paul had to stay up all night to finish the project that he had been putting off for weeks.
Comma Splices
Students will often use a comma to connect two independent clauses without a conjunction (and, but, or, so, for, yet, nor). This use of the comma is not possible; it is a common mistake called a comma splice. Here is an example of a comma splice:
Incorrect:
- Sarah's father is a renowned classical pianist, her mother is a successful theatre actress.
When correcting a comma splice, you have several options to choose from. You can change the punctuation and/or add linking devices.
Corrected:
- Sarah's father is a renowned surgeon. Her mother is a successful theatre actress.
- Sarah's father is a renowned surgeon; her mother is a successful theatre actress.
- Sarah's father is a renowned surgeon, and her mother is a successful theatre actress.
- Sarah's father is a renowned surgeon whereas her mother is a successful theatre actress.
- Sarah's father is a renowned surgeon; similarly, her mother is a successful theatre actress.
One other way of avoiding a comma splice is by adding another independent clause to the sentence and thereby creating a series of three clauses:
- Sarah's father is a renowned surgeon, her mother is a successful theatre actress, and her brother is a respected hospital manager.
Review - Run-on Sentences and Comma Splices
Shaun explains run-on sentences and comma splices
Exercise
Using what you have learned about run-on sentences and comma splices, complete the activity.