Error Detective

Spot English grammar mistakes, fix sentences and learn to recognise natural English. Test your proofreading skills with interactive error correction exercises from A2 to C2.

Grammar & vocabularySpot · Fix · InvestigateA2–C2Free · No account

INTERACTIVE ENGLISH ERROR CORRECTION

Choose your level and investigation mode. Some cases contain an error; some are correct; others can sound more natural.

LEARN BY FINDING THE CLUES

Free English grammar error correction exercises

Can you spot a grammar mistake, correct an awkward expression or recognise an English sentence that is already right? Error Detective turns proofreading into a practical English grammar game. Practise common English mistakes, sentence correction and more natural word choices at your own pace.

01 · Spot the errorIdentify a word or phrase that needs attention. Some sentences have no mistake.

02 · Fix the sentenceWrite a corrected sentence, then see an explanation of the language pattern.

03 · InvestigateDecide whether a sentence contains a grammar error, an unnatural expression or no problem.

Improve accuracy from A2 to C2

Build confidence with articles, verb tenses, prepositions and word order at lower levels. At B2, C1 and C2, explore dependent prepositions, collocations, advanced structures and natural phrasing. The aim is not simply to find wrong answers: it's to notice why one expression works better than another.

What is the difference between incorrect and unnatural English?

Grammar error: “She explained me the problem” needs to become “She explained the problem to me.” More natural English: “I strongly enjoyed the film” may be understood, but “I really enjoyed the film” is a more typical combination. A grammatically correct sentence may also need no changes.

More free English practice

Sentence Builder →Practise English word order, questions and sentence structure.Collocation Challenge →Choose natural English word combinations and expressions.Word Formation →Train vocabulary and Cambridge-style word formation.

Explore all free English practice activities, check vocabulary with our CEFR Vocabulary Checker or discover our Cambridge English preparation courses.

Developed by C2 English School for independent learners. This is an original practice activity, not an official Cambridge examination paper.