How to identify and revise 20 common grammatical errors
Roberto Rivera BA
Corresponding author: Roberto Rivera
Contact Information: Roberto.email@example.com
Crafting any piece of academic or professional writing calls for clarity, which can pose many challenges to novice and seasoned writers alike.1 One area that many writers find difficult is correct grammar and usage. Most writers are familiar with basic grammar; however, many types of writing errors can be difficult to detect.2 Despite peer review and word processing tools, some errors can persist due to incomplete knowledge of grammatical norms, punctuation, and vocabulary. This article will review twenty common grammatical errors and some strategies for addressing them.3 The following section will include examples in which the first sentence (A) will be incorrect, which will then be followed by a revised sentence (B).
1. Wrong word
There might be times during which writers may want to use vocabulary without a full understanding of specific words. Writers may sometimes use words that have the wrong meaning, the wrong shade of meaning, or the wrong preposition or idiom. An easy strategy is to not use words that are unfamiliar, or to use an online dictionary as a quick reference.1
- Many drugs in this class have adverse affects.
- Many drugs in this class have adverse effects.
- Aliquots of venous blood were collected 4 times.
- Samples of venous blood were collected 4 times.
2. Missing comma after introductory element
Commas can be used to represent a pause that would be present in regular speech. Common introductory elements include introductory words, phrases, and clauses.
- After exercise most athletes stretch their muscles.
- After exercise, most athletes stretch their muscles.
- Conversely eggs can be hardboiled.
- Conversely, eggs can be hardboiled.
3. Incomplete or missing documentation
Each piece of quote, citation, or evidence should be referenced correctly to avoid plagiarism. To avoid any charges of academic theft, be sure to cite quotations and borrowed ideas, to enclose borrowed language in quotation marks, and to put summaries and paraphrases in your own words. The best strategy is to follow style guidelines as closely as possible, and include as much relevant information as possible.4
4. Vague pronoun reference
Pronouns are helpful tools that take the place of a noun. Writers sometimes run into trouble when there is an unclear antecedent. When there are multiple nouns being referenced, the writer can replace the pronoun with the intended subject
- Although the car hit the wall, it was not damaged.
- Although the car hit the wall, the wall was not damaged.
- If you put this chart in your journal, you can refer to it.
- If you put this chart in your journal, you can refer to the chart.
Correct spelling has become less of a problem with modern word processing tools. However, homonyms, compound words, and proper nouns can evade spell checkers. Writers can supplement their spell checkers by brushing up on their vocabulary. Many online dictionaries and phone applications provide a “word of the day” feature that can be helpful.
- Adverbs compliment verbs to provide additional information.
- Adverbs complement verbs to provide additional information.
- I scent the package by mail.
- I sent the package by mail.
6. Quotation mechanics
Always follow style guidelines for using quotation marks correctly. There are many scenarios that require quotation marks, such as dialogue or citations. There are many examples and exercises available online that can be referenced for quick fixes.
- Ultimately, my doctor told me “I want to see you in a month”.
- Ultimately, my doctor told me, “I want to see you in a month.”
7. Unnecessary commas
Some commas may appear in incorrect places. Commas are not needed before conjunctions in sentences with compound subjects or verbs. Additionally, commas don’t need to surround restrictive elements of a sentence. A restrictive element is a part of a sentence that is necessary to keep the meaning of the sentence.4 In other words, if the restrictive element is removed, then the main idea of the sentence changes.
- The student opened her book, and drank her coffee.
- The student opened her book and drank her coffee.
- The counselor, who worked the case, provided relevant information.
- The counselor who worked the case provided relevant information.
8. Unnecessary or missing capitalization
Capitalization often comes down to mechanics. In general, proper nouns, titles of works, and abbreviations are capitalized. There are many guidelines available online that can help writers know when and when not to capitalize. In addition to guidelines, a good dictionary can provide more direction. Also, English can be a very fluid language, as norms can shift over time. For example, terms like the E-mail and World Wide Web used to be capitalized but are no longer in contemporary use.3
- The students are preparing for their Nursing board exams.
- The students are preparing for their nursing board exams.
- Our Company the right stuff focuses on home improvement tools.
- Our company The Right Stuff focuses on home improvement tools.
9. Missing word
A simple oversight can result in a missing word. A spell checker may not catch a missing word, which can alter the intended meaning of a sentence. One strategy is to read the paper aloud in an empty room or to a colleague. Listening to the text provides another perspective that can highlight simple errors like a missing word.
- Corn is planted on a basis.
- Corn is planted on a yearly basis.
10. Faulty sentence structure
Writers may feel pressure to add variety or complexity to their writing not realizing that he or she may be sacrificing clarity. A good method to identify faulty structures is for the writer to read the paper out loud. Passages that sound confusing may have an underlying issue with structure. Some possible examples include redundancies, unbalanced parallel ideas, and shifts in points of view.
- In anatomy, our small group dissected a cadaver together. You were graded on how well you isolated structures.
- In anatomy, our small group dissected a cadaver together. We were graded on how well we isolated structures.
- My friend’s car needs an oil change, fill up on gas, and new wipers.
- My friend’s car needs an oil change, gas, and new wipers.
11. Missing comma with non-restrictive elements
In contrast with restrictive elements, non-restrictive elements only provide additional information. Writers can perform a “removal test,” where a phrase or element in question can be removed. If the removal does not alter the intended meaning of a sentence, then it is nonessential and requires commas surrounding it.
- Providers’ documentation, that contains sensitive information, must be kept confidential.
- Providers’ documentation that contains sensitive information must be kept confidential.
12. Unnecessary shift in verb tense
Verb tenses play an important role in setting the temporal framework of a story or passage. Sudden shifts in verb tense can be jarring to a reader because the temporal framework has been confused. In general, writers can avoid this situation by being consistent in their verb tenses, especially within the same sentence.
- The pitcher will throw the ball, then the batter swung the bat.
- The pitcher will throw the ball, then the batter will swing the bat.
13. Missing comma in a compound sentence
In contrast to simple sentences with compound subjects or verbs, commas are necessary before a coordinating conjunction that joins two independent clauses. These are easily remembered by the mnemonic FANBOYS: for, and, not, but, or, yet, and so.
- My phone’s battery died so I ordered a new battery.
- My phone’s battery died, so I ordered a new battery.
14. Unnecessary or missing apostrophe
Apostrophes are used to indicate possession and contractions. A problematic contraction is “it’s,” which is commonly confused with “its.” The contraction stands for “it is,” while “its” is a possessive pronoun like “his” or “her.” It may be helpful to avoid contractions while writing. Writers can potentially catch errors by reading their work out loud.
- My dog brings me it’s leash before a walk.
- My dog brings me its leash before a walk.
- Both shoes’s laces had broken.
- Both shoes’ laces had broken.
15. Fused (Run-on) sentence
Fused sentences are two complete sentences that have been weakly joined. These instances can be resolved by using stronger punctuation like a coordinating conjunction, period, or semi-colon.
- A carpenter marks his cuts with pencil he uses a table saw for precise angles.
- A carpenter marks his cuts with pencil, and he uses a table saw for precise angles.
16. Comma splice
A comma splice is a common type of fused sentence. Here, two independent sentences are weakly joined by a comma. Adding a coordinating conjunction or using a period to separate the two sentences can correct the comma splice.
- The cough started Wednesday, he says it has been getting worse.
- The cough started Wednesday. He says it has been getting worse.
17. Lack of pronoun-antecedent agreement
In addition to having a clear antecedent, pronouns must agree with the referenced noun in number, gender, and type. Inconsistency creates confusion, so writers should make sure their pronouns match the referred noun.
- A mother duck leads their family across the road.
- A mother duck leads her family across the road.
18. Poorly integrated quotations
Quotations and evidence should be integrated smoothly into the surrounding sentence structure. Abrupt deployment of quotes can mask the writer’s main message, which can create confusion for the reader. One strategy is to use signal phrases to introduce evidence, and then follow it with an explanatory sentence.
- Childhood obesity has increasingly received national attention regarding consumption of sugary beverages. “80% of children’s diets include six cans of soda a day” (Smith, 1989).
- Childhood obesity has increasingly received national attention regarding consumption of sugary beverages. John Smith, director of nutrition at X Institute, notes that “80% of children’s diets include six cans of soda a day” (1989).
19. Unnecessary or missing hyphen
Hyphenation can be difficult because it can be very dependent on the situation. Compound words may or may not be hyphenated, and a dictionary will be helpful. If a compound word does not appear in a dictionary, then the writer should treat it as two words.4 Compound adjectives should be hyphenated if they come before the noun they modify. If the compound adjective follows the noun, then it does not get hyphenated. Also, hyphens should not be used to connect an adverb ending in –ly to an adjective.
- My daughter tried to cross examine the family dog.
- My daughter tried to cross-examine the family dog.
- John is a well regarded athlete.
- John is a well-regarded athlete.
20. Sentence fragments
Fragments are sentences that are missing a subject or a verb. Because the sentences are incomplete, the fragments depend on another sentence for its meaning. One strategy for finding sentence fragments in a draft is to read the paper aloud sentence by sentence. The fragments can be revised by completing the sentence with a subject or verb, or it can be joined to an adjacent sentence with proper punctuation.
- The punter kicks the ball. Caught by the receiving team.
- The punter kicks the ball; then it is caught by the receiving team.
- The book’s spine has cracked. Showing years of steady use.
- The book’s spine has cracked, showing years of steady use.
While these errors can be difficult to detect during the writing process, they have easy and quick fixes. Learning about common errors and respective solutions, writers can be more mindful and recognize errors more quickly. Additionally, developing a few strategies can be very valuable. Reading a paper aloud, using writing guidelines available online, and consulting a good dictionary are three great habits that will reduce errors and improve clarity.
Key words: scientific writing, grammar, punctuation
- Messuri K. Clarity in medical writing. Southwest Respir Crit Care Chron 2015; 3 (12): 56-58.
- Messuri K. Revision strategies. Southwest Respir Crit Care Chron 2016; 4 (14): 46-48.
- Roy D, lecturer. Top 20 grammatical errors and how to fix them [Lecture]. Lubbock (TX): TTUHSC Writing Center; 2016.
- Hacker D, Sommers N. A pocket style manual. 7th ed. Boston (MA): Bedford/St. Martin’s, 2015.
Author affiliation: Texas Tech University Health Sciences Center in Lubbock, TX
Conflicts of interest: none
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