10 Grammar Rules Students Break Most (And How to Fix Them)
Academic writing is unforgiving. A well-researched essay can lose an entire grade tier because of consistent grammar errors that signal carelessness to professors and markers. Here are the 10 rules most students break — and exactly how to fix them before submission.
1. Comma Splices
Joining two independent clauses with just a comma is a comma splice. "I studied all night, I still failed the exam" is wrong. Fix it with a semicolon ("I studied all night; I still failed the exam"), a coordinating conjunction ("I studied all night, but I still failed"), or split it into two sentences.
2. Apostrophe Confusion
Its vs it's. Their vs they're. Your vs you're. These are the most common apostrophe errors in student writing. Remember: apostrophes in contractions replace missing letters ("it is" → "it's"). They don't show possession for pronouns — "its" (no apostrophe) is already possessive.
3. Run-On Sentences
Academic writing that strings too many clauses together becomes exhausting to read. Each sentence should communicate one clear idea. If yours runs past three lines, split it. Clarity beats complexity every time.
4. Passive Voice Overuse
"The experiment was conducted by the researchers" is weaker than "The researchers conducted the experiment." Most style guides, including APA and MLA, recommend limiting passive voice in academic writing. Aim for under 20% passive constructions.
5. Subject-Verb Disagreement
"The team of researchers are working" is wrong — "team" is the subject, not "researchers." "The team is working" is correct. Intervening phrases between subject and verb cause this error constantly in academic writing.
6. Dangling Modifiers
"Having read the study, the results were surprising" — who read the study? The results can't read. The subject of the modifier must be the subject of the main clause: "Having read the study, I found the results surprising."
7. Incorrect Use of "However"
"I studied hard, however, I struggled with the exam" needs a semicolon before "however," not a comma. "However" is a conjunctive adverb, not a coordinating conjunction like "but" or "yet."
8. Inconsistent Tense
Academic papers often shift between present and past tense without reason. Literature reviews use present tense ("Smith argues that..."). Methodology sections use past tense ("We collected data..."). Keep each section consistent.
9. Vague Pronoun References
"The council rejected the proposal because they believed it would fail" — what does "it" refer to? The proposal? Some other plan? Make every pronoun reference unmistakably clear, especially in technical and scientific writing.
10. Redundant Phrases
"Free gift," "past history," "advance planning," "completely finished" — these redundancies weaken academic writing. Each word should earn its place. A free grammar checker will flag most of these automatically.