Conditionals: third and mixed
Look at these examples to see how third and mixed conditionals are used.
We would have walked to the top of the mountain if the weather hadn't been so bad.
If we'd moved to Scotland when I was a child, I would have a Scottish accent now.
If she was really my friend, she wouldn't have lied to me.
Try this exercise to test your grammar.
- Grammar test 1
Read the explanation to learn more.
Grammar explanation
Do you know how to use third and mixed conditionals?
Third conditionals and mixed conditionals
Conditionals describe the result of a certain condition. The if clause tells you the condition (If I hadn't been ill) and the main clause tells you the result (I would have gone to the party). The order of the clauses does not change the meaning.
If I hadn't been ill, I would have gone to the party.
I would have gone to the party if I hadn't been ill.
Conditional sentences are often divided into different types.
Third conditional
The third conditional is used to imagine a different past. We imagine a change in a past situation and the different result of that change.
If I had understood the instructions properly, I would have passed the exam.
We wouldn't have got lost if my phone hadn't run out of battery.
In third conditional sentences, the structure is usually: If + past perfect >> would have + past participle.
Mixed conditionals
We can use mixed conditionals when we imagine a past change with a result in the present or a present change with a result in the past.
1. Past/Present
Here's a sentence imagining how a change in a past situation would have a result in the present.
If I hadn't got the job in Tokyo, I wouldn't be with my current partner.
So the structure is: If + past perfect >> would + infinitive.
2. Present/Past
Here's a sentence imagining how a different situation in the present would mean that the past was different as well.
It's really important. If it wasn't, I wouldn't have called you on your holiday.
And the structure is: If + past simple >> would have + past participle.
Do this exercise to test your grammar again.
- Grammar test 2
Hello Ahmed Imam,
The sentence is not correct. We use unless to describe things that we are not sure of, not to describe things that we know are true or not true. Since we know that Shakespeare moved to London, we would use if...not and not unless.
Peter
The LearnEnglish Team
Hello Ahmed Imam,
The sentence is unusual, but correct. We can use a negative form after unless when it describes something that we do not expect. In other words, in your example the speaker believes Mary is studying or will study.
Here are a few more examples:
Note that a positive verb is needed in the first clause. We do not use a negative verb with unless and another negative verb.
Peter
The LearnEnglish Team
Hello CareBears07
As Swan mentions in the following sentence, 'if' can be used in many situations, not just those that teachers often call zero, first, second, third and mixed conditionals. (I'm not sure what edition you have, but if it's the third edition, read on to section 257. I'm not sure where he explains this in other editions.)
Particularly when the 'if' clause does not refer to an imaginary situation -- which seems to be the case in the sentence you cite -- all kinds of verb tenses can be used. In other words, this sentence could mean that we know that she did not phone this morning, and since she did not phone this morning, one possible explanation for this is that she's away.
Hope this helps.
All the best
Kirk
The LearnEnglish Team
Hello Anna
I'm not familiar with that rule. The rule doesn't sound correct to me and in fact your example sentence is correct!
All the best
Kirk
The LearnEnglish Team