If clause

We have four tipes of conditionals:
Zero Conditional
First Conditional
Second Conditional
Third Conditional

Zero Conditional
1) Form
In 'zero' conditional sentences, the tense in both parts of the sentence is the simple present:
NOTE: The order of the clauses is not fixed - the 'if' clause can be first or second:
Ice melts if you heat it.
You get wet if it rains.

2) Function
In these sentences, the time is now or always and the situation is real and possible. They are used to make statements about the real world, and often refer to general truths, such as scientific facts.

FIRST CONDITIONAL
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.
Form:

The second Conditional
Often called the "unreal" conditional because it is used for unreal - impossible or improbable - situations. This conditional provides an imaginary result for a given situation.
Note:The verb 'to be', when used in the 2nd conditional, is always conjugated as 'were'.

The Third Conditional
Often referred to as the "past" conditional because it concerns only past situations with hypothetical results. Used to express a hypothetical result to a past given situation.
Conditional 3 is formed by the use of the past perfect in the if clause followed by a comma would have past participle in the result clause. You can also put the result clause first without using a comma between the clauses.

Sometimes we use should have,could have,might have instead of would have
Example:If you had bought a lottery ticket,you might have won