Why grammar matters in your test
In a speaking or writing test, the examiner does not only look at your ideas. They also look at how correct and how varied your grammar is. Small, repeated mistakes make you sound less clear, and they pull your score down even when your idea is good.
You do not need perfect grammar to get a high score. You need grammar that is mostly correct and shows some range — different tenses, some longer sentences, and the right small words like a, the, in, and on. The mistakes below are the ones that hurt most because learners make them again and again. Fix a few of these and your writing and speaking both get cleaner. If you focus on writing, our common IELTS Writing mistakes guide covers essay-level errors as well.
The most common grammar mistakes (and the fix)
Each row shows the mistake, a wrong example, the right version, and a quick tip. The English examples stay in English on purpose — read them out loud so the correct form starts to sound normal to you.
| Mistake | Wrong | Right | Quick tip |
|---|---|---|---|
| Subject-verb agreement | He go to work every day. | He goes to work every day. | Add -s to the verb with he, she, or it. |
| Missing article (a/an) | I am student. | I am a student. | Use a or an before a single countable noun. |
| Extra article (the) | I like the music. | I like music. | Drop the when you mean something in general. |
| a vs an | I ate a apple. | I ate an apple. | Use an before a vowel sound (a, e, i, o, u). |
| Verb tense consistency | Yesterday I go to the park and play. | Yesterday I went to the park and played. | Keep the whole story in one time (all past here). |
| Preposition of time (in/on/at) | I will meet you in Monday. | I will meet you on Monday. | on for days, in for months/years, at for a clock time. |
| Fixed verb + preposition | I am good in English. It depends of you. | I am good at English. It depends on you. | Learn the verb and its preposition as one unit. |
| Uncountable noun made plural | I need some informations. | I need some information. | Some nouns have no plural: information, news, progress. |
| Counting advice/furniture | He gave me many advices. | He gave me a lot of advice. | Say a piece of advice, not an advice. |
| Word order | I like very much this book. | I like this book very much. | Keep subject-verb-object; put very much at the end. |
| Run-on sentence | I was tired I went to bed. | I was tired, so I went to bed. | Join two ideas with a linking word or a full stop. |
| since vs for | I have lived here since three years. | I have lived here for three years. | for + a length of time; since + a start point. |
| Third conditional | If I would have known, I will help. | If I had known, I would have helped. | Past that did not happen: if + had done, would have done. |
| much vs many | How much people came? | How many people came? | many for things you can count; much for things you can't. |
| fewer vs less | There were less people today. | There were fewer people today. | fewer for countable nouns; less for uncountable. |
| make vs do | I must make my homework. | I must do my homework. | do a task or job; make a thing you create. |
Sixteen rows may look like a lot, but they fall into just a few groups: the small words (a/an/the, in/on/at), keeping your tenses steady, and a set of confusing pairs. The next section explains the trickiest ones in plain terms.
The confusing pairs, explained simply
A few of these mistakes come up so often that they deserve a closer look. Once you understand the rule, you can catch yourself before you make the error.
Countable or not? A countable noun is something you can count: one book, two books. An uncountable noun is something you take as a whole: water, information, advice, furniture. Countable nouns can be plural and take many and fewer. Uncountable nouns stay singular and take much and less. So it is many chairs but much furniture, fewer mistakes but less time.
since vs for. Use for with a length of time: for two hours, for five years, for a long time. Use since with the point when something started: since Monday, since 2019, since I was a child. A quick test: if you can say "a period of ___", use for; if it is a moment in time, use since.
make vs do. In general, you do an action, a task, or a job (do your homework, do the dishes, do business), and you make something new or a result (make a cake, make a plan, make a mistake). These are set phrases, so the best way to learn them is to meet them in real sentences — our guide to building English vocabulary shows how to collect and remember word pairs like these.
The third conditional. This is for a past situation that did not happen and its imagined result. The shape is fixed: if + had + past participle, then would have + past participle. So: If I had studied more, I would have passed. A common error is putting would in the if part — never do that.
How to fix grammar for good
Knowing a rule is not the same as using it without thinking. To make correct grammar automatic, practise in small, focused steps.
- Pick two mistakes at a time. Watch only for those when you write or speak this week. Add two more next week.
- Read your writing out loud. Many errors — a missing the, a run-on sentence, a wrong tense — are easy to hear even when they are hard to see.
- Keep a personal error list. Every time someone corrects you, write the wrong and the right version side by side. Review it before your next practice.
- Learn phrases, not single rules. Store good at, depend on, and a piece of advice as whole chunks so the small words come out right.
- Practise both skills. The same grammar helps your speaking and your writing. For longer written answers, our IELTS Writing guide shows how correct grammar fits into a full essay.
Most learners cannot spot every mistake in their own work — the errors you repeat are the ones you stop noticing. That is where feedback helps. Aflo reads or listens to a real answer and points to the exact grammar that slipped, so you know which mistake to work on next instead of guessing.
Frequently asked questions
What is the most common grammar mistake English learners make?
Two stand out: leaving out small words like a, an, and the, and forgetting subject-verb agreement (saying "he go" instead of "he goes"). Both are easy to fix once you watch for them, and both come up in speaking and writing.
Why is "informations" wrong?
Because information is an uncountable noun — you take it as a whole, not as separate items. Uncountable nouns have no plural and no a/an. Say "some information" or "a piece of information." The same is true for advice, news, furniture, and progress.
When do I use "since" and when do I use "for"?
Use for with a length of time: for three years, for two hours. Use since with the point when something began: since 2019, since Monday. If you can put the words after "a period of," use for; if it is a moment in time, use since.
What is the difference between "much" and "many"?
Use many with things you can count (many people, many books) and much with things you can't count (much water, much time). The same rule splits fewer (countable) from less (uncountable): fewer mistakes, less time.
Do small grammar mistakes really lower my test score?
Yes, when they repeat. One slip is fine, but the same error again and again makes you harder to follow and shows a narrow range of grammar, which pulls down your score. Fixing a few common mistakes is one of the fastest ways to sound more correct.