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And you instantly knew what was wrong.
TeacherCheck brings that feeling to the way you write English online.
Write exactly how you normally would. Use your words, your slang, your natural cadence.
TeacherCheck finds genuine English mistakes without policing your casual voice or tone.
See the correction directly above your words and understand why with a concise teacher explanation.
Most AI writing tools want to rewrite what you said into stiff, sterile corporate prose.
TeacherCheck takes a different approach.
Your words stay yours. Your personality stays yours. We only fix the English that actually needs fixing. Read our guide on why fixing grammar beats AI rewriting →
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TeacherCheck is an interactive English grammar checking application styled after a school teacher's notebook corrections. Users can enter English sentences or paragraphs to identify objective grammar errors (such as subject-verb agreement, irregular verb forms, and tense mismatches) with visual red-pen strike-throughs and word-above corrections, while preserving authentic informal expressions and personal tone.
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Your professors want to read your perspective, not a synthetic chatbot's prose. Most automated writing tools completely rewrite your sentences with corporate jargon, often triggering AI detection algorithms. TeacherCheck marks only genuine grammatical mistakes directly above your words, leaving your ideas, structure, and natural voice completely untouched.
When writing essays, research summaries, and assignments, students frequently turn to AI rewriters to polish their drafts. However, heavy-handed rewriters introduce two significant problems for academic writing:
In student submissions, the vast majority of points lost to mechanics stem from four recurring sentence-level errors. Here is how a teacher approaches each one:
A comma splice happens when two independent clauses (complete thoughts that could stand alone as separate sentences) are joined with only a comma.
| Draft Sentence | Teacher's Correction | Why It Matters |
|---|---|---|
| The experiment failed, we did not calibrate the sensors in time. | The experiment failed because we did not calibrate the sensors in time. (Or: The experiment failed; we did not calibrate...) | A comma alone cannot join two independent clauses without a coordinating conjunction. |
When prepositional phrases or parenthetical clauses sit between the subject and verb, writers often mistakenly match the verb to the nearest noun.
| Draft Sentence | Teacher's Correction | Why It Matters |
|---|---|---|
| The list of required laboratory readings are available on the portal. | The list of required laboratory readings is available on the portal. | The singular subject is list, not the plural noun readings inside the prepositional phrase. |
Pronouns like this, that, it, or they must point clearly to a single preceding noun. When two possible referents exist, readers must guess your meaning.
| Draft Sentence | Teacher's Correction | Why It Matters |
|---|---|---|
| The professor handed the student the syllabus, and then he left the room. | After handing the syllabus to the student, the professor left the room. | Clarifies who he refers to, eliminating confusion between the professor and the student. |
Academic essays are frequently marked down for quick typographical errors involving words that sound identical. Check our in-depth guides for the two most common student traps:
TeacherCheck was built specifically around the philosophy of a real teacher sitting beside you with a red pen. When you paste an essay sentence:
Grammatical Range and Accuracy accounts for 25% of your IELTS Writing score. To achieve Band 7 or higher, the official public descriptors require that you produce "frequent error-free sentences" and show good control of grammar and punctuation. AI paraphrasers often introduce unnatural, unidiomatic phrasing that lowers your Lexical Resource score. TeacherCheck pinpoints exact grammatical errors while keeping your arguments natural.
The difference between Band 6 and Band 7 in IELTS Writing (both Academic and General Training) is rarely about having "fancier" vocabulary. Rather, it comes down to error density and sentence control:
The key hurdle for most test-takers stuck at Band 6.0 or 6.5 is not vocabulary—it is the presence of recurring, systematic slips in articles, prepositions, and clause combinations.
Candidates often over-apply the definite article (the) before general uncountable concepts, or omit it before specific post-modified nouns.
| Candidate Draft | Examiner Correction | Grammar Rule |
|---|---|---|
| The society should invest more in education. | Society should invest more in education. | When speaking of human society in general, do not use the. Only use the when specifying a particular society (e.g., the society of ancient Rome). |
| Due to rapid development of technology... | Due to the rapid development of technology... | When a noun is followed by an of phrase, the definite article is required. |
When listing causes, effects, or solutions, all items in the series must share the same grammatical form (e.g., all gerunds, all infinitives, or all noun phrases).
| Candidate Draft | Examiner Correction | Grammar Rule |
|---|---|---|
| Governments should focus on building hospitals, improving transit, and to reduce pollution. | Governments should focus on building hospitals, improving transit, and reducing pollution. | All three items coordinated by and must use parallel gerund forms (-ing). |
Complex structures like second and third conditionals demonstrate grammatical range, but tense mismatches frequently spoil the execution.
| Candidate Draft | Examiner Correction | Grammar Rule |
|---|---|---|
| If governments had implemented these policies earlier, the situation will be different today. | If governments had implemented these policies earlier, the situation would be different today. | In mixed conditionals combining past condition with present result, use would + bare infinitive, not will. |
Examiners notice when stress leads to careless spelling errors. Review our rules for it's vs its and affect vs effect to protect your punctuation and lexical scores.
During test prep, do not paste entire essays into generic AI tools that rewrite them wholesale. Instead, adopt a deliberate practice routine:
There is a fundamental difference between correcting language and erasing someone's voice. Most AI writing tools act like over-eager editors: you give them a human sentence, and they return a sanitized, corporate paragraph packed with buzzwords. TeacherCheck takes the red-pen approach: we preserve your authentic tone, keep your phrasing intact, and fix only the grammar that actually needs fixing.
Modern Large Language Models are heavily tuned toward polite, generic corporate prose. When you run text through standard paraphrasing tools, they tend to introduce distinct issues:
| Feature / Characteristic | TeacherCheck | Generic AI Paraphrasers |
|---|---|---|
| Core Goal | Surgical correction of actual grammatical, spelling, and punctuation errors. | Regenerative rewriting of complete sentences and paragraphs. |
| Personal Voice | 100% Preserved. Casual, direct, technical, or academic tone remains yours. | Frequently replaced with homogenized corporate prose. |
| Transparency | Red-pen strike-throughs. You see exact word replacements and a brief teacher note. | Black-box output: a whole new sentence where it is hard to tell what was actually wrong. |
| AI Detection Risk | Extremely Low. Because sentence structure and vocabulary are yours, human burstiness is retained. | High risk of triggering AI detectors due to uniform AI perplexity patterns. |
| Educational Value | Explains why an error occurred so you learn and improve. | Encourages copy-pasting without understanding the underlying rule. |
Original Input: "Bro I finally fixed this bug, it was killing me for hours 😂"
Original Input: "I seen the report yesterday, its numbers looks promising."
We believe in choosing the right tool for the job:
Whenever you write it's, expand it in your head to "it is" or "it has". If the sentence still makes sense, keep the apostrophe. If it sounds broken or nonsense, use its without an apostrophe.
| Word | Grammatical Role | Meaning | Example |
|---|---|---|---|
| It's (with apostrophe) | Contraction | Short for "it is" or "it has" | It's a beautiful morning. (It is) It's been raining all day. (It has) |
| Its (no apostrophe) | Possessive Determiner | Belonging to it (shows ownership) | The dog wagged its tail. The company released its report. |
| Never correct | Does not exist in the English language | Never use this form under any circumstance. |
The confusion is natural because in English, we usually add 's to nouns to show possession (e.g., Sarah's book, the cat's toy, the university's policy).
However, personal pronouns never take apostrophes for possession:
Just as you would never write "the book is her's", you should never write "the dog wagged it's tail".
Remember the acronym RAVEN: Remember Affect = Verb, Effect = Noun. In over 95% of everyday, academic, and professional writing, affect is the action you take, and effect is the result you see.
| Word | Part of Speech | Meaning | Quick Test |
|---|---|---|---|
| Affect | Verb (Action) | To influence, to produce a change in, to impact | Can you substitute "influence" or "change"? If yes, use affect. |
| Effect | Noun (Thing) | A result, an outcome, a consequence | Can you put "the", "an", or "side" in front of it? If yes, use effect. |
Use affect when something is acting upon something else:
Use effect when referring to the outcome or result:
While RAVEN holds for almost all everyday situations, English has two rare exceptions worth knowing:
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