Today, we will look at ten of the most common grammatical errors in English. I’ll show you what they are, why they are problematic, how to identify them, and how to fix them. By the time you’re finished here, you should have a much better understanding of English grammar!

Subject-Verb Disagreement

This is an incredibly common error, particularly among IELTS writing candidates. Basically, it involves having the subject and verb of a clause in forms that do not match. For example:

  • My brothers is coming to visit me this weekend.

Here, we have a plural subject (brothers) and a singular verb (is). Instead, we need to keep them in the same form:

  • My brothers are coming to visit me this weekend.
  • My brother is coming to visit me this weekend.

Depending on whether you have one or more brothers, you should change to either of the above options.

You can learn more about subject-verb agreement here.

Pronoun-Antecedent Disagreement

The word “antecedent” might seem unfamiliar, but don’t worry. It means something from earlier that is being referred to. In this particular situation, it means that the noun that a pronoun replaces is not in the same form as the pronoun. For example:

  • My uncle is a railway engineer. She earns a great salary.

I think most people can easily see the error here. We have replaced “uncle” with “she.” However, an uncle is a male person and “she” refers to females, so this is wrong. We need to fix this:

  • My uncle is a railway engineer. He earns a great salary.
  • My aunt is a railway engineer. She earns a great salary.

Depending on what was meant, either of these could be correct.

It is not always gender that is the problem. It could be number:

  • I bought a new computer. They were really expensive!

In this case, we have replaced a singular noun (computer) with a plural pronoun (they), which is totally incorrect. We need to fix this:

  • I bought a new computer. It was really expensive!
  • I bought some new computers. They were really expensive!

Remember to pay attention to pluralisation. Mistakes of this kind can be really serious, confusing your reader and possibly getting you a very low IELTS score.

Run-on Sentences

A run-on sentence is one lacking in punctuation. This features two or more independent clauses that should either be linked by punctuation or words, or divided into two distinct sentences. For example:

  • My teacher and I had a long conversation we spoke about many different things.

Here, we have two independent clauses:

  1. My teacher and I had a long conversation
  2. We spoke about many different things

These need to be punctuated properly because right now there is nothing joining those two clauses. There are different ways to fix these and it totally depends on the individual problem. Here, the best way is probably to make two sentences:

  • My teacher and I had a long conversation. We spoke about many different things.

Sentence Fragments

A sentence fragment is a group of words that purports to be a sentence but is missing something grammatically and thus is considered incomplete. All sentences in English should have:

  1. Subject
  2. Verb
  3. Complete thought

If any of these is missing, we have a sentence fragment. For example:

  • Because it is cold outside.

This has a subject and verb but no complete thought. That’s because the word “because” introduces an idea that is not finished. It needs to be attached to another clause (a dependent one) in order to make sense. We could fix it in a number of ways:

  • She wants to stay home and watch movies because it is cold outside.
  • Because it is cold outside, we stayed home and had a cup of tea.

Typically, sentences that are missing a complete thought are the hardest to recognise. A missing subject or verb is easier.

Comma Splices

A comma splice is when two independent clauses are joined by just a comma. This is a mistake that people make when attempting to form compound sentences. For example:

  • The price of oil rose by 5%, the markets panicked.

There are various ways to fix this. For example:

  • The price of oil rose by 5%, which caused the markets to panic.
  • The price of oil rose by 5%, so the markets panicked.
  • Because the price of oil rose by 5%, the markets panicked.
  • The price of oil rose by 5%, and then the markets panicked.
  • The price of oil rose by 5%; therefore, the markets panicked.

As you can see, there are various possibilities. Basically, you should figure out the different types of sentence, and then link these clauses both grammatically and logically.

You can learn more about comma splices here.

Misplaced Modifiers

A modifier is a word or phrase, such as an adjective or adverb, that modifies another word in that sentence. These are optional but add detail to our language. Sometimes, modifiers can be moved about in a sentence, but whether or not they can technically be moved, we should always try to put them where they make the most sense. Sometimes, a modifier is accidentally put somewhere that suggests a different meaning.

Look at these two sentences:

  1. We carefully checked the documents she had submitted.
  2. We checked the documents she had submitted carefully.

These could both be correct but they actually present quite different meanings. The first one shows that the people were careful about checking the documents. The second could be read in two ways. Either it has the same meaning as the first or the woman was careful about how she submitted the documents.

Dangling Participles

Participle clauses are great for condensing information into shorter chunks, but they present a problem. The subject of both clauses must be the same. This means we can easily make a mistake. For example:

  • Waiting for the bus home, Sarah’s phone rang.

What is the subject of the first clause? It should be Sarah, but that’s not logical here. Thus, it is a dangling participle.

We can fix this in various ways. We can try to make a basic participle clause sentence:  

  • Waiting for the bus home, Sarah heard her phone ring.

Now, the subject of both sentences is Sarah. Easy!

We could also change the grammar a little for other options:

  • While she was waiting for the bus home, Sarah’s phone rang.

By making the subject of the first clause clear, we no longer have to worry about the subject of the second clause being the same. Note that this is no longer a participle clause, though.

(Note: This is sometimes called a “dangling modifier.” I use the term “dangling participle” because I often teach participle clauses and it’s easier to use the same terminology. You can read about participle clauses here.)

Lack of Parallelism

Parallelism is one of those things that sounds really complicated but is actually quite easy. It’s also a great way to make your writing more logical, so that your ideas are expressed clearly. However, when we make an error, we can end up with faulty parallelism:

  • He likes football, rugby, and watches cricket.

The problem here is that we have a list but not all of the items are in the same form:


We should endeavour to put the items of a list into the same form:

  • He likes football, rugby, and cricket.
  • He likes playing football and rugby and watching cricket.

Either of these is acceptable, but they present different meanings. The first shows that he just likes these three sports. The second highlights the fact that he plays two but watches one.

Note that it can be a bit trickier with verbs as we not only keep verbs together but should put them into the same form unless we have a good reason not to:

  • Do prefer watching movies at home or go to the cinema?

We need to fix one of these verbs:

  • Do prefer watching movies at home or going to the cinema?

The easiest and clearest way is to put both verbs into the “-ing” form.

Incorrect Verb Tenses

Speaking of verbs, we now come to perhaps the most difficult part of grammar and, from an IELTS perspective, possibly the biggest mistake that people make: using an incorrect verb tense.

In English, we have twelve verb tenses, which are made from the four aspects (simple, perfect, continuous, perfect-continuous) being put into three times (past, present, future):

These have a lot of rules about their use and even their construction can be confusing for some people. I have often remarked that the present perfect tense is criminally underused by English learners whilst the continuous forms are shockingly overused.

Here’s a mistake that I often see:

  • In 1998, the price of beets is $15/kg.

This is wrong because the verb tense does not match the time given. This is from the past, so we need to use the past simple:

  • In 1998, the price of beets was $15/kg.

This is a vast topic to cover and it is worth practising often, and then finding the verb tenses that you struggle with the most. Once you know those, work to eliminate those errors.

Learn about the most common verb tenses here.

Homophone Confusion

Homophones are words that sound similar, such as “by” and “buy” and “bye.” We have many of these in English, which means that we have a lot of jokes in anglophone cultures, but at the same time it makes writing quite hard. Here’s an example of a common error:

  • I could of past my exam if I’d tried harder.

Actually, there are two mistakes here!

  • could of –> could have
  • past –> passed

Thus, this sentence should be:

  • I could have passed my exam if I’d tried harder.

This is one error that’s even more common among native speakers than English learners! That shows you just how difficult this language can be.

Final Thoughts

There are lots of different grammatical mistakes that people make, particularly in the IELTS test. I had to omit lots of types of errors in order to make this list. One problem is that different people have totally different problems. People in China usually struggle with finding the right pronoun or transition, whereas people from Russian find articles the hardest. People from India tend to struggle with verb tense and most French find that adverb placement is the hardest thing. You should figure out your own mistakes and work to eliminate them.