How to fix run on sentences
What is a run on sentence?
A run-on sentence occurs when two or more independent clauses (complete sentences) are joined together without appropriate punctuation or conjunctions. To fix a run-on sentence, you must separate the clauses using a period, a semicolon, a coordinating conjunction (FANBOYS), or by subordinating one of the clauses.
Types of run-on sentences
Run-on sentences typically fall into two categories. A fused sentence happens when two independent clauses run together with no punctuation at all. A comma splice occurs when two independent clauses are joined by only a comma without a coordinating conjunction. Both errors disrupt the flow of academic writing and make arguments difficult to follow.
Methods to fix run-on sentences
| Method | Action | Best Use Case | Tone | Impact on Flow |
|---|---|---|---|---|
| Period | Create two separate sentences | Emphasizing distinct points | Formal | Stops momentum |
| Semicolon | Join with a semicolon (;) | Connecting closely related ideas | Academic | Smooth transition |
| Comma + FANBOYS | Add comma and conjunction | Showing relationships (cause/effect) | Balanced | Continuous flow |
| Subordination | Add words like 'because' or 'although' | Showing hierarchy of ideas | Analytical | Complex structure |
| Semicolon + Adverb | Use ';' + 'however' or 'therefore' | Logical transitions | Sophisticated | High clarity |
| Dash | Use an em dash (—) | Adding emphasis or side notes | Stylistic | Sharp break |
Examples: Before and after
### Comma Splice (Incorrect) The experiment failed, the temperature was too high. *Annotation: Two independent clauses joined only by a comma.* ### Fused Sentence (Incorrect) The experiment failed the temperature was too high. *Annotation: Two independent clauses with no punctuation between them.* ### Corrected Version 1: The Period The experiment failed. The temperature was too high. ### Corrected Version 2: The Semicolon The experiment failed; the temperature was too high. ### Corrected Version 3: The Conjunction The experiment failed because the temperature was too high.
The breath test for run-on sentences
Read your essay out loud. If you find yourself needing to take a breath in the middle of a sentence where there is no punctuation, you have likely found a run-on. In academic writing, favor the semicolon or the subordinating conjunction to maintain a sophisticated flow while keeping your clauses distinct.
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