Common mistakes learners make when forming conditional sentences

English has four conditional structures: the zero, first, second and third. In this post we look at some common problems that students of English have with the structure of conditional sentences.

First of all, here is a quick reminder of what conditional sentences are:

  • We use a conditional sentence to say that one event depends on another event, i.e. that something can only happen if something else happens first.
  • Conditionals sentences have two parts, which I will call the if-clause and the main clause.
  • The main clause depends on the if-clause.

Here are the most common mistakes when it comes to structure:

The zero conditional

In the zero conditional, both clauses are in the present tense. A common mistake is to use ‘will’ in the main clause:

If people eat too much, they will get fat.
If people eat too much, they get fat.
Water boils when it will reach 100°C.
Water boils when it reaches 100°C.


The first conditional

In the first conditional, we use the present simple in the if-clause and ‘will’ in the main clause. A very common error is to put ‘will’ in the if-clause:

If you will study more, your English will get better.
If you study more, your English will get better.
If I will see Peter, I’ll ask him.
If I see Peter, I’ll ask him.


The second conditional

This is used for hypothetical or improbable situations. We use the past simple in the if-clause and ‘would’ in the main clause.

Learners often make the mistake of putting ‘would’ in the if-clause*. In fact, this is one of the most common grammatical mistakes made by non-native speakers: I have heard Scandinavian and Dutch people who speak excellent English make this error repeatedly.

If you would study more, your English would get better.
If you studied more, your English would get better.
If I would have more time, I would take up golf.
If I had more time, I would take up golf.

* Note that native English speakers sometimes use ‘would’ in the if-clause when criticising people: If you would study more, your English would get better. This is not a grammar point most learners other than advanced-level learners need to focus on, however.


The third conditional

This is the most difficult conditional to master, probably as there are more auxiliary verbs to remember and the structure is therefore quite long. Again, ‘would’ should not be used in the if-clause:

If you would have studied more, your English would have improved.
If you had studied more, your English would have improved.

Another thing worth mentioning about the third conditional is the number of times native English speakers make mistakes with its construction. These examples show us how some people incorrectly insert ‘have’ into the if-clause:

If I’d have known earlier, I wouldn’t have done it. (‘d = had)
If I’d known earlier, I wouldn’t have done it. (‘d = had)

There are, of course, other errors which are common when learners use conditional sentences. I have only outlined the most frequent mistakes concerning structure.

If you are learning English, feel free to add a comment below and tell us if and how conditional sentences cause you problems.

You can see more examples of conditional sentences in our grammar section here. Learners can test themselves in our practice exercises here.

If you found this article useful, please click the ‘like’ and ‘+’ buttons below and share it with friends. Thanks.

Stuart is an English teacher and runs the Speakspeak website. He currently lives in Prague and has been teaching for over 20 years.


  1. fb - July 27, 2012, 1:16 pm Reply

    “If you would study more, your English would get better” may be wrong – but wouldn’t it be correct (or at least acceptable) in a question expressing politeness? “If you would help me out, I would be delighted?”

    • Stuart Cook - July 27, 2012, 1:27 pm Reply

      That’s correct. It’s a good example of when we CAN use ‘if’ and ‘would’ together in a conditional sentence – when we make a polite request.

      Another example is when we say ‘if only’ to express exasperation: ‘I only you would be more patient – it would help everyone.’

    • norida norbi - December 4, 2014, 5:37 am Reply

      thanks for the simple and useful guidance.

      • Stuart Cook - December 7, 2014, 10:16 pm Reply

        Thanks for stopping by and reading the article, Norida.

  2. terry sando - August 14, 2012, 11:25 pm Reply

    if i was/were a rich man ……
    is this a conditional tense?
    is was correct?

    • Stuart Cook - August 17, 2012, 8:01 pm Reply

      ‘If I was a rich man’ / ‘If I were a rich man’ are both second conditional. Some authorities and books insist that only ‘were’ is acceptable. However, both are widely used by native speakers today: ‘if I was’ is considered colloquial and less formal than ‘if I were’.

      • Mary Reed - February 12, 2013, 5:21 pm Reply

        If I were a rich man, I would…. Here we are using what is called the subjunctive mode. The subjunctive mode is used widely in other languages. Think about it’s use in The Lord’s Prayer: “Thy kingdom COME, Thy will BE DONE.” This is an example of using the subjunctive mode to make a request. If an eighty-year-old man begins a sentence with “if I were a young man” he is using the subjunctive mode correctly because he is not, in fact, a young man. This kind of use for the subjunctive is one of the few left in the the English language. Native speakers of Spanish will note that Spanish retains many more uses of the subjunctive than does English. I still insist on the “if I were” construction.

  3. FERNANDA CONTI CAJAL - August 30, 2012, 4:02 pm Reply





    • Stuart Cook - August 31, 2012, 8:04 am Reply

      Thanks for the question, Fernanda. ‘I wouldn’t have come’ is correct, while ‘I wouldn’t had come’ is always wrong.

      I don’t think I’ve ever heard a native speaker say ‘I wouldn’t HAD come’. It’s more usual for people to make a mistake in the ‘if’ clause by inserting an unnecessary ‘have': they say ‘if there’d have been a taxi’, when they should just say ‘if there’d been a taxi’ (without ‘have’).

  4. Summer - December 6, 2012, 9:54 pm Reply

    Excelente for mi!! It’s Very explained or so clear the usage of conditional mood!! Thanks a lot!!

  5. Roberto - May 8, 2013, 8:21 am Reply

    Thank you for excellent explanation! Thank a lot!

  6. vk.murugesan - June 30, 2013, 7:50 am Reply

    Thank a lot

  7. manoj india - August 6, 2013, 8:24 pm Reply

    Thanks a lot sir.

  8. marchwind - January 30, 2014, 7:56 am Reply

    My friend insists that “If I would have known, I would have told you. ” is a correct third conditional. I know that most Americans use this form but I tried to tell her it was incorrect. She studied English and Linguistics in college and refuses to cede to point, saying I am talking about British English and that it’s perfectly correct in American English. I know it’s colloquial, but it’s NOT correct.

    • Stephanie - July 19, 2014, 3:42 pm Reply

      A person’s perspective on the “correctness” of language might depend on what kind of linguistics she studied. If she is a descriptive linguist, she may be less concerned with what’s considered “correct” and more concerned with what people actually do with language. At some point, what people actually do will evolve into what’s considered correct, whether we like it or not. ;) I’m not always the biggest fan of this–I was horrified by the recent acceptance of “literally” for strong emphasis–but it’s the way language works and there’s just about no way to stop it.

  9. - June 9, 2014, 7:21 pm Reply

    Common mistakes learners make when forming conditional sentences

  10. Stephanie - July 19, 2014, 3:37 pm Reply

    “If I’d have known earlier, I wouldn’t have done it. (‘d = had)”

    Correct me if I’m wrong, but I think ‘d still equals WOULD here, not HAD. Nobody would say “If I had have known earlier, I wouldn’t have done it.” Or are you perhaps saying that people don’t recognize that ‘d can take the place of either WOULD or HAD, and that causes this error?

    Regardless, this is an excellent resource and really helpful for me as a teacher.

    • Stuart Cook - July 22, 2014, 11:41 pm Reply

      Hi, Stephanie
      I think you’re right when you say that people making that error are using would rather than had. I wrote ‘d = had in the example to indicate that the ‘d represents would once have is removed. It’s a little confusing, I admit.

      Either way, the problem seems to be that learners (and many native speakers, it must be said) incorrectly identify the ‘d contraction.

  11. Ghanshyam Patel - July 22, 2014, 3:39 am Reply

    Dear Sir,

    your lesson is excellent and more useful in speaking english.

    I would like to know the different between all conditional sentence.

    If you describe in more details, it would be easy to learn.

  12. Elena - August 13, 2014, 4:41 pm Reply

    I have a question about transforming first into third conditional for a specific sentence,this is for law school. The sentence goes like this: If he had been charged with a breach of the by-law, he could have claimed that it was invalid and the court would then have had to determine its validity before it could have decided wether he has/had commited an offence. Which one is correct,has or had and why? And is the rest of it alright?
    Thank you for your time.

    • Stuart Cook - August 15, 2014, 1:05 pm Reply

      Hello, Elena
      It should be . . . whether he had committed an offence. This is the past perfect tense, as we’re speaking in the past and the committing of the offence happened before the court decided. You could call it ‘the past before the past’, if you like.
      There’s a small error before that, too: before it could decide, not before it could have decided.

      Hope that helps.

  13. Louise - September 23, 2014, 4:30 pm Reply

    Good day!Can I use your examples for my research paper.Thank you:)

  14. Kinga - December 2, 2014, 4:59 pm Reply

    Is there any chance this sentence is correct- as polite version?

    If you would be interested in the offer please send me your documents.

    • Stuart Cook - December 7, 2014, 10:38 pm Reply

      It should be If you ARE interested, please send me . . . .
      As a polite alternative, you could say Should you be interested in . . . , please . . . .

  15. emmanuel godwin - December 11, 2014, 11:31 pm Reply

    i really love your lesson wit passion sir,thanks a lot

  16. Marcin Osinski - March 10, 2015, 1:38 pm Reply

    Hi Stuart,
    I had a talk with a group of soldiers, and they asked some specific questions about conditionals. Expressions starting with ‘If I were a soldier’ and ‘If I had to face the enemy on the battlefield’ seem to be easy, but how about hypothesizing about past historical events? ‘If I fought in the WWII’ or ‘If I had fought in the WWII’? ‘If I had been fighting in the Prague uprising’ or ‘If I fought in the Prague uprising’?
    Any suggestions welcome

    • Stuart Cook - March 13, 2015, 12:10 pm Reply

      Hi, Marcin
      To express past hypothesis, we use the third conditional. We’d say:
      ‘If I had fought in WWII’ and ‘If I had fought in the uprising’. (Note the past perfect structure in there – ‘I had fought’, as opposed to ‘I fought’, which we use in the second conditional.)

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