The conditional tense is used in English to describe a hypothetical situation- something that is possible or impossible. The conditional tense can be divided into four different structures:
The Zero Conditional
The zero conditional is used to describe something that is true, when a condition is completed or met. This conditional tense is generally used for universally known facts:
If you run, you sweat.
If I drink a lot of alcohol, I get a hangover.
If it’s icy, the floor is slippery.
In all of the above examples, the second event is only true if the first event happens.
The First Conditional
The first conditional tense describes a very possible future situation. It always involves at least two futre events and the second event can only be true if the first event is completed.
If it is sunny, I will go to the beach.
If she does well in the interview, she will get the job.
If Lewis asks Jooles to marry her, she will say “yes”.
In all of these examples, the second event is only true where the first event or condition is completed.
The Second Conditional
The second conditional is used to describe unlikely situations in the present or near future. Although the situations can often be possible, the emphasis is that it is unlikely or improbable that the condition will be met in order to make the situation a reality. The second conditional is often used to describe desires, dreams and wishes.
If I won the lottery, I would buy a huge mansion.
If Heather lived in New Zealand, she would live in Aukland.
If Onur was a vegetarian, she wouldn’t eat meat.
All of the above examples are technically possible situations (it’s possible to win the lottery, if you play) but they are all very unlikely situations. To express this, we use the second conditional tense.
The Third Conditional
The third conditional tense is used to describe a completely hypothetical situation in the past. As we are unable to change the past, the third conditional can only ever be an impossible, imaginary situation. This gramatical tense is often used when we regret something, when we imagine how things may have been different in different circumstances etc.
If I had been born in France, I would have spoken French.
If Helen had seen the painting first, she might have bought it.
If Craig hadn’t been born in Oxford, he would have had a very different accent.