Zero, first, second, third and mixed conditionals
You can see a full explanation of type 0, type 1, type 2 and type 3 conditional with examples.
We use mixed conditionals if we want to mix talking about the present and the past in the same sentence. The mixed conditional is a combination of the second and the third conditional:
1We can use past simple or continuous in the if-clause (to refer to the present or future), and would/should/might have + past participle in the main clause (to refer to the past).
2We can also use past perfect in the if-clause (to refer to the past), and would/should/might + infinitive (to refer to the present).
- If I didn’t have (second conditional) so much work, I would have gone (third conditional) to the party last night.
- If I spoke (second conditional) German, I would have understood (third conditional) them.
- If I had won (third conditional) the lottery, I would be (second conditional) rich.
- If I hadn’t dropped (third conditional) school, I could have (second conditional) a better job now.
Alternatives to if in conditional sentences
as long as / provided (that) / providing (that) / on condition (that) / only if
We can use the expressions as long as, provided/providing (that), on condition (that), or only if instead of if when we want to emphasize the condition that needs to be present so that something can happen or be done.
- I’ll tell you what really happened as long as you keep the secret.
- I’ll lend you the money provided (that) you pay me back next month.
- They will speak to the press on condition (that) they remain anonymous sources.
- We will invest the money, but only if you can prove that it’s a safe investment.
whether or not
We use whether or not when there are two alternatives and we want to say that something will happen or will be true in any of those two alternatives. Compare:
- I’ll help him if he needs me. (=I will help him only if he needs me.)
- I’ll help him whether or not he needs me. (I will help him if he needs me, and I will help him if he doesn’t need me, too.)
We also use even if to mean ‘whether or not’ (for emphasis).
- Even if you apologise, he’ll never forgive you. (=Whether or not you apologise, he’ll never forgive you.)
suppose / supposing
We normally use suppose or supposing at the beginning of a sentence to make someone imagine a situation. It means ‘what would happen if’, or simply ‘if’ (imagining a situation).
- Supposing I got a job, I wouldn’t be able to travel with you next summer.
- Suppose she doesn’t believe you, what would you do then?
Inversion in conditional sentences
should you find
In first conditional sentences it’s possible to use should at the beginning of the sentence instead of if. This form is formal and it’s quite common with an imperative form in the main clause.
- Should you find the answer, please let me know as soon as possible. (=If you find the answer)
- Should you change your mind, you know where to contact us. (=If you change your mind)
had we arrived
In third conditional sentences, we can invert the auxiliary verb had and leave if out. Had we arrived = If we had arrived.
- Had we arrived earlier, we could have prevented the incident.
- Had they looked further into the data, they might have realised there was a mistake.
were we to announce
We can also find cases of inversion with this structure: were + subject + to. + infinitive. It is used to talk about future improbable events (like the second conditional).
- Were we to announce the truth, we would receive a lot of criticism. (=If we announced …)
- Were they to buy a new house, they would need to sell the old one first. (=If they bought …)
Negative forms: should I not, had we not, were we not
When should, had or were are negative, contracted forms are not possible, and not is used after the subject.
- Should you not wish to retake the test, you must let us know before the end of June. (NOT
Shouldn’t you wish)
- Had you not refused my invitation, we would have had the most incredible time in our lives. (NOT
Hadn’t you refused)
- Were you not my brother, I would call the police. (NOT