A run-on sentence is two or more sentences written incorrectly as one sentence. Sentences cannot be correctly written with only a comma between the sentences or with no punctuation between.
Nothing is all dark, there cannot be a picture without its bright spots. (run-on—only a comma between sentences. This error is often called a comma splice.)
Nothing is all dark there cannot be a picture without its bright spots. (run-on—no punctuation between sentences. This error is often called & fused sentence.)
Nothing is all dark. There cannot be a picture without its bright spots. (corrected)
Run-on sentences may be corrected in the following ways:
a. If the sentences contain separate and distinct ideas, use a period and a capital letter.
There are very few who will admit a mistake, such obstinacy is a barrier to all improvement. (run-on)
There are very few who will admit a mistake. Such obstinacy is a barrier to all improvement. (corrected)
b. If the ideas in the sentences are so closely related as to form one thought and are equally important, use a comma and coordinating conjunction (and, but, or, nor, for, yet).
Take time to deliberate, lose no time in executing your resolutions. (run-on)
Take time to deliberate, but lose no time in executing your resolutions.(corrected)
c. If the ideas in the sentences are so closely related as to form one thought and are equally important, you may use a semicolon instead of the comma and coordinating conjunction.
God will prune His people but not hew them down, the right hand of His mercy knows what the left hand of His severity is doing. (run-on)
God will prune His people but not hew them down; the right hand of His mercy knows what the left hand of His severity is doing. (corrected)
d. If the ideas in the sentences are so closely related as to form one thought but are not equally important, you should subordinate the less important sentence; that is, make the less important sentence into a dependent (subordinate) clause.
A man’s temper gets the best of him, it reveals the worst of him. (run-on)
When a man’s temper gets the best of him, it reveals the worst of him. (corrected)
Unity means oneness—oneness of thought and of purpose. In order for a sentence to have unity
(1) its statements must be closely related
(2) the relationship of its statements must be clear
(3) the statements must compose only one thought
Do not put unrelated ideas into the same sentence. If the ideas are not closely related, make them separate sentences. If the ideas are not related at all, eliminate one of them.
Alexander Graham Bell invented the telephone, and his invention was the result of many years of scientific study. (The ideas are not closely related.)
Alexander Graham Bell invented the telephone. His invention was the result of many years of scientific study. (correct)
Make sure the relationship between ideas is immediately clear.
We were going to school, and we saw a possum. (relationship not clear)
As we were going to school, we saw a possum. (relationship of time, now clear)
They wanted to maintain good health, and they started an exercise program. (relationship not clear)
To maintain good health, they started an exercise program. (relationship of purpose, now clear)
The length of a sentence does not necessarily affect its unity. A very long sentence may have unity, whereas a short sentence may not.
If we resort for a criterion to the different principles on which different forms of government are established, we may define a republic to be, or at least may bestow that name on, a government which derives all its powers directly or indirectly from the great body of the people, and is administered by persons holding their offices during pleasure, for a limited period, or during good behavior. — James Madison
(Although this sentence contains sixty-eight words, it has unity because its ideas exhibit a oneness of thought and purpose.)
