Read the grammar explanation and do the exercise.

Third conditionals and mixed conditionals

Conditionals are sentences with two clauses – an if clause and a main clause – that are closely related. Conditional sentences are often divided into different types.

Third conditional

Third conditional sentences describe the past. They describe something that didn't happen.

  • If I'd studied harder at school, I would have gone to university.

He didn't study very hard and he didn't go to university.

  • We wouldn't have got lost if you hadn't given me the wrong directions.

She wasn't given the correct directions and she didn't find her way.

  • She might have finished the exam if she'd had more time.

She didn't finish the exam and she didn't have more time.

In third conditional sentences, the structure is usually if + past perfect and would + perfect infinitive (e.g. have done). It's not important which clause comes first.

Notice that other modal verbs can be used instead of would (e.g. could, might, may)

Mixed conditionals

In mixed conditional sentences the time in the if clause is not the same as the time in the main clause. There can be various combinations.

  • If he'd gone to university, he might have a better job.

He didn't go to university (past)
He doesn't have a very good job. (present)
This sentence shows the present consequences of a past action.

  • If I'd won the competition, I'd be going to Florida next week.

She didn't win the competition (past)
She isn't going to Florida (future)
This sentence shows the future consequences of a past action.



Language level

Upper intermediate: B2


Hi Tommaso,

No, we wouldn't use that construction.  We can form negatives in the past simple with 'hadn't got' or with 'didn't have', but not just *'hadn't'*.

Best wishes,



The LearnEnglish Team

hi peter please let me now what is the different A- I will come and I shall come
also they shall come and they will come

Hi kush1,

shall is mostly used to offer to do something or to ask for instructions - this is explained in the section called Offers and invitations on our ability, permissions, requests and advice page.

It can also used as an alternative to will for the subjects I and we in some instances, and is also used in other ways, but these uses are not nearly as common. 'I shall come' does indeed mean the same as 'I will come', but 'they shall come' is not really used in modern spoken English.

I hope this helps you.

Best wishes,
The LearnEnglish Team

Hi, I'm new here and look forward to learn from you guys.

Yesterday I posted my query but it didn't appear, so I'm posting it again now. Thank you for being patient.
I'm doing a correct mistake exercise on Relative clauses and Reduced relative clauses (-ing clauses and -ed clauses). Please tell me if we can always change a relative clause into a reduced relative clause. If not, why not?
In the sentence below, I have to correct a mistake. Can I rewrite it in both types of clauses? According to the key of the exercise, it's rewritten in relative clause.
"Like other women PIONEERED => WHO PIONEERED or PIONEERING (or both) in the field medicine, Sara Mayo found the beginning years difficult."
Thanks for your help.

P/S: sorry if my query is not clear enough. I'll try to explain again if needed.

Hello Fallvn,

Questions are always moderated here on LearnEnglish to remove spam and suchlike, so there is always a delay between posting and the post appearing; please be patient with this and the question will appear.

Our role here on LearnEnglish is to help our users to understand the information on the site, not to help with other exercises from other sites, tests or class- or homework. If we tried to do this then we would have no time for anything else, quite apart from the fact that we have no idea of where these exercises come from and of what quality they are. We certainly do not wish to get involved in explaining rules or examples which may be badly phrased, inaccurate or incomplete, for obvious reasons. For example, the sentence you posted contains a grammar error quite apart from the question of the relative clause (we would say 'the field of medicine'). In short, if you need help with exercises from elsewhere then you need to ask the authors of those exercises for help or explanation.

That said, I will tell you that 'pioneered' is wrong here, but both 'who pioneered' and 'pioneering' are grammatically possible.

You can find more information on participle clauses here, and more information on relative clauses here and here.

One last point regarding questions and posts: we'd appreciate it if you could try to post questions on relevant pages (so a question about reduced relative clauses would be posted on the page related to relative clauses rather than this one, which is about conditionals). This is so that other users who are studying a given topic can find the question and learn from it and its answer; if questions appear on random pages then they become much harder to find and much less useful to other users.

Best wishes,



The LearnEnglish Team

Hello Peter,
Sorry for any convenience I caused and thank you for your explanation. I really appreciate it.
I was new here so I really didn't know where to post my query although I tried to look for an appropriate page and I wrongly thought it was OK to post my question here. Sorry about that. I'll be more careful next time.
As for the exercise I did, it's from an exercise book, so it's impossible for me to ask the authors for help. (The interaction between exercise book authors and learners is not popular in my country.) I've studied English by myself, so when I found your site I felt very lucky to have a chance to consult professionals. Thanks for that.
By the way, in 'the field medicine', I omitted "of" when typing the sentence. Sorry about it. I'll pay more attention to my typing next time.
Again, I'd like to thank you for understanding. Thanks for your help and your patience. Hope to get more help from you in the future.
Best wishes,

Hi, i am new here. Thanks for providing such a great learning platform.
Sir I have a little confusion and wish you to resolve it..
Above, in last sentence you have used past simple in if clause.
Could we use present simple instead of using past simple.

Thank you in advance

Hi Syed sami ul haq,

It is possible to use the present simple in the if-clause, but the meaning is then changed. We use [if + present... (then) will + verb] for likely or real events, and [if + past... (then) would + verb] for unlikely or unreal events.

You can find more information on these types of conditional sentences, sometimes called first and second conditional forms, on this page.

I hope that helps to clarify it for you.

Best wishes,



The LearnEnglish Team

Sir, could you please explain me if I use present simple in the sentence what meaning it will give and if pasr simple is used what will be the difference in meaning. If possible explain it using example. Because it is quite difficult for me to recognize what situation it is, I mean likely or unlikely.