There are several structures in English that are called conditionals or if conditionals.
"Condition" means "situation or circumstance". If a particular condition is true, then a particular result happens:
- if y = 3 then 2y = 6
There are three basic English conditionals as well as the so-called zero conditional. There are some more conditionals that we do not use so often.
Structure of Conditional Sentences
The structure of most conditionals is very simple. There are two basic possibilities.
Of course, we add many words and can use various tenses, but the basic structure is usually like this:
|if||y = 10||2y = 20|
or like this:
|2y = 20||if||y = 10|
This structure can produce, for example, the following sentences:
- If I see her, I will tell her.
- I will tell her if I see her.
Notice the comma in the first sentence. (A comma is always correct in this case, but not always essential if the sentence is short.) In the second sentence we do not normally use a comma.
for real possibility
We are talking about the future. We are thinking about a particular condition or situation in the future, and the result of this condition. There is a real possibility that this condition will happen. For example, it is morning. You are at home. You plan to play tennis this afternoon. But there are some clouds in the sky. Imagine that it rains. What will you do?
|Present Simple||will + base verb|
|If||it rains,||I will stay at home.|
Read more about the First Conditional
for unreal possibility
The second conditional is like the first conditional. We are still thinking about the future. We are thinking about a particular condition in the future, and the result of this condition. But there is not a real possibility that this condition will happen. For example, you do not have a lottery ticket. Is it possible to win? No! No lottery ticket, no win! But maybe you will buy a lottery ticket in the future. So you can think about winning in the future, like a dream. It's not very real, but it's still possible.
|Past Simple||would + base verb|
|If||I won the lottery,||I would buy a car.|
Read more about the Second Conditional
for no possibility
The first conditional and second conditionals talk about the future. With the third conditional we talk about the past. We talk about a condition in the past that did not happen. That is why there is no possibility for this condition. The third conditional is also like a dream, but with no possibility of the dream coming true.
Last week you bought a lottery ticket. But you did not win. :-(
|Past Perfect||would have + past participle|
|If||I had won the lottery,||I would have bought a car.|
Read more about the Third Conditional
We use the so-called zero conditional when the result of the condition is always true, like a scientific fact.
Take some ice. Put it in a saucepan. Heat the saucepan. What happens? The ice melts (it becomes water). You would be surprised if it did not.
|Present Simple||Present Simple|
|If||you heat ice,||it melts.|
Read more about the Zero Conditional
Summary of Conditionals
Here is a table to help you to visualize the basic conditionals.
Do not take the 50% and 10% too literally. They are just to help you.
|100%||zero||If you heat ice, it melts.||any|
|50%||1st||If I win the lottery, I will buy a car.||future|
|10%||2nd||If I won the lottery, I would buy a car.||future|
|0%||3rd||If I had won the lottery, I would have bought a car.||past|