The 20 Most Common IELTS Grammar Mistakes

Mistake 1: using the present perfect with a finished-time word. 'I have visited that museum last year' mixes an open-time tense with a closed-time marker; the fix is either dropping 'last year' or switching to the past simple. Mistake 2: using the present simple for a situation that started in the past and continues now, a direct translation from languages that don't require the perfect aspect: 'I live here since 2019' needs 'I have lived here since 2019'.

Mistake 3: forgetting to backshift tenses in reported speech after a past reporting verb: 'She said she is tired' should become 'She said she was tired'. Mistake 4: using 'will' for a prior plan rather than a decision made at the moment of speaking: 'I will visit my grandmother tomorrow, I decided last week' should use the present continuous or 'going to' for the pre-planned trip.

• I have visited that museum last year.(mistake 1, finished-time word blocks the present perfect)
• I visited that museum last year.
• I live here since 2019.(mistake 2, 'since' needs the present perfect)
• I have lived here since 2019.

Mistake 5: adding 'the' before a general plural or uncountable noun: 'The pollution is a serious problem worldwide' should drop 'the' when talking about pollution in general, not one specific instance. Mistake 6: treating an uncountable noun as countable: 'many informations' and 'an advice' are both impossible; the fixes are 'a lot of information' and 'a piece of advice' or simply 'some advice'.

Mistake 7: omitting the article before a singular countable noun used generically in a definition: 'Smartphone is a useful invention' needs 'A smartphone is a useful invention' or the plural 'Smartphones are'. Mistake 8: mismatching a determiner and its noun's number, such as 'many equipment' or 'a lot of researches'; equipment and research stay uncountable and singular in form however much of them there is.

• The pollution is a serious problem worldwide.(mistake 5, general reference takes zero article)
• Pollution is a serious problem worldwide.
• I need an advice about my visa application.(mistake 6, advice is uncountable)
• I need some advice about my visa application.

Mistake 9: pairing a verb or adjective with the wrong fixed preposition: 'depend of', 'married with', and 'good in' are all L1-transfer slips; the correct forms are 'depend on', 'married to', and 'good at'. Mistake 10: confusing 'advice' (the uncountable noun) with 'advise' (the verb): 'Can you advice me?' needs the verb spelling 'advise'.

Mistake 11: using 'discuss about' instead of the transitive verb 'discuss', which never takes 'about': 'We discussed about the results' should simply drop 'about'. These small word-form slips rarely block understanding, but examiners count them as basic accuracy errors that a Band 7 script should no longer contain.

• The final decision depends of the budget.(mistake 9, fixed preposition is 'depend on')
• The final decision depends on the budget.
• We discussed about the survey results for an hour.(mistake 11, 'discuss' is transitive, no preposition)
• We discussed the survey results for an hour.

Mistake 12: the comma splice, joining two independent clauses with only a comma, as in 'The exam was difficult, many students failed'. Mistake 13: the sentence fragment, punctuating a subordinate clause as if it were complete, such as 'Because the flight was delayed.' standing alone with no main clause attached.

Mistake 14: starting a sentence with 'But' or 'And' too often in formal writing, which is grammatically fine in moderation but reads as under-developed when it replaces every conjunction a Task 2 essay needs. Mistake 15: overusing 'which' to string clauses together indefinitely: a report which was late, which annoyed the manager, which delayed the launch should be broken into separate, cleaner sentences.

• The exam was difficult, many students failed.(mistake 12, comma splice)
• The exam was difficult, so many students failed.
• Because the flight was delayed.(mistake 13, subordinate clause with no main clause)
• Because the flight was delayed, we missed the connection.

Mistake 16: matching the verb to the nearest noun instead of the true subject: 'The number of applicants have risen' should be 'has risen', because 'the number' (singular) is the subject, not 'applicants'. Mistake 17: a pronoun that doesn't agree with its antecedent in number: 'Every employee must submit their timesheet' is now widely accepted informally, but 'his or her' or a rewritten plural subject is the safer exam choice in formal writing.

Mistake 18: confusing 'fewer' (countable nouns) with 'less' (uncountable nouns): 'less people attended' should be 'fewer people attended', since people can be counted one by one.

• The number of applicants have risen sharply this year.(mistake 16, 'the number' is the true singular subject)
• The number of applicants has risen sharply this year.
• Fewer people attended the conference than expected.(mistake 18, countable nouns take 'fewer')

Mistake 19: keeping question word order inside an indirect question: 'I don't know what is the capital of Vietnam' should follow statement order: 'what the capital of Vietnam is'. Mistake 20: placing an adverb of frequency in the wrong position: 'I go always to the same coffee shop' needs the adverb before the main verb: 'I always go to the same coffee shop'.

• I don't know what is the capital of Vietnam.(mistake 19, indirect questions use statement word order)
• I don't know what the capital of Vietnam is.
• I go always to the same coffee shop after work.(mistake 20, frequency adverb belongs before the main verb)
• I always go to the same coffee shop after work.