Zero conditional: If + subject + Present Simple, subject + Present Simple
—> talks about a general truth/fact
eg. If water reachs 100 degrees, it boils.
NB: we can use ‘when’ instead of ‘if’ in zero conditionals
First conditional: If + subject + Present Simple, subject + will + infinitive
—> talks about a future possibility
eg. If you study hard for the exam, you’ll pass.
NB: we can use ‘might’ instead of ‘will’ to mean ‘will perhaps’ in first conditionals
Second conditional: If + subject + Past Simple, subject + would + infinitive
—> talks about unlikely or hypothetical situations in the present or future
eg. If I won the lottery, I’d travel around the world.
NB: we can use ‘could’ instead of ‘would’ to talk about ability or possibility, and
we can use ‘might’ instead of ‘would’ to mean ‘would perhaps’ in second conditionals
Third conditional: If + subject + Past Perfect, subject + would + have + past participle
—> talks about hypothetical situations in the past
eg. If I hadn’t gone to London, I wouldn’t have met my boyfriend.
NB: we can use ‘could’ and ‘might’ instead of ‘would’ to mean ‘would perhaps’ in third conditionals
It is possible to use a variety of verb forms in conditional sentences, not just those in the four basic conditionals.
– We can use the future with going to instead of the present to show future intention.
eg. If you’re going to buy a house, you’ll need to get a mortgage. (variation of first conditional)
– We can use a continuous form instead of a simple form to emphasise an action in progress.
eg. He wouldn’t have seen her if he hadn’t been jogging through the park. (variation of third conditional)
– We can use a modal instead of a present form to give advice, for example.
eg. If the medicine has no effect, you should return to the doctor. (variation of a zero conditional)
In mixed conditionals, the main clause and the ‘if’ clause sometimes refer to a different period of time.
The most common combinations are second and third conditionals.
eg. If I hadn’t had a tattoo, I wouldn’t be disappointed now. ( If clause refers to the past, main clause refers to the present)
If I had remembered to lock the door, we would still have our TV. (If clause refers to the past, main clause refers to the present)
If they weren’t so skilled at their jobs, they would have been fired long ago. (If clause refers to the present, main clause refers to the past)
If I hadn’t lost my passport, I’d be leaving tonight. (If clause refers to the past, main clause refers to the future)
We can use ‘should’ or ‘happen to’ in the ‘if’ clause in the first conditional if we want to suggest that something is very unlikely. We can also combine the two.
eg. If anyone happens to see the wanted man, they should call the police immediately.
Should anyone come across the stolen goods, they should phone this crime hotline.
If anyone should happen to get a photo of the man, they should hand it in to the police immediately.
We can use inversion in unreal conditional sentences when the first verb of the ‘if’ clause is were, had or should. We can leave out if and put the verb at the beginning of the clause.
eg. Were they to discover the treasure, they would be millionaires. (If they were to discover the treasure…)
Had he gone to India instead of China, he would never have become fluent in Chinese. ( If he had gone to India…)
Should you have any more trouble, please don’t hesitate to call. ( If you should have any more trouble…)