1. Sentence fragments
Make sure each word group you have punctuated as a sentence contains a grammatically complete and independent thought that can stand alone as an acceptable sentence, also known as an “independent clause.”
Incorrect
Tests of the Shroud of Turin have produced some curious findings. For example, the pollen of forty-eight plants native to Europe and the Middle East.
[2nd sentence = fragment]
Correct
Tests of the Shroud of Turin have produced some curious findings. For example, the cloth contains the pollen of forty-eight plants native to Europe and the Middle East.
Incorrect
Scientists report no human deaths due to excessive caffeine consumption. Although, caffeine does cause convulsions and death in certain animals.
[2nd sentence = fragment]
Correct
Scientists report no human deaths due to excessive caffeine consumption although caffeine does cause convulsions and death in certain animals.
2. Misplaced and dangling modifiers
A modifier is a word, phrase, or clause that describes another word, phrase, or clause in a sentence. Place modifiers near the words they describe; be sure the modified words actually appear in the sentence.
Incorrect
When writing a proposal, an original task is set for research. [who is writing the proposal?]
Correct
When writing a proposal, a scholar sets an original task for research.
Incorrect
Many tourists visit Arlington National Cemetery, where veterans and military personnel are buried every day from 9:00 a.m. until 5:00 p.m. [sounds as if people are being buried there everyday between 9:00 and 5:00)
Correct
Every day from 9:00 a.m. until 5:00 p.m., many tourists visit Arlington National Cemetery, where veterans and military personnel are buried.
3. Faulty parallelism
Be sure you use grammatically equal sentence elements–words, phrases, clauses–to express two or more matching ideas or items in a series.
Incorrect
The candidate’s goals include winning the election, a national health program, and the educational system.
Correct
The candidate’s goals include winning the election, enacting a national health program, and improving the educational system.
Incorrect
Some critics are not so much opposed to capital punishment as postponing it for so long.
Correct
Some critics are not so much opposed to capital punishment as they are to postponing it for so long.
4. Unclear pronoun reference
All pronouns must clearly refer to definite referents [nouns]. Use it, they, this, that, these, those, and which carefully to prevent confusion.
Unclear:
Einstein was a brilliant mathematician. This is how he was able to explain the universe.
Clear:
Einstein, a brilliant mathematician, used his ability with numbers to explain the universe.
Unclear:
Because Senator Martin is less interested in the environment than in economic development, he sometimes neglects it.
Clear:
Because of his interest in economic development, Senator Martin sometimes neglects the environment.
5. Incorrect pronoun case
Determine whether the pronoun is being used as a subject, or an object, or a possessive in the sentence, and select the pronoun form to match.
Incorrect:
Castro’s communist principles inevitably led to an ideological conflict between he and President Kennedy.
Correct:
Castro’s communist principles inevitably led to an ideological conflict between him and President Kennedy.
Incorrect:
Because strict constructionists recommend fidelity to the Constitution as written, no one objects more than them to judicial reinterpretation.
Correct:
Because strict constructionists recommend fidelity to the Constitution as written, no one objects more than they [do] to judicial reinterpretation.
6. Omitted commas
Use commas to signal nonrestrictive or nonessential material, to prevent confusion, and to indicate relationships among ideas and sentence parts.
Incorrect:
When it comes to eating people differ in their tastes.
Correct:
When it comes to eating, people differ in their tastes.
Incorrect:
The Huns who were Mongolian invaded Gaul in 451.
Correct:
The Huns, who were Mongolian, invaded Gaul in 451.
[“Who were Mongolian” adds information but does not change the core meaning of the sentence because Huns were a Mongolian people; this material is therefore nonrestrictive or nonessential.]
7. Superfluous commas
Unnecessary commas make sentences difficult to read.
Unclear:
Field trips are required, in several courses, such as, botany and geology.
Clear:
Field trips are required in several courses, such as botany and geology.
Unclear:
The term, “scientific illiteracy,” has become almost a cliche, in educational circles.
Clear:
The term “scientific illiteracy” has become almost a cliche in educational circles.
8. Comma splices
Comma splices link two independent clauses or complete sentences with a comma. Instead, use a period or semicolon, or rewrite the sentence.
Comma splice:
In 1952 Japan’s gross national product was one third that of France, by the late 1970s it was larger than the GNPs of France and Britain combined.
Correct:
In 1952 Japan’s gross national product was one third that of France. By the late 1970s it was larger than the GNPs of France and Britain combined.
Comma splice:
Diseased coronary arteries are often surgically bypassed, however half of all bypass grafts fail within ten years.
Correct:
Diseased coronary arteries are often surgically bypassed; however, half of all bypass grafts fail within ten years.
9. Run-on Sentences
A run-on sentence is not a long sentence. A sentence can be half a page long and be correct. A run-on or fused sentence is when two complete sentences are joined without any punctuation or transitions. Run-on sentences can be especially confusing because the reader won’t know the relationship between the two sentences.
Incorrect: The forecast calls for rain our picnic is canceled.
Correct: The forecast calls for rain; our picnic is canceled. OR The forecast calls for rain, so our picnic is canceled. OR The forecast calls for rain; therefore, our picnic is canceled.
Incorrect: Take a moment to relax you’ll feel better.
Correct: Take a moment to relax; you’ll feel better. OR Take a moment to relax, and you’ll feel better. OR Taking a moment to relax will make you feel better.
10. Apostrophe Errors
Apostrophes indicate possession for nouns (“Jim’s hat,” “several years’ work”) but not for personal pronouns (its, your, their, and whose). Apostrophes also indicate omissions in contractions (“it’s” = “it is”). In general, they are not used to indicate plurals.
Incorrect:
In the current conflict its uncertain who’s borders their contesting.
Correct:
In the current conflict it is [it’s] uncertain whose borders they are [they’re] contesting.
Incorrect:
The Aztecs ritual’s of renewal increased in frequency over the course of time.
Correct:
The Aztecs’ rituals of renewal increased in frequency over the course of time.
11. Words easily confused
“Effect” is most often a noun (the effect), and “affect” is almost always a verb. Other pairs commonly confused: “lead”/”led” and “accept”/”except.” Check a glossary of usage to find the right choice.
Incorrect:
The recession had a negative affect on sales.
Correct:
The recession had a negative effect on sales.
(or) The recession affected sales negatively.
Incorrect:
The laboratory instructor chose not to offer detailed advise.
Correct:
The laboratory instructor chose not to offer detailed advice.
12. Misspellings
Spelling errors are usually perceived as a reflection of the writer’s careless attitude toward the whole project. Don’t allow your hard work to be marred in this way! In addition to comprehensive dictionaries, use electronic spell checks, spelling dictionaries, and lists of frequently misspelled words found in handbooks.