It’s important to always form complete sentences in our writing. However, it can be easy to write incomplete sentence fragments, or long run-on sentences without realizing it.
English Grammar: Incomplete Sentences
In English grammar, a sentence must have a subject, a verb, and an object. The subject creates the action, the verb is the action, and the object receives the action. At times an object can be implied.
For example, “There are many varieties of apples. Like Macintosh, Rome and Red Delicious.” The first sentence is complete. The second is an incomplete fragment. This is easily corrected.
“There are many varieties of apples, like Macintosh, Rome and Red Delicious.”
If the sentence becomes more complicated and involved, it can become easy to miss a the fact that it’s incomplete. Just check your sentence to see if it has a subject, a verb and an object.
“There was an early frost that year. Causing the apple trees to lose their blossoms, and ruining the whole crop.” Since the second incomplete sentence fragment is longer and more involved, it almost seems like a complete sentence. But if you look at it closely, you’ll see that it contains no subject or verb. The entire sentence is constructed entirely of dependent clauses. This sentence is easily corrected.
“There was an early frost that year, causing the apple trees to lose their blossoms, and ruining the whole crop.”
If you wish to use an incomplete sentence fragment to make a point, always put it in quotes. This separates the fragment from the rest of the document, and makes it clear that you’re using it as an example.
English Grammar: Run-On Sentences
Run-on sentences are a common English grammar error. A run-on sentence tacks several sentences together, as though they were one unit.
For example, “I went to the drug store to pick up some pain reliever, and I ran into Doug, who told me his wife was pregnant, and that she had edema, and the doctor had told her to stay in bed, so I said I was sorry she was having a hard time, and told Doug to give her my best wishes.”
This is a run-on sentence. Here’s a good correction.
“I went to the drug store to pick up some pain reliever. I ran into Doug, who told me his wife was pregnant. He said she had edema, and the doctor told had her to stay in bed. So I said I was sorry she was having a hard time, and told Doug to give her my best wishes.”
The long, run-on sentence here has been divided up into four sentences of reasonable length. Note here that words such as “so,” “and,” and “but” can be used to begin a sentence, as long as it’s complete. The practice has become more accepted over time, and is often permitted even in moderately formal writing. I believe this is because there are times when you simply can’t phrase your thoughts another way. The alternatives can often seem stilted or excessively formal, which can hurt the point you’re trying to make.
For example, if you’re writing an article about cooking or crafts, beginning a sentence with a conjunction is probably acceptable. However, if you’re writing an extremely important news article, or writing for a medical journal, you should most likely use the more proper and formal forms.
For example, “The drug Paxil has been associated with birth defects. Additionally, many patients who used this drug experienced negative side effects.”
The word additionally helps to get your point across, while maintaining your intended formal tone.
Use your best judgment. When in doubt, check references, such as a dictionary or English grammar books.