Common English Grammar Mistakes Adults Make (And How to Fix Them)

You’ve been speaking English for years. Maybe decades. And yet, certain mistakes keep appearing in your emails, your IELTS writing, your meetings. The same ones, over and over. That’s not unusual — it’s actually one of the most consistent things I see with adult learners at every level. The errors aren’t random. They’re patterned, predictable, and very fixable.

This post covers four of the most common English grammar mistakes adults make, explains exactly why they happen, and gives you a short exercise to test yourself at the end.

The Four Mistakes (And Why Adults Keep Making Them)

1. Confusing “make” and “do”

This one trips up speakers from almost every language background. The rule sounds simple until you actually try to apply it.

The pattern: Use make for creating or producing something. Use do for actions, tasks, and activities — especially ones without a physical end product.

• Correct: I need to make a decision before the meeting.
• Correct: Can you do me a favour?
• Wrong: I need to do a decision. ✗

In Business English, the collocations matter enormously. You make a proposal, make progress, and make an appointment. You do research, do business, and do your best. These aren’t logical — they’re fixed phrases, and the only way to get them right consistently is exposure and practice.

2. Misusing the Present Perfect

This is probably the single most common grammar mistake I see in adult learners’ writing, especially from speakers of Romance languages or Asian languages where this tense either doesn’t exist or works differently.

The rule: Use the present perfect (have/has + past participle) when the action is connected to the present — when the exact time isn’t specified, or the result still matters now.

• Correct: I have sent the report. (It’s done. You have it now.)
• Wrong: I have sent the report yesterday. ✗

Once you name a finished time (yesterday, last week, in 2019), you must use simple past. “Yesterday” closes the connection to the present. The tense has to change with it.

• Correct: I sent the report yesterday.

In IELTS Writing Task 1 and Task 2, misusing the present perfect is a reliable way to lose marks on Grammatical Range and Accuracy. Examiners notice.

3. Articles: “a”, “an”, and “the” (or nothing at all)

If your first language has no articles — Arabic speakers, Russian speakers, Japanese speakers, I see you — this one is genuinely hard. There’s no shortcut, but there is a core principle worth locking in.

Use “the” when both speaker and listener know which specific thing you mean. Use “a/an” when you’re introducing something for the first time or talking about one of many.

• Correct: We need to find a solution. (Any solution. We haven’t decided yet.)
• Correct: The solution we discussed on Tuesday works best. (That specific one.)

In professional emails, article errors make writing feel unpolished even when the vocabulary is strong. This is one of those areas where daily reading and coached feedback makes a real difference. It’s the kind of persistent error that daily coaching sessions are built to catch and correct. If you want that level of attention on your writing, find out how the daily coaching programme works here.

4. Subject-Verb Agreement with Collective Nouns

This one catches even confident speakers off guard.

In American English, collective nouns (team, company, government, staff) take a singular verb.
In British English, they can take either singular or plural, depending on whether you’re emphasising the group or the individuals in it.

• American English: The team is ready to present.
• British English: The team are ready to present. (Also acceptable.)
• Wrong in any variety: The team are ready, but it have already submitted the report. ✗ (mixing is the problem)

Pick one and be consistent. In IELTS, either is accepted as long as you don’t mix conventions mid-paragraph.

Practice Exercise

Rewrite or complete each sentence correctly. There may be more than one error in some sentences.

1. “I have finished the presentation last night and send it to the client.”
2. “We need to do a good impression during the pitch.”
3. “The management have announced a new policy yesterday.”
4. “She is working in a finance sector for over ten years.”
5. “Our team are performing well, and it has already exceeded the target.”

Work through these carefully. Think about which rule applies to each one before you rewrite. These are exactly the kinds of structured grammar drills we work through in daily coaching sessions — if you’d like that kind of regular, focused practice, here’s how the coaching programme works.

Vocabulary to Know

• collocation /ˌkɒl.əˈkeɪ.ʃən/ – Level: B2 – a pair or group of words that are habitually used together and sound natural to native speakers. Example: “Make a decision” is a collocation; “do a decision” is not.
• present perfect /ˈprez.ənt ˈpɜː.fɪkt/ – Level: B1 – a verb tense formed with “have/has” plus a past participle, used to connect a past action to the present. Example: She has worked in London for three years.
• past participle /pɑːst pɑːˈtɪs.ɪ.pəl/ – Level: B1 – the form of a verb used in perfect tenses and passive constructions (e.g. written, sent, finished). Example: The report has been written and approved.
• collective noun /kəˈlek.tɪv naʊn/ – Level: B2 – a noun that refers to a group of people or things as a single unit, such as “team”, “staff”, or “committee”. Example: The committee meets every Thursday to review proposals.
• subject-verb agreement /ˈsʌb.dʒɪkt vɜːb əˈɡriː.mənt/ – Level: B2 – the grammatical rule that a verb must match its subject in number (singular or plural). Example: The manager reviews all contracts before signing.
• definite article /ˈdef.ɪ.nət ˈɑː.tɪ.kəl/ – Level: B1 – the word “the”, used to refer to a specific, identified noun. Example: Please review the document I sent this morning.
• grammatical range and accuracy /ɡrəˈmæt.ɪ.kəl reɪndʒ ənd ˈæk.jʊ.rə.si/ – Level: C1 – one of the four IELTS marking criteria, assessing how varied and correct a candidate’s grammar is. Example: Using only simple sentences will limit your grammatical range and accuracy score.
• to trip someone up /tə trɪp ˈsʌm.wʌn ʌp/ – Level: B2 – an idiom meaning to cause someone to make a mistake or become confused. Example: Irregular verbs often trip up even advanced learners.
• fixed phrase /fɪkst freɪz/ – Level: B2 – an expression whose words are set and cannot be changed without making it sound unnatural. Example: “Make progress” is a fixed phrase — you cannot say “do progress”.
• unpolished /ʌnˈpɒl.ɪʃt/ – Level: C1 – lacking refinement or professionalism; used to describe writing or speech that feels rough or not fully developed. Example: Article errors can make an otherwise strong email sound unpolished.

Frequently Asked Questions

How long does it take to stop making these grammar mistakes?

Honestly, it depends on how much targeted feedback you’re getting. Adults can correct deeply ingrained habits, but passive exposure alone rarely does it. You need someone pointing out the specific error at the moment you make it. Most learners see noticeable improvement within a few weeks of consistent, focused practice.

Are these mistakes serious enough to affect my IELTS score?

Yes, particularly present perfect misuse and article errors. The IELTS examiner is specifically assessing your grammatical accuracy, and these errors appear in the marking criteria under both Task Achievement and Grammatical Range and Accuracy. Repeated errors in either area will push your band score down, even if your ideas are strong.

Do native speakers make these mistakes too?

Some of them, yes. Subject-verb agreement with collective nouns, for example, varies by region and register. But native speakers usually get articles and the present perfect right intuitively, because they’ve heard correct usage thousands of times. That’s exactly what you’re building toward — not memorising rules, but developing the same intuition through repeated, correct exposure.

Ready to Fix These for Good?

Reading about grammar rules is a start. Actually correcting them under feedback is what makes them stick. If you want regular, personalised sessions where someone is actively looking at your specific errors and helping you work through them, that’s what the daily coaching programme at richardg.xyz is for. No fluff, no generic exercises — just focused work on what you actually get wrong. Find out more here.