HomeCasa Grammar drills built from your own mistakes in a foreign language
Paste sentences you got wrong and get a diagnosis of your error patterns, each rule explained simply, and graded grammar drills with an answer key or interactive correction. Designed for ChatGPT, Claude, Gemini and Microsoft Copilot. It includes 4 customizable variables and you can copy it for free in one click.
Intermediate · Text · Pending editorial review
Prompt
Act as a {{language}} teacher who specializes in fixing the recurring grammar mistakes of English-speaking learners.
Context:
- Language I am learning: {{language}}
- My level: {{level}}
- Sentences with mistakes (mine or corrected by my teacher): {{mistakes}}
- Practice mode: {{mode}}
Deliverables:
1. Diagnosis: correct each sentence and group the mistakes by pattern (for example, verb tenses, prepositions, word order, agreement). Say which ones repeat most.
2. For each pattern: the rule in 2-3 simple sentences, why English speakers typically get it wrong and one correct versus incorrect example.
3. Drills for each pattern, 6 per pattern and increasing in difficulty: correct the sentence, fill in the blank and transform the sentence (for example, statement to question or present to past).
4. A one-line-per-rule summary sheet for review.
5. The answer key at the end, separate from the drills.
Interactive mode: if the mode is "interactive", do not show the answer key. Present one pattern's drills at a time, wait for my answers, correct them explaining every mistake and then move on.
Constraints:
- Do not mark correct regional variants or registers as mistakes; if a sentence is acceptable in some context, explain it.
- If a sentence is ambiguous and you cannot tell what I meant, ask me before correcting it.
- Do not invent rules: if a usage is disputed among grammar references, say so.How to use it
Collect real sentences you got wrong: corrected essays, messages or homework. The more sentences, the clearer the pattern. Do the drills without looking at the rules and repeat them a week later.
Usage example
Language: Spanish · Level: B1 · Mistakes: "Yo soy cansado", "Me gusta los perros", "Fui a la playa cuando era niño todos los veranos" · Mode: interactive.
Sample output
Diagnosis
| Your sentence | Correction | Pattern |
|---|---|---|
| Yo soy cansado. | Estoy cansado. | ser vs. estar |
| Me gusta los perros. | Me gustan los perros. | gustar agrees with the thing liked |
| Fui a la playa cada verano cuando fui niño. | Iba a la playa cada verano cuando era niño. | Preterite vs. imperfect |
| Estoy viviendo en Madrid desde 2019. | Vivo en Madrid desde 2019. | Present with desde |
Most frequent pattern: verb choice and tense (three of the four sentences). Note: Estoy viviendo en Madrid desde 2019 is understandable and heard in speech, but vivo (or llevo viviendo) is the more natural choice.
Pattern 1: preterite vs. imperfect
Rule: use the imperfect for habits and background in the past (cada verano, cuando era niño); use the preterite for completed, one-off events. Why English speakers slip: English uses "went" for both.
Drills (interactive mode)
- Correct: Cuando fui pequeña, jugué en el parque todos los días.
- Fill in: De niños, mis hermanos y yo ___ (ver) dibujos cada mañana.
- Transform to a question: Siempre comían en casa de la abuela.
Send your answers and we'll go through them before the next pattern. …
Key facts
- Category
- Education & study · Language learning
- Output type
- Text
- Level
- Intermediate
- Designed for
- ChatGPT, Claude, Gemini and Microsoft Copilot
- Verified in
- Pending editorial verification
- Variables
- Language you are learning, Your level, Sentences with mistakes and Practice mode
- Language
- English
- Price
- Free, no sign-up
- Updated
- Nov 7, 2026
Frequently asked questions
Why start from my mistakes instead of a grammar book?
The mistakes you repeat are the ones that hurt you most, and a generic book may not cover them. Drilling exactly those patterns brings faster results.
How many sentences should I paste?
Eight to ten sentences already reveal patterns. If you paste a whole essay corrected by your teacher, the AI may spot mistakes you had not noticed.
What is this prompt for?
Paste sentences you got wrong and get a diagnosis of your error patterns, each rule explained simply, and graded grammar drills with an answer key or interactive correction.
Which AI tools does it work with?
It is designed for ChatGPT, Claude, Gemini and Microsoft Copilot. We have not verified it in these tools yet, so results may vary between them.
How do I customize the prompt?
Click “Customize” and fill in the variables (Language you are learning, Your level, Sentences with mistakes and Practice mode). The text updates instantly and you can then copy it in one click. Values are stored only in your browser.
Do I need experience to use it?
It is intermediate: it helps to know the topic so you can provide good context and review the result critically.
Is this prompt free?
Yes. Every HomeCasa Prompts prompt is free, with no sign-up or subscription. You can also use them in professional projects.
Can I trust the AI output?
Treat it as a high-quality draft: always check data, figures and important claims before publishing or making decisions.