5 common grammatical errors and how to avoid making them

Do you ever worry about the grammar in your writing, and feel unsure how to fix it? Maybe you don’t have the time or money to get it professionally edited, or this may be overkill for, say, a personal blog post. Luckily, you can take other steps to reduce the chances of grammatical mistakes in your prose. Here we look at five of the most common errors, to help you identify and fix them. Note: an asterisk (*) before a phrase means it’s considered incorrect.

Subject–verb disagreement

Agreement is a common source of error in writing, as any proofreader or subeditor can tell you. When the grammatical subject is straightforward, mistakes are rare – no one with basic competence in English is likely to write, *The festival are starting, or *My favourites is chocolate.

But grammatical subjects are often more complicated than this, and subject–verb disagreement can then sneak in. Take this line: *Implementation of organisational checks and balances have improved. Because of the salience of the plural nouns checks and balances, and their proximity to the verb, the writer didn’t notice that the grammatical subject is the singular noun implementation. So have should be has. This kind of mistake is very common.

There can also be uncertainty over whether a singular or plural use is correct. What about collective nouns like team, staff, and government, and words like neither, as in Neither of the plans is/are perfect? These can all be singular or plural – just make sure their use is locally consistent and appropriate. Our post on grammatical concord explains this in more detail.

Comma splices

A comma splice is when you use a comma to join two independent clauses, as in It’s a sunny day, we’re off to the beach. Critics insist that such clauses be separated by a stronger mark than a comma, such as a semicolon, dash, or full stop, or by a coordinating conjunction, such as and or so.

The comma splice has long been used for stylistic effect, not just in casual writing but in literature, so its other names comma fault and comma error are a bit unfair.

But if you’re writing official or business English, it’s best avoided. In other contexts it should be used with caution, and only if you know what you’re doing, because many readers will consider it a mistake. You won’t find many comma splices on Macmillan Dictionary Blog.

Dangling modifiers

Dangling modifiers, though frequent in most varieties of English, have never become fully respectable, and perhaps for good reason. They’re often inconspicuous except to editors and pedants, but sometimes they stick out like a sore thumb and invite misreading. ‘It’s the funny ones that cause trouble,’ says the Columbia Guide to Standard American English.

This example from a motorbike magazine illustrates the point: From Llandrindod you proceed along the lovely valley of the Ithon, growing more beautiful as you proceed. The modifier growing more beautiful refers to the valley, but it attaches too readily to the pronoun you, suggesting that the motorcyclist is growing more beautiful as the journey proceeds. This post by Gill Francis has further examples and discussion.

Apostrophe catastrophes

Apostrophe errors are extremely common, especially when the possessive case is involved. Take the phrase the people’s choice, which means ‘the choice of the people’. This is often incorrectly styled as *the peoples’ choice, which means ‘the choice of the peoples’. Writers somehow forget, when they’re placing the apostrophe, that people is already plural. A similar mistake occurs with other plurals formed without an ‘s’, like children – instead of children’s, we get *childrens’. So be careful where you put the mark.

The use of its and it’s is another frequent source of error, and it can diminish authority. It can happen easily, because we think of the apostrophe as marking possessive case: I read Mary’s book, the cat’s bowl needs filling, but *The company found it’s way. To avoid this mistake, remember that it’s is always short for it is or it has. Its has the same pattern as other possessive pronouns like hers and theirs, which take no apostrophe: It’s time for its walk.

Strictly speaking, apostrophes fall under orthography rather than grammar. In general usage, though, grammar often refers to spelling, punctuation, and style, so we’ve included the apostrophe here.

Faulty parallelism

Faulty parallelism is a common lapse in style that sometimes entails grammatical error too. Parallel structure helps readers make sense of the material. When structures that should be parallel are not – through ignorance, haste, inattention, or lack of care – the prose is harder for readers to follow. For example, I could write that parallelism is important because:

  • makes reading more efficient
  • it improves clarity
  • because it enhances logic
  • courtesy to readers.

This list is legible but awkward, because the points are not structured in a parallel way. Instead, I could write that parallelism is important because it:

  • makes reading more efficient
  • improves clarity
  • enhances logic
  • is a courtesy to readers.

Here, each point follows naturally from the grammatical subject it, opening with a verb in the third-person singular. This makes the list a lot easier to follow.

Faulty parallelism also arises with constructions like as much (as) or more than. Writers often omit the second as, creating phrases like as good or better than we expected. This won’t be misinterpreted, and it’s OK in casual contexts. But you wouldn’t say as good than, so if you want to be strictly grammatical, include the second as, and consider adding commas: as good as, or better than, we expected.

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Macmillan Dictionary

Macmillan Dictionary

Macmillan Dictionary is an award-winning, one-stop reference for English learners and speakers around the world.


  • There are no common mistakes in language usage. The very idea is an oxymoron.
    If it’s common, it’s not a mistake

  • Jimmy: I wouldn’t go that far. Putting an apostrophe in possessive its is very common, for example, but by current standards it is unequivocally a mistake.

    Norma: That sounds like a bogus rule, or a guideline that’s been overapplied. There are multiple situations where a comma can be used legitimately before and.

  • Jimmy, just because someone consistently makes the same grammar mistake, it doesn’t make it any less of an error.

    Norma, not using a comma before ‘and’ is a stylistic decision. Traditionally, a comma was always placed before ‘and’ in a list or between the conjunction of two phrases.

  • Well said, John. Jimmy, I’ve always been told that it’s counterproductive to keep making the same mistake in life. I guess then, if I continue, it will no longer be one? So, if you make a big mistake in your law firm, to avoid dismissal, do it regularly?

  • Hello Fabrice and thank you for your comment.

    If you read down through the post, you will see that the author deals with this question, just before the heading Faulty Parallelism:

    “Strictly speaking, apostrophes fall under orthography rather than grammar. In general usage, though, grammar often refers to spelling, punctuation, and style, so we’ve included the apostrophe here.”

    If you follow the link, you will find a post by Stan Carey on the broad and narrower senses of “grammar”.

  • Hello Karen. Thanks for your suggestion. The question of whether to use less or fewer is dealt with in this post by our Editor-in-Chief Michael Rundell. You can find the quiz he refers to here. There is also an associated video with Scott Thornbury.

  • I doubt that variation in use of the apostrophe will ever become ‘okay’. The apostrophe does not denote plurality, e.g. “Banana’s £1” – and inserting an apostrophe in this usage is no more right now than it was decades ago. “Bananas” is a plain, plural noun and it takes no apostrophe in the plural. The diversity in the way the decades are denoted, e.g. “The 1970’s were wonderful” is interesting. In my understanding, here, “1970” is a common noun, which becomes plural by adding an “s” in the usual way, to make it “1970s”. Anyone disagree?

  • Michael: In fact there is a lot of legitimate variation in apostrophe use, and there are items that can be pluralised with an apostrophe even in standard English. This short discussion on Twitter has examples, and links to a helpful article on the mark’s history.

  • What about the appalling examples below:
    the data IS. Sorry, folks, but the data ARE. One datum; two data
    the media IS. As above. One medium; two media
    “I was SAT” on a chair/I was STOOD in a queue. OK if somebody else made you sit down or made you stand. Otherwise please be sitting or standing.
    Alas, these horrors have now become so common in the media that I fear it may be too late….

  • Thanks for your comment, Margaret. Both data and media come from Latin roots, as you note, and in Latin they would take a plural verb. When they are used in English most people agree that both can legitimately be followed by a singular or plural verb. You can read our Editor-in-Chief’s thoughts on ‘data’ here.
    I think ‘was stood/sat’ is a slightly different case in that these are widely acknowledged to be informal or non-standard uses. They are common in some dialects of English (I have also heard ‘I was stood standing there’). I wouldn’t expect to see them in formal writing or indeed in formal reporting, but I’m not sure I ever have. Of course it is everyone’s right not to use them, as it is to always say or write ‘the data/media are’, but this is a personal choice.

  • This article was quite informative, particularly to the non-native speakers/writers! Thanks!
    I think you must take up another blog about the usage of gerunds and infinitives.

  • What is the proper and correct usage of “lest”? Sometimes it is used with may, and other times with should.

  • Thanks for your query Syed. ‘Lest’ is most often found these days either in old texts or in texts that want to appear old, such as historical novels. It is used in fixed expressions like ‘Lest we forget‘ and in quotations,like ‘Judge not lest ye be judged’ from the bible. As you point out and as our entry shows it can be followed by ‘should’, but this sounds rather formal and we would usually say ‘in case’ (in case she missed the phone). As you also point out, ‘lest’ can be followed by ‘may’ in sentences like: ‘Avoid applying the cream on the eyelids lest you may wake up in the morning with puffy lids’ or ‘Be sure to stick with your tour group lest you may lose your way in the maze of streets’. It can also be followed by a plain verb in the subjunctive: ‘Do not let the mixture boil lest it curdle’. All of these uses sound either formal or old-fashioned.

  • I am an EFL teacher and often notice language that I consider (or used to consider) incorrect. I know that language changes over time, but my question is what to teach and when to correct my students’ grammar. For instance, I would not teach “I like that ..” as in this sentence apparently quoted from a headteacher: “I like that I can pick and choose..”. (I would say: “I like being able to pick and choose” or “I like the fact that I can pick and choose”.) I am an older person and hate the fact that some of my contemporaries are boringly pedantic, but when does something become so acceptable that I should teach it? (I still can’t bring myself to teach: “How are you?” “I’m good”. Should I?)

  • Thanks for raising this interesting issue, Jean. It’s one that concerns a lot of teachers. We are hoping to publish a post on the subject soon, so watch this space.
    If any of our teacher readers have observations on the subject, please do add them using the comments box.

  • A query that’s not quite in line with the above on account of my chance discovery of the website, but did I once read that a sentence may have several semi-colons, as in punctuating a list, but on the other hand only one colon?

  • That’s not the case, luckily enough: more than one colon may be used in a sentence: like this. It’s probably best not overdone, but grammatically it’s fine. Here’s an example from Alan Garner’s novel The Owl Service: ‘We: want: the: key.’ Ali Smith’s book How to Be Both uses the technique frequently.

  • Which is correct: ‘The late James is the father of Jim’ or ‘The late James was the father of Jim’?

  • ‘I always understood a comma is never used before ‘and’ ?? Not in your sentence.’

    Americans like to use commas before ‘and’, the so-called Oxford comma, at all times. In the UK we don’t like it stylistically, so if it is actually necessary for clarity ( and it sometimes is) we prefer to rewrite the sentence to avoid the problem entirely.

    However, if you are a professional writer/sub-editor, you will consult the client’s style guide and do whatever it dictates, whatever your personal opinion.

  • Thanks for your comment, Nick. I don’t think it’s correct to say that “in the UK we don’t like the Oxford comma stylistically”, given that it is the house style of Oxford University Press. Some people like it and use it, others don’t, but I think it’s a matter of personal preference (and, as you say, preferred style) rather than a national preference.

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