Recognizing Run-Ons and Fragments (Basic)




Exercise Links:
Grammar Exercise #2
Grammar Exercise #3
Punctuation Exercises
Usage Exercises

Related Links:
Fragments (Purdue)
Run-Ons (Purdue)

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Writing Exercises


The sentence is the fundamental unit of expression in professional writing. To maintain credibility as a professional, you have to know what constitutes a sentence. In the exercise below, identify whether each of the highlighted word groups is a sentence (S), fragment (F), or run-on (RO). Note that a run-on is a specific grammatical term referring not to a long sentence, but to a group of words containing two or more independent clauses that are incorrectly joined. Once you have clicked on the right answer, you will view a discussion. Corresponding information for this exercise can be found in The Craft of Editing (denoted CE) and The Craft of Scientific Writing (denoted CSW). Note: In the general preferences of your browser, please do not override this document's choice of font colors.





  1. Although the shock sphere is still strong at the end of the fireball's life, the sphere is no longer strong enough to heat the air to incandescence.

    Sentence
    Fragment
    Run-On




































    Congratulations, you have answered #1 correctly.

    Original: Although the shock sphere is still strong at the end of the fireball's life, the sphere is no longer strong enough to heat the air to incandescence.

    Discussion: No grammatical mistake exists. This group of words is a sentence with an introductory dependent clause coupled to an independent clause.


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  2. At that point the shock sphere is no longer strong enough to heat the air to incandescence, however, the sphere is still very strong.

    Sentence
    Fragment
    Run-On




































    Congratulations, you have answered #2 correctly.

    Original: At that point the shock sphere is no longer strong enough to heat the air to incandescence, however, the sphere is still very strong.

    Revision: At that point, the shock sphere is no longer strong enough to heat the air to incandescence. However, the sphere is very strong.

    Discussion: The original was a run-on. The adverb "however" cannot join two independent clauses. Note that several ways exist to correct this run-on. Also note that beginning a sentence with "however" is not an error. More discussion exists in CE (pages 115 and 129) and CSW (259, 270).


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  3. At the end of the fireball's life, the shock sphere no longer being strong enough to heat the air to incandescence.

    Sentence
    Fragment
    Run-On





































    Congratulations, you have answered #3 correctly.

    Original: At the end of the fireball's life, the shock sphere no longer being strong enough to heat the air to incandescence.

    Revision: At the end of the fireball's life, the shock sphere is no longer strong enough to heat the air to incandescence.

    Discussion: The original was a fragment without a verb. The verb "is" makes this group of words a sentence. More discussion exists in CE (page 111).


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  4. Both sites produce the same three sources of energy: coal, oil, and natural gas. Both sites, however, do not produce these sources in the same proportions.

    Sentence
    Fragment
    Run-On





































    Congratulations, you have answered #4 correctly.

    Original: Both sites produce the same three sources of energy: coal, oil, and natural gas. Both sites, however, do not produce these sources in the same proportions.

    Discussion: No grammatical mistake exists. The first sentence is a simple independent clause that introduces a list, and the second sentence is a simple independent clause with the adverb "however" inserted as a parenthetical between the subject and the verb.


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  5. The plant shutdown was more than just another company having to close its doors, Bolens was a way of life for hundreds of families in the small town where the company was located.

    Sentence
    Fragment
    Run-On





































    Congratulations, you have answered #5 correctly.

    Original: The plant shutdown was more than just another company having to close its doors, Bolens was a way of life for hundreds of families in the small town where the company was located.

    Revision: The plant shutdown was more than just another company having to close its doors--Bolens was a way of life for hundreds of families in the small town where the company was located.

    Discussion: The original was a run-on. While such a run-on is allowed in informal writing, it is not accepted in formal writing. Although several ways, including a semicolon, exist to join these two independent clauses, the em-dash perhaps works best to show their relationship. More discussion exists in CE (pages 106, 130).


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  6. Both designs produce the same three pollutants (nitrogen oxides, sulfur dioxides, and hydrocarbons) in roughly the same proportions, therefore, both designs have similar effects on the environment.

    Sentence
    Fragment
    Run-On





































    Congratulations, you have answered #6 correctly.

    Original: Both designs produce the same three pollutants (nitrogen oxides, sulfur dioxides, and hydrocarbons) in roughly the same proportions, therefore, both designs have similar effects on the environment.

    Revision: Both designs produce the same three pollutants (nitrogen oxides, sulfur dioxides, and hydrocarbons) in roughly the same proportions. Therefore, both designs have similar effects on the environment.

    Discussion: The original was a run-on. The adverb "therefore" cannot join two independent clauses. More discussion exists in CE (pages 115 and 129) and CSW (259, 270).


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  7. Because both designs produce the same three pollutants (nitrogen oxides, sulfur dioxides, and hydrocarbons) in roughly the same proportions, both designs have similar effects on the environment.

    Sentence
    Fragment
    Run-On





































    Congratulations, you have answered #7 correctly.

    Original: Because both designs produce the same three pollutants (nitrogen oxides, sulfur dioxides, and hydrocarbons) in roughly the same proportions, both designs have similar effects on the environment.

    Discussion: No grammatical mistake exists. This group of words is a sentence with an introductory dependent clause coupled to an independent clause.


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  8. An oval shape is necessary in the die cavity, otherwise, the flow of metal from the hammering would be restricted.

    Sentence
    Fragment
    Run-On





































    Congratulations, you have answered #8 correctly.

    Original: An oval shape is necessary in the die cavity, otherwise, the flow of metal from the hammering would be restricted.

    Revision: An oval shape is necessary in the die cavity; otherwise, the flow of metal from the hammering would be restricted.

    Discussion: The original group of words was a run-on. Because the word "otherwise" is not a coordinating conjunction, it cannot join two independent clauses. More discussion exists in CE (pages 115 and 129) and CSW (259, 270).


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  9. Not only does fresh ventilation reduce moisture levels in animal pens, but it also improves the health and longevity of livestock.

    Sentence
    Fragment
    Run-On





































    Congratulations, you have answered #9 correctly.

    Original: Not only does fresh ventilation reduce moisture levels in animal pens, but it also improves the health and longevity of livestock.

    Discussion: No grammatical mistake exists. Because the word "but" is a coordinating conjunction, it can join two independent clauses.


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  10. Primary bodies are those that are outside the zone of protection, thus, they are susceptible to the effects of a direct lightning stroke.

    Sentence
    Fragment
    Run-On




































Congratulations, you have answered #10 correctly.

Original: Primary bodies are those that are outside the zone of protection, thus, they are susceptible to the effects of a direct lightning stroke.

Revision: Primary bodies are those that are outside the zone of protection. Thus, they are susceptible to the effects of a direct lightning stroke.

Discussion: The original was a run-on. The adverb "thus" cannot join two independent clauses. More discussion exists in CE (pages 115 and 129) and CSW (259, 270).








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Last updated 2/99
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