We use the first conditional when we are talking about real possibilities in the future.
For example: If I receive a bonus this year, I will travel to Europe.
We use the second conditional for hypothetical situations in the future.
For example: If I received more money, I would travel to Europe.
The difference between examples one and two is only the level of expectation of receiving more money. In example 1, receiving more money is a real possibility. In example 2, there is an acceptance that more money is improbable for the near future.
The third conditional is used for discussing hypothetical possibilities in the past. When we use the third conditional, the situation did not happen.
For example: If I had had more money last year, I would have traveled to Europe.
We often call this the “if only” conditional.
If only I hadn’t bought a new car I would have had enough money to go to Haiti.
If only I hadn’t had that last drink!
If only I had listened to your advice, I wouldn’t be in this trouble now.
Note: The third conditional has more than one possible result clause depending on whether the if clause would have affected an event in the past or would have affected the present situation.
For example: If I had studied law, I wouldn’t have joined an engineering firm.
If I had studied law, I would be a lawyer now.
This is used for general truths – facts that we consider to be true in all situations.
For example: When I have enough money, I go to Europe for my holidays.
When I have had enough money, I have gone to Europe for my holidays.
Other points about conditionals…
* We can reverse the ‘if clause’ and ‘result clause’ in the sentence.
e.g. I will travel if I receive a bonus.
* Sometimes the ‘if clause’ doesn’t include the word ‘if’!
e.g. Had you called, I would have gone. Should you call, I will go.
Using auxiliaries other than ‘would’ and ‘will’
With all the conditional sentences you can substitute the ‘auxiliary’ used to change the probability of the ‘result clause’.