Do you know how to use third and mixed conditionals?

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


Hello gerol2000
The first sentence here is similar to sentence you were asking about in another comment. It mixes a present or future condition ('if I could') with an imaginary past consequence ('I would have done it'), and this combination doesn't make sense. Perhaps in some very specific context it would be possible, but I can't think of one off the top of my head.
The second sentence is perfect!
All the best
The LearnEnglish Team

Thanks again for resolving my doubts. With all this in mind, would it be always correct to say
'If I could do it, I would do it' for present or future
'I would have done it if I could have done' for past
'If I had done that, I wouldn't have done this.' for past

'If I had done that, I wouldn't be doing this' - mixed with present result?

Hello gerol2000
Yes, that looks correct to me. Congratulations!
All the best
The LearnEnglish Team

And still, Dear Kirk, do you think this, that I have found doing some on-line test,
'If anyone of them could sew, she would have done a tablecloth for them all'
should be rearranged as
'If anyone of them had been able to sew, she would have done a tablecloth for them all'?
Am I right thinking that the first is just American English, where implied result can be used with present condition?
So, 'If I had been in your shoes, I wouldn't have done it' is better than 'If I were you, I wouldn't have done it', isn't it?

Hi gerol2000
One of the reasons we don't normally comment on sentences from other sources is that often the sentences are not completely correct or natural, at least in standard British or American varieties of English. The first sentence you ask about is one such sentence, which sounds odd or wrong to me in several places.
As for your last question, yes, I agree, the sentence you suggest is better than the other one. I'm sure you could hear or read that sentence (with the mixed conditional), though, so please don't see surprised if you see something similar in a text or hear someone say something similar.
All the best
The LearnEnglish Team

Thank you, Kirk. I also felt something was wrong with that first sentence. And, at least, now I won't use that source to practise subjunctive anymore. To tell the truth, I often come across similar doutful mixed sentences when surfing the web in search of a trustful resource for efficient subjunctive practising.
All the best,

Hello, please consider this, would it be correct to say
'If I didn't go there, I wouldn't have known what to do yesterday'.

Hello gerol2000
I'm afraid that is not correct. Because the sentence speaks of the present or future affecting the past -- the condition ('I didn't go there') refers to a present or future imaginary action, and the result ('I wouldn't have known what to do yesterday') refers to an imaginary action in the past -- the sentence is confusing.
If you changed the condition clause to 'If I hadn't gone there', then it would be a grammatically correct third conditional sentence.
All the best
The LearnEnglish Team

One more question, please. Would it be correct if I said 'If didn't go there yesterday, I wouldn't have known what to do'

Hello gerol2000
Although people would understand you, and you might even find some native speakers say that, I wouldn't recommend using this sentence. This is because, in conditional sentences, 'hadn't gone there' refers to the past, and 'didn't go there' refers to the present or future. It sounds strange to combine 'yesterday' with a form that talks about the present or future.
All the best
The LearnEnglish Team