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Handout created by Haley D. Anderson
Compound Sentences
A complete sentence has one subject, one verb, and any necessary direct or indirect objects. To
properly join two complete sentences you must use a comma and conjunction, a semicolon, or a
semicolon with a conjunctive adverb.
● There are three common mistakes people make when combining sentences:
1) It is incorrect to combine two complete sentences with only a
conjunction. This creates a run-on sentence.
○ Incorrect: Sue was late to class and the teacher was upset.
○ This example is incorrect because “Sue was late to class” and “the
teacher was upset” are two complete sentences combined with nothing more
than a conjunction (and).
○ To correct this sentence, add a comma before the conjunction: “Sue
was late to class, and the teacher was upset.”
2) It is incorrect to combine two complete sentences with only a comma. This
creates a comma splice.
○ Incorrect: Sue arrived late, the teacher punished her.
○ This example is incorrect because “Sue arrived late” and “the teacher
punished her” are two complete sentences combined with nothing more than a
comma.
○ To correct this sentence, add a conjunction after the comma: “Sue
arrived late, so the teacher punished her.” Alternatively, replace the comma with
a semicolon: “Sue arrived late; the teacher punished her.”
3) It is incorrect to join two complete sentences with no punctuation or conjunction. This
creates a fused sentence.
○ Incorrect: Sue ran into the classroom out of breath she was very late.
○ This example is incorrect because “Sue ran into the classroom out of
breath” and “she was very late” are two complete sentences combined with
nothing.
○ To correct this sentence, add a comma and conjunction after the first
sentence: “Sue ran into the classroom out of breath, for she was very late.”
Alternatively, add a semicolon after the first sentence: “Sue ran into the
classroom out of breath; she was very late.”
Combining Sentences Using Commas and Conjunctions
● Commas can be used with a conjunction to join two complete sentences and create a compound
sentence.
● To combine sentences this way, use the comma after the first complete sentence, then follow it
with a suitable conjunction.
● There are seven conjunctions that can be used with the comma: and, but, yet, if, or, nor, for.
● Exercise A - Correct these sentences using commas and/or conjunctions where appropriate.
Indicate whether the sentence was a run-on, comma splice, or fused sentence.1
1) Betsy is a very thoughtless girl, her brother always complains about her.
2) The dog barked all night it was very irritating.
3) The tree fell on the house and the roof caved in.
4) It was summer the playground was empty.
5) My boyfriend made me very upset, I cried all night.
6) Christine fought long and hard but at last the disease overpowered her.
Combining Sentences Using Semicolons
● Semicolons can be used to join two complete sentences in two ways:
1) Without a conjunction or connecting word
○ Incorrect: Whenever it rains; I feel depressed
○ Correct: The painting was very pretty; it was destroyed in the war.
○ The first example is incorrect because the first part of the sentence is not a
complete sentence.
○ The second example is correct because both parts are complete sentences, so they
can be connected with a semicolon.
2) Using a conjunctive adverb followed by a comma, such as therefore, moreover,
furthermore, accordingly, nevertheless, however, etc.
○ Incorrect: The painting was very pretty; but it was destroyed in the war.
○ Correct: The painting was very pretty; however, it was destroyed in the war.
○ The first example is incorrect because the connecting word being used is a simple
conjunction, not a conjunctive adverb.
○ The second example is correct because the semicolon is followed by a conjunctive
adverb (however) and a comma.
● Exercise B - Correct these sentences using semicolons where appropriate. If a conjunctive
adverb was used put in a comma where needed as well. Indicate whether the
sentence was a run-on, comma splice, or fused sentence.2
1) Tim had a great desire to learn Spanish therefore he enrolled in a language school.
2) The farmers argued over who owned the field, the judge had to decide the case in the
end.
3) The wind blew hard that night the cattle got loose when the fence collapsed.
4) The marathon was not a long one however Jesse did not account for the bad weather.
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Answers to Exercise A: 1) conjunction after the comma, comma splice 2) comma and conjunction after night, fused 3)
comma after house, run-on 4) comma and conjunction after summer, fused 5) conjunction after the comma, comma
splice 6) comma after hard, run-on
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Answers to Exercise B: 1) semicolon after Spanish, comma after therefore, run-on 2) replace comma with a semicolon,
comma splice 3) semicolon after night, fused 4) semicolon after one, comma after however, run-on