Run-On Sentences: A Complete Guide for Students.

If you’ve ever written a sentence that felt like it went on forever—or got feedback saying, “This is a run-on sentence!”—don’t worry, you’re not alone. Run-on sentences are one of the most common mistakes in writing, especially for students preparing for exams like IGCSE. But here’s the good news: understanding and fixing run-on sentences is easier than you think!

In this blog, we’ll explore what run-on sentences are, why they happen, how to identify them, and how to fix them. Plus, we’ll have plenty of examples (and solutions) to make things clear and fun.

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What Are Run-On Sentences?

A run-on sentence happens when two or more independent clauses (complete thoughts) are joined incorrectly, either without punctuation or with the wrong punctuation.

The Two Common Types of Run-Ons

1. Fused Sentence: Two sentences are “fused” together with no punctuation at all.

   • Example: I love ice cream it’s my favorite dessert.

2. Comma Splice: Two sentences are joined by a comma without a conjunction.

   • Example: I love ice cream, it’s my favorite dessert.

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Why Do Students Write Run-On Sentences?

1. Writing Like They Speak:
   Spoken language often flows without clear breaks, but writing needs structure.

2. Not Knowing Where to Stop:
   Students sometimes confuse phrases and clauses or don’t recognize when a thought is complete.

3. Fear of Short Sentences:
   Some students think longer sentences sound more sophisticated. While this can be true, length should never come at the cost of clarity.

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How to Identify a Run-On Sentence

Ask yourself these questions:

• Does the sentence have two or more complete thoughts (independent clauses)?
• Are those thoughts joined incorrectly (missing punctuation or conjunctions)?

If the answer is “yes,” you’ve got a run-on!

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10 Examples of Fused Sentences (and How to Fix Them)

1. Fused Sentence: I went to the store I forgot my wallet.

   • Fix: I went to the store. I forgot my wallet.

2. Fused Sentence: The movie was amazing I couldn’t stop laughing.

   • Fix: The movie was amazing, and I couldn’t stop laughing.

3. Fused Sentence: She loves dancing her friends don’t.

   • Fix: She loves dancing, but her friends don’t.

4. Fused Sentence: I woke up late I missed the bus.

   • Fix: I woke up late, so I missed the bus.

5. Fused Sentence: The dog barked the cat ran away.

   • Fix: The dog barked; the cat ran away.

6. Fused Sentence: I wanted to play outside it started raining.

   • Fix: I wanted to play outside, but it started raining.

7. Fused Sentence: The test was hard everyone struggled with it.

   • Fix: The test was hard. Everyone struggled with it.

8. Fused Sentence: He didn’t study he still passed.

   • Fix: He didn’t study; he still passed.

9. Fused Sentence: The sunset was beautiful I took a picture.

   • Fix: The sunset was beautiful, so I took a picture.

10. Fused Sentence: I finished my homework I watched TV.

    • Fix: I finished my homework, and I watched TV.

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10 Examples of Comma Splices (and How to Fix Them)

1. Comma Splice: She loves chocolate, she hates vanilla.

   • Fix: She loves chocolate, but she hates vanilla.

2. Comma Splice: The train was late, we waited for hours.

   • Fix: The train was late. We waited for hours.

3. Comma Splice: I studied all night, I still failed.

   • Fix: Although I studied all night, I still failed.

4. Comma Splice: He’s a great player, his team always wins.

   • Fix: He’s a great player, and his team always wins.

5. Comma Splice: The party was fun, everyone danced.

   • Fix: The party was fun; everyone danced.

6. Comma Splice: I love summer, it’s so warm.

   • Fix: I love summer because it’s so warm.

7. Comma Splice: The cake was delicious, I had three slices.

   • Fix: The cake was delicious. I had three slices.

8. Comma Splice: I ran to the park, my friends were waiting there.

   • Fix: I ran to the park where my friends were waiting.

9. Comma Splice: We watched a movie, it was boring.

   • Fix: We watched a movie, but it was boring.

10. Comma Splice: She studied hard, she aced the exam.

    • Fix: She studied hard, so she aced the exam.

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How to Avoid Run-On Sentences

1. Understand Independent Clauses:

   • Each independent clause needs its own subject and verb.

2. Learn the Tools to Join Clauses:

   • Periods: Separate two thoughts completely.
   • Commas + Conjunctions: Use a conjunction like and, but, so, or yet with a comma.
   • Semicolons: Join closely related ideas.

3. Keep It Simple:

   • Short sentences are better than confusing ones.

4. Read Your Work Aloud:

   • You’ll often “hear” where a sentence feels too long or jumbled.