Run-On Sentences & Comma Splices: Fix Them Easily

1. Introduction to Two Common Errors

In English writing, two of the most common errors are the run-on sentence and the comma splice. Both occur when two complete sentences are joined incorrectly into one sentence.

Understanding and fixing these errors is essential because they are considered basic mistakes. They can lower your grades, damage your professional credibility, and reduce your exam scores.

The Difference

Error	What Happens
Run-on sentence	Two sentences joined with no punctuation at all.
Comma splice	Two sentences joined only with a comma.

Examples at a Glance

Incorrect	Type of Error
I like your haircut it looks really good.	Run-on
I like your haircut, it looks really good.	Comma splice
My brother is a doctor he works at a hospital.	Run-on
My brother is a doctor, he works at a hospital.	Comma splice

Word Meaning Section

Word / Phrase	English Meaning	Bengali Meaning
Run-on sentence	two sentences without proper break	দুটি বাক্য একসাথে জুড়ে দেওয়া
Comma splice	two sentences joined only by comma	কমা দিয়ে দুটি বাক্য জোড়া
Punctuation	marks like period, comma	যতিচিহ্ন
Semicolon	mark (;) separating related sentences	সেমিকোলন
Conjunction	word connecting clauses	সংযোজক অব্যয়

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2. Understanding Run-On Sentences

A run-on sentence occurs when two independent clauses (complete sentences) are written as one sentence without any punctuation or conjunction between them.

8 Examples of Run-On Sentences with Explanations

#	Run-On Sentence	Explanation
1	I like your haircut it looks really good.	Two sentences: “I like your haircut.” + “It looks really good.” No punctuation.
2	My brother is a doctor he works at a hospital.	“My brother is a doctor.” + “He works at a hospital.” No break.
3	People are buying books online bookstores are closing.	“People are buying books online.” + “Bookstores are closing.” No break.
4	She loves to read she visits the library often.	Two complete thoughts stuck together.
5	The weather was terrible we stayed inside.	Second sentence directly follows first.
6	He finished the report he submitted it late.	No conjunction or period.
7	The team won the match they celebrated all night.	Two independent clauses.
8	I called him he didn’t answer.	Both parts have subject and verb.

Word Meaning Section

Word / Phrase	English Meaning	Bengali Meaning
Independent clause	a complete sentence	স্বাধীন খণ্ডবাক্য
Subject	who or what the sentence is about	কর্তা
Verb	action or state	ক্রিয়া
Complete thought	an idea that can stand alone	সম্পূর্ণ চিন্তা

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3. Understanding Comma Splices

A comma splice occurs when two independent clauses are joined only by a comma, without a coordinating conjunction. This is also incorrect because a comma alone cannot join two strong independent sentences.

8 Examples of Comma Splices with Explanations

#	Comma Splice	Explanation
1	I like your haircut, it looks really good.	Two sentences joined by comma only.
2	My brother is a doctor, he works at a hospital.	Comma does not properly separate.
3	People are buying books online, bookstores are closing.	Need stronger punctuation or conjunction.
4	She loves to read, she visits the library often.	Comma instead of period or semicolon.
5	The weather was terrible, we stayed inside.	Two independent clauses with comma only.
6	He finished the report, he submitted it late.	Comma instead of conjunction.
7	The team won the match, they celebrated all night.	Comma splice.
8	I called him, he didn’t answer.	Both sentences have subject and verb.

Word Meaning Section

Word / Phrase	English Meaning	Bengali Meaning
Comma	punctuation mark (,)	কমা
Splice	to join incorrectly	ভুলভাবে জোড়া
Clause	group of words with subject and verb	খণ্ডবাক্য
Separator	something that divides	বিভাজক

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4. Why These Errors Matter in Exams and Writing

Run-on sentences and comma splices are not just stylistic preferences; they are grammatical errors. In exams, job applications, and academic writing, they can significantly affect your score and credibility.

8 Reasons to Fix These Errors

#	Reason	Explanation
1	Basic grammar	Shows lack of fundamental punctuation control.
2	IELTS / TOEFL scores	Lower grammatical range and accuracy band.
3	University assignments	Professors deduct marks.
4	Professional emails	Looks unprofessional and careless.
5	Clarity	Correct punctuation helps reader understand.
6	Confidence	Knowing the rules builds confidence.
7	Advanced writing	Semicolons and complex sentences raise level.
8	Prevents confusion	Two ideas blended can confuse meaning.

Word Meaning Section

Word / Phrase	English Meaning	Bengali Meaning
Credibility	trustworthiness	বিশ্বাসযোগ্যতা
Deduct	subtract	বাদ দেওয়া
Accuracy	correctness	নির্ভুলতা
Professional	competent and polished	পেশাদার
Range	variety	পরিসর

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5. Fix #1: Separate with a Period

The simplest way to fix a run-on sentence or comma splice is to separate the two independent clauses with a period and begin the second sentence with a capital letter.

The Rule

Sentence 1 + period + Sentence 2 (capital letter)

8 Examples of Correction Using Period

#	Incorrect	Correct (Period Fix)
1	I like your haircut it looks really good.	I like your haircut. It looks really good.
2	My brother is a doctor he works at a hospital.	My brother is a doctor. He works at a hospital.
3	People are buying books online bookstores are closing.	People are buying books online. Bookstores are closing.
4	She loves to read she visits the library often.	She loves to read. She visits the library often.
5	The weather was terrible we stayed inside.	The weather was terrible. We stayed inside.
6	He finished the report he submitted it late.	He finished the report. He submitted it late.
7	The team won the match they celebrated all night.	The team won the match. They celebrated all night.
8	I called him he didn’t answer.	I called him. He didn’t answer.
9	They studied hard they passed the exam.	They studied hard. They passed the exam.
10	The movie was long it was entertaining.	The movie was long. It was entertaining.

Word Meaning Section

Word	English Meaning	Bengali Meaning
Period	full stop (.)	দাঁড়ি
Capital letter	uppercase letter	বড় হাতের অক্ষর
Separate	to divide	আলাদা করা
Sentence	a complete unit of words	বাক্য

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6. Fix #2: Use a Semicolon

A semicolon (;) can join two closely related independent clauses without a conjunction. It is a more advanced punctuation mark that adds sophistication to your writing.

The Rule

Sentence 1 + ; + Sentence 2 (lowercase unless proper noun)

8 Examples of Correction Using Semicolon

#	Incorrect	Correct (Semicolon Fix)
1	People are buying books online bookstores are closing.	People are buying books online; bookstores are closing.
2	I like your haircut it looks really good.	I like your haircut; it looks really good.
3	My brother is a doctor he works at a hospital.	My brother is a doctor; he works at a hospital.
4	She loves to read she visits the library often.	She loves to read; she visits the library often.
5	The weather was terrible we stayed inside.	The weather was terrible; we stayed inside.
6	He finished the report he submitted it late.	He finished the report; he submitted it late.
7	The team won the match they celebrated all night.	The team won the match; they celebrated all night.
8	I called him he didn’t answer.	I called him; he didn’t answer.
9	The economy is growing jobs are being created.	The economy is growing; jobs are being created.
10	She was exhausted she kept working.	She was exhausted; she kept working.

Word Meaning Section

Word	English Meaning	Bengali Meaning
Semicolon	punctuation mark (;)	সেমিকোলন
Related	connected	সম্পর্কিত
Sophisticated	advanced	উন্নত
Closely linked	tightly connected	ঘনিষ্ঠভাবে যুক্ত

Important Note

After a semicolon, do not capitalize the first letter unless it is a proper noun or the pronoun “I”.

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7. Fix #3: Create a Compound Sentence (FANBOYS)

You can combine two independent clauses into a compound sentence by using a comma + coordinating conjunction. The seven coordinating conjunctions can be remembered with the acronym FANBOYS.

FANBOYS

Letter	Conjunction
F	for
A	and
N	nor
B	but
O	or
Y	yet
S	so

The Rule

Sentence 1 + , + coordinating conjunction + Sentence 2

8 Examples of Correction Using FANBOYS

#	Incorrect	Correct (Compound Sentence)
1	People are buying books online bookstores are closing.	People are buying books online, so bookstores are closing.
2	I like your haircut it looks really good.	I like your haircut, and it looks really good.
3	My brother is a doctor he works at a hospital.	My brother is a doctor, and he works at a hospital.
4	She loves to read she visits the library often.	She loves to read, so she visits the library often.
5	The weather was terrible we stayed inside.	The weather was terrible, so we stayed inside.
6	He finished the report he submitted it late.	He finished the report, but he submitted it late.
7	The team won the match they celebrated all night.	The team won the match, so they celebrated all night.
8	I called him he didn’t answer.	I called him, but he didn’t answer.
9	She was exhausted she kept working.	She was exhausted, yet she kept working.
10	The store was closed we went home.	The store was closed, so we went home.

Word Meaning Section

Word	English Meaning	Bengali Meaning
Coordinating conjunction	connects equal clauses	সংযোজক অব্যয়
Compound sentence	two independent clauses joined	যৌগিক বাক্য
FANBOYS	memory aid for conjunctions	সাতটি সংযোজকের স্মৃতিসহায়ক
Comma	punctuation mark (,)	কমা

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8. Fix #4: Create a Complex Sentence (Subordinating Conjunctions)

You can also combine the two clauses into a complex sentence by using a subordinating conjunction. This is the most advanced option.

Subordinating Conjunctions

Conjunction	Example
because	because people are buying books online
before	before the store closed
after	after the match ended
although	although it was long
though	though he tried
as	as the economy grows
since	since she was tired
when	when I called

The Rule

Dependent clause first + , + independent clause
or
Independent clause + dependent clause (no comma)

8 Examples of Correction Using Complex Sentence

#	Incorrect	Correct (Complex Sentence)
1	People are buying books online bookstores are closing.	Because people are buying books online, bookstores are closing.
2	I like your haircut it looks really good.	I like your haircut because it looks really good.
3	My brother is a doctor he works at a hospital.	My brother is a doctor, and he works at a hospital. (Actually compound; for complex: My brother works at a hospital because he is a doctor.)
4	She loves to read she visits the library often.	Since she loves to read, she visits the library often.
5	The weather was terrible we stayed inside.	Because the weather was terrible, we stayed inside.
6	He finished the report he submitted it late.	Although he finished the report, he submitted it late.
7	The team won the match they celebrated all night.	After the team won the match, they celebrated all night.
8	I called him he didn’t answer.	When I called him, he didn’t answer.
9	She was exhausted she kept working.	Although she was exhausted, she kept working.
10	The store was closed we went home.	Because the store was closed, we went home.

Word Meaning Section

Word	English Meaning	Bengali Meaning
Subordinating conjunction	joins dependent clause to independent	অধীন সংযোজক
Complex sentence	independent + dependent clause	জটিল বাক্য
Dependent clause	cannot stand alone	অধীন খণ্ডবাক্য
Independent clause	can stand alone	স্বাধীন খণ্ডবাক্য
Comma after dependent clause	needed when dependent first	অধীন বাক্যের পরে কমা

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9. Grammar Focus: Independent and Dependent Clauses

Independent Clause

A group of words with a subject and verb that expresses a complete thought and can stand alone as a sentence.

• Example: “Bookstores are closing.”
• Can be a sentence alone.

Dependent Clause

A group of words with a subject and verb that does not express a complete thought. It depends on an independent clause.

• Example: “Because people are buying books online”
• Cannot stand alone; it needs the main clause.

Sentence Types

Type	Structure	Example
Simple sentence	One independent clause	Books are online.
Compound sentence	Two independent clauses + coordinating conjunction	People buy online, and stores close.
Complex sentence	One independent + one dependent clause	Because people buy online, stores close.
Compound-complex	Two independent + one dependent	Because people buy online, stores close, and jobs are lost.

Affirmative, Negative, and Interrogative Forms

Form	Example
Affirmative	People buy books online.
Negative	People don’t buy books offline.
Interrogative	Do people buy books online?
Affirmative compound	People buy online, and stores close.
Negative compound	People don’t buy offline, and stores don’t close.
Interrogative compound	Do people buy online, and do stores close?

5 WH-Question Examples with Answers

#	WH Question	Possible Answer
1	Why are bookstores closing?	Because people are buying books online.
2	What caused the run-on sentence?	Two sentences were joined without punctuation.
3	When should you use a semicolon?	When two ideas are closely related.
4	How can you fix a comma splice?	By adding a period, semicolon, or conjunction.
5	Which conjunction shows contrast?	“But” or “yet” show contrast.

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10. Sentence Patterns and Examples for Each Fix

Pattern 1: Period

Sentence. Sentence.

Pattern 2: Semicolon

Sentence; sentence.

Pattern 3: Compound (FANBOYS)

Sentence, conjunction sentence.

Pattern 4: Complex (Subordinating)

Dependent clause, independent clause.

or

Independent clause dependent clause.

8 Additional Examples Across Patterns

#	Original Incorrect	Period Fix	Semicolon Fix	Compound Fix	Complex Fix
1	The test was hard I studied a lot.	The test was hard. I studied a lot.	The test was hard; I studied a lot.	The test was hard, but I studied a lot.	Although the test was hard, I studied a lot.
2	She sings well she plays piano.	She sings well. She plays piano.	She sings well; she plays piano.	She sings well, and she plays piano.	She sings well because she practices.
3	It rained heavily the game continued.	It rained heavily. The game continued.	It rained heavily; the game continued.	It rained heavily, but the game continued.	Although it rained heavily, the game continued.
4	He was late he missed the train.	He was late. He missed the train.	He was late; he missed the train.	He was late, so he missed the train.	Because he was late, he missed the train.
5	The food was spicy I loved it.	The food was spicy. I loved it.	The food was spicy; I loved it.	The food was spicy, but I loved it.	Although the food was spicy, I loved it.
6	The course is difficult it is useful.	The course is difficult. It is useful.	The course is difficult; it is useful.	The course is difficult, but it is useful.	Although the course is difficult, it is useful.
7	I was tired I went to bed early.	I was tired. I went to bed early.	I was tired; I went to bed early.	I was tired, so I went to bed early.	Because I was tired, I went to bed early.
8	The team practiced hard they improved.	The team practiced hard. They improved.	The team practiced hard; they improved.	The team practiced hard, so they improved.	Because the team practiced hard, they improved.

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11. Special Tips for Learners

Tip 1: Identify the Two Sentences

Find where the first complete thought ends and the second begins.

Tip 2: Choose One Method and Master It First

Start with the period fix; it’s the easiest. Later, experiment with semicolons and complex sentences.

Tip 3: Use Semicolons to Sound Advanced

A semicolon is a favorite of academic writers; use it when ideas are closely connected.

Tip 4: Remember FANBOYS

Memorize: for, and, nor, but, or, yet, so.

Tip 5: Practice Subordinating Conjunctions

Because, since, although, when, after—these make your writing more nuanced.

Tip 6: Read Your Writing Aloud

Pause where the period should be; if you can’t pause, you may have a run-on.

Tip 7: Check After Writing

After finishing an essay, search for commas between two complete sentences and fix them.

Tip 8: Use a Grammar Checker

Tools can highlight these errors, but learn the rules yourself.

Tip 9: Vary Your Sentence Structure

Don’t always use periods; mix semicolons and complex sentences for style.

Tip 10: Review Official IELTS/TOEFL Writing Samples

Notice how they join clauses correctly.

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12. Tips for Competitive Exams: IELTS, TOEFL, GRE

IELTS

Skill	How It Is Tested	Strategy
Writing Task 2	Essay writing	Vary sentence types; avoid run-ons.
Grammar Range	Higher band needs complex structures	Use subordinate clauses correctly.
Coherence	Clear connection between ideas	Use semicolons and conjunctions appropriately.

TOEFL

Skill	How It Is Tested	Strategy
Writing Independent	Argument essay	Use compound and complex sentences.
Writing Integrated	Summarizing	Proper punctuation in long sentences.

GRE

Skill	How It Is Tested	Strategy
Analytical Writing	Issue and Argument essays	Demonstrate command of punctuation and sentence variety.

Exam Rules

• Never join two independent clauses with just a comma.
• Use period, semicolon, or conjunction.
• Avoid overly long run-on sentences; aim for clarity.
• In formal writing, semicolons are acceptable; don’t overuse.
• Check your work for common errors before submitting.

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13. Practice Exercises

Exercise 1: Fill in the Blanks

Choose the correct punctuation or conjunction to fix each run-on or comma splice.

1. I was hungry ______ I ate an apple. (so / but / .)
2. She studied hard ______ she passed. (; / , but / .)
3. The weather was cold ______ we stayed inside. (so / . / 😉
4. He loves to travel ______ he visits new countries. (and / . / 😉
5. It was late ______ we went home. (so / . / 😉
6. The store was closed ______ we came back later. (; / , so / .)
7. I called him ______ he didn’t answer. (but / . / 😉
8. The team lost ______ they played well. (; / , but / .)
9. She was tired ______ she kept working. (yet / . / 😉
10. The movie was long ______ it was interesting. (; / , but / .)

Exercise 2: Multiple Choice Questions

Choose the correct corrected sentence.

1. Which is the correct fix for: “I like your haircut it looks really good.”
   a) I like your haircut, it looks really good.
   b) I like your haircut; it looks really good.
   c) I like your haircut it looks really good.
   d) I like your haircut, and it looks really good. (Both b and d are correct)
2. Which is a run-on sentence?
   a) The sun is shining, and it’s warm.
   b) The sun is shining it’s warm.
   c) The sun is shining; it’s warm.
   d) Because the sun is shining, it’s warm.
3. Which sentence uses a semicolon correctly?
   a) I was tired; I went to bed.
   b) I was tired; and I went to bed.
   c) I was tired, I went to bed.
   d) I was tired; and, I went to bed.
4. Which conjunction makes a compound sentence?
   a) because
   b) although
   c) so
   d) since
5. Which is a complex sentence?
   a) She was late, so she missed the train.
   b) Because she was late, she missed the train.
   c) She was late; she missed the train.
   d) She was late. She missed the train.
6. What is the FANBOYS acronym for?
   a) subordinating conjunctions
   b) coordinating conjunctions
   c) prepositions
   d) pronouns
7. Which is a comma splice?
   a) He ran, and he won.
   b) He ran, he won.
   c) He ran; he won.
   d) He ran so he won.
8. How do you fix “I was hungry I ate lunch”?
   a) I was hungry, I ate lunch.
   b) I was hungry; I ate lunch.
   c) I was hungry I ate lunch.
   d) I was hungry, and I ate lunch. (Both b and d correct)
9. Which subordinating conjunction shows time?
   a) but
   b) when
   c) so
   d) yet
10. Which sentence is punctuated correctly?
    a) The store closed, we went home.
    b) The store closed; we went home.
    c) The store closed and we went home.
    d) The store closed, so we went home. (b and d correct)

Exercise 3: Sentence Transformation / Error Correction

Rewrite each run-on or comma splice correctly using the method indicated in parentheses.

1. I was tired I slept. (Use period)
2. She sings well she dances too. (Use semicolon)
3. He studied hard he passed. (Use FANBOYS “so”)
4. It was raining we stayed home. (Use complex sentence with “because”)
5. The food was cold I ate it. (Use FANBOYS “but”)
6. They won the game they celebrated. (Use semicolon)
7. I called him he didn’t answer. (Use period)
8. The movie was long it was good. (Use “although”)
9. She was tired she kept working. (Use “yet”)
10. The store closed we left. (Use “so”)

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14. Answer Key with Explanations

Exercise 1 Answers

1. so
   Explanation: “so” connects cause and effect.
2. .
   Explanation: Period or semicolon; “so” would also work.
3. so
   Explanation: Cause and effect.
4. and
   Explanation: Adds information.
5. so
   Explanation: Result.
6. ;
   Explanation: Semicolon links related ideas.
7. but
   Explanation: Contrast.
8. , but
   Explanation: Contrast with comma + but.
9. yet
   Explanation: Contrast, more formal.
10. , but
    Explanation: Contrast.

Exercise 2 Answers

1. b) I like your haircut; it looks really good.
   Explanation: Semicolon fix.
2. b) The sun is shining it’s warm.
   Explanation: No punctuation = run-on.
3. a) I was tired; I went to bed.
   Explanation: Semicolon without conjunction.
4. c) so
   Explanation: “so” is FANBOYS.
5. b) Because she was late, she missed the train.
   Explanation: Dependent clause + independent.
6. b) coordinating conjunctions
   Explanation: FANBOYS.
7. b) He ran, he won.
   Explanation: Comma splice.
8. b) I was hungry; I ate lunch.
   Explanation: Semicolon fix. (d also correct)
9. b) when
   Explanation: Time conjunction.
10. b) The store closed; we went home.
    Explanation: Semicolon. (d also correct)

Exercise 3 Answers

1. I was tired. I slept.
   Explanation: Two separate sentences.
2. She sings well; she dances too.
   Explanation: Semicolon joins.
3. He studied hard, so he passed.
   Explanation: Comma + so.
4. Because it was raining, we stayed home.
   Explanation: Complex sentence, dependent first with comma.
5. The food was cold, but I ate it.
   Explanation: Comma + but.
6. They won the game; they celebrated.
   Explanation: Semicolon.
7. I called him. He didn’t answer.
   Explanation: Period.
8. Although the movie was long, it was good.
   Explanation: Dependent clause with “although” first.
9. She was tired, yet she kept working.
   Explanation: Comma + yet.
10. The store closed, so we left.
    Explanation: Comma + so.

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15. Conclusion

Run-on sentences and comma splices are two common but serious writing errors. The good news is that they are easy to fix with a few simple methods.

Key points to remember:

• Run-on: two sentences with no punctuation.
• Comma splice: two sentences joined with only a comma.
• Fix with: period, semicolon, FANBOYS conjunction, or subordinating conjunction.
• Period is simplest; semicolon shows sophistication; compound and complex sentences add variety.
• Always separate independent clauses correctly.

By mastering these fixes, you will improve your writing clarity, style, and exam scores. Practice regularly, and soon correct punctuation will feel natural.

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Call to Action: Review your last essay or email. Find any run-on sentences or comma splices. Rewrite them using at least two different methods from this lesson. Then, write a short paragraph about a recent event using a mix of sentence types: simple, compound, and complex. Share with a teacher or study partner for feedback.