Faulty Sentence Structure
What it is:
Faulty sentence structure is one of the most common grammar mistakes. Faulty sentence structure includes comma splices, run-ons, and fragments. These mistakes directly affect clarity and readability by making your ideas hard to follow or grammatically incomplete. Readers may have to re-read your sentences to understand your point, which reduces the impact of your argument and can lower your essay score.
Examples:
Comma Splice:
We had a good time, we played softball.
✅ We had a good time and played softball.
Run-On Sentence
I finished my homework I went to sleep.
✅ I finished my homework, and then I went to sleep.
How to avoid it:
- Ensure each sentence has a subject and a verb.
- Use conjunctions (and, but, because) or punctuation to join independent clauses.
- Read your work aloud to hear where natural breaks should occur.
Incomplete or Missing Documentation
What it is:
If you’re working on a research project or an essay that relies on outside sources to strengthen your arguments, you know how important it is to cite every resource you use properly. Failing to give credit, whether by missing in-text citations, omitting a works cited page, or including incomplete source details, is a serious academic mistake. It can lead to plagiarism, which carries significant consequences for your academic performance and reputation.
Example:
According to Smith, “climate change is accelerating.”
✅ According to Smith, “climate change is accelerating” (Smith, 2023). (MLA Style)
✅ According to Smith (2023), “climate change is accelerating,” or “Climate change is accelerating” (Smith, 2023). (APA Style)
How to avoid it:
- Keep detailed notes on all your sources as you research.
- Use citation tools like EasyBib, Zotero, or built-in citation generators.
- Double-check your formatting for MLA, APA, or Chicago style before submitting.
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Overuse of Passive Voice
What it is:
Passive voice hides the subject and makes writing sound weak or indirect. Overuse of passive voice can make your argument feel vague and reduce your credibility.
Example:
The essay was written by the student.
✅ The student wrote the essay.
How to avoid it:
- Identify the subject and verb: who is doing what?
- Make the subject perform the action when possible.
Vague Pronoun Reference
What it is:
Vague pronouns happen when your reader can’t tell which noun a pronoun replaces. This confuses the meaning you want to deliver, which is especially damaging when you’re trying to make a precise argument.
Example:
When John met Steve, he was excited.
✅ When John met Steve, John was excited.
How to avoid it:
- Make sure each “it,” “this,” “that,” “he,” or “they” has a clear, specific noun it refers to.
- Replace the pronoun with the noun if the reference is unclear.
Missing Comma in a Compound Sentence
What it is:
A missing comma in a compound sentence happens when you connect two complete thoughts with “and,” “but,” or another coordinating conjunction, but forget the comma before the conjunction. This small error can change the flow and clarity of your writing.
Example:
I studied for the exam but I still felt nervous.
✅ I studied for the exam, but I still felt nervous.
How to avoid it:
- Remember FANBOYS (For, And, Nor, But, Or, Yet, So): these can be used as a signal to let you know you need to use a comma.
- Place a comma before these conjunctions when connecting two complete sentences.
Misplaced Modifiers
What it is:
A misplaced modifier is when a descriptive word or phrase is too far from the word it’s meant to describe. This can confuse your reader or change the meaning of your sentence entirely.
Example:
Reading in low light slowly gives me a headache.
✅ Reading slowly in low light gives me a headache.
How to avoid it:
- Place modifiers right next to the words they describe.
- Read your sentence aloud: if it sounds confusing, it probably needs rearranging.
Sentence Fragments
What it is:
Sentence fragments are incomplete sentences presented as complete thoughts. Fragments usually lack a subject, verb, or both. They can make your essay feel unfinished or sloppy.
Example:
Because I wanted to get a good grade.
✅ I studied hard because I wanted to get a good grade.
How to avoid it:
- Each sentence must stand alone with a subject and a verb.
- Join fragments to complete sentences if they depend on context.
Misuse of Contractions and Apostrophes
What it is:
Mixing up words like “it’s” vs “its” or “you’re” vs “your” is extremely common. These mistakes look careless and will distract readers from your ideas.
Example:
Its a beautiful day outside.
✅ It’s a beautiful day outside.
How to avoid it:
- Remember quick rules: It’s = “it is” or “it has” | Its = possessive | You’re = “you are” | Your = possessive.
- Expand the word in your head. If “it is” works, use “it’s.”
- Proofread carefully for homophones.
Spelling Errors
What it is:
Spelling mistakes are disruptive and make your work look careless. They can even change the meaning of your sentence if you accidentally use the wrong word.
Example:
The goverment should adress this issue.
✅ The government should address this issue.
How to avoid it:
- Use spellcheck tools
- Trace your pencil under each line and read carefully to identify mistakes
- Read your work backward (from the end to the beginning) to check for spelling mistakes
Unnecessary or Missing Capitalization
What it is:
Students often capitalize words that shouldn’t be capitalized or forget to capitalize proper nouns. This makes your writing look unprofessional.
Example:
She will attend Harvard university next fall.
✅ She will attend Harvard University next fall.
How to avoid it:
- Proper nouns (names of people, places, organizations) are capitalized.
- The first word of every sentence is capitalized.
- Common nouns are kept lowercase.
Unnecessary Comma
What it is:
Putting commas where they don’t belong interrupts the natural flow of your writing, which can confuse your reader or make your sentence grammatically incorrect.
Example:
My brother, plays the guitar.
✅ My brother plays the guitar.
How to avoid it:
- Don’t put a comma between a subject and a verb.
- Read your writing aloud to find unnatural pauses.
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Missing or Unnecessary Hyphen
What it is:
Students often forget hyphens in compound adjectives (such as “well-written essay”) or add them where they don’t belong, which can create confusion about which words go together.
Example:
This is a well written essay.
✅ This is a well-written essay.
How to avoid it:
- Hyphenate compound adjectives before nouns.
- Do not hyphenate when the first word is an “-ly” adverb.
The Overuse of Adverbs
What it is:
Many students rely too much on vague adverbs like “really,” “very,” or “extremely” to meet word counts or emphasize ideas. Overusing adverbs weakens your writing and can make you sound less confident.
Example:
She was really tired after the game.
✅ She was exhausted after the game.
How to avoid it:
- Use precise, vivid verbs and adjectives instead.
- When editing, remove adverbs that don’t add necessary detail.
These common grammar mistakes can easily slip into your high school essays. However, by learning to identify and correct them, your writing will become more precise, clear, and impactful. For additional support, you can use this proofreading guide from Purdue OWL to strengthen your editing process and catch errors before submitting your essays.
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