شرح - Conditionals

  A Conditional Sentence

 shows that an action is reliant on something else (there's a condition).

The two most common conditionals are real and unreal, they are sometimes called if-clauses.

The real conditional (often named 1st Conditional or Conditional Type I) describes situations based on fact.

The unreal conditional (often named 2nd Conditional or Conditional Type II) describes unreal or imaginary situations.

There is also what we call the 3rd conditional (often named Conditional Type III), used to express no possibility of something having happened in the past, and the 0 conditional (often called the zero conditional) is used to express absolute certainty.

 1st Conditional Or Conditional 1
 The first conditional is used to express situations based on fact in the present or future (things which may happen). 

We never use will, or won't in the if part of the sentence.
For example:

• If I have time today, I will phone my friend. = I will phone my friend if I have time today. (It is possible that I will have time - therefore the condition is real).
• If I go to England, I will buy some Cheddar cheese. = I will buy some Cheddar cheese if I go to England. (It is possible that I will go to England - therefore the condition is real).