First Conditional

¨We use the First Conditional to talk about future events that are likely to happen. We use the first conditional to talk about something that will happen (the result), if a particular condition (which is likely to happen) is met. Notice that the “if” clause (condition) is expressed in the present and the result or consequence clause is expressed

in the future using “will”.

Example: 

                                  If it rains, I will stay at home.

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? Notice that we are thinking about a future condition. It is not raining yet. But the sky is cloudy and you think that it could rain. We use the Present Simple tense to talk about the possible future condition. We use will + base verb to talk about the possible future result. The important thing about the first conditional is that there is a real possibility that the condition will happen.

¨If (condition) Present Simple, will + base verb (result) 

Examples:
If we invite John, he'll be really pleased.
condition result/likely consequence
If you give me some money, I'll pay you back tomorrow.

If they tell us they want it, we'll have to give it to them.
If Mary comes, she'll want to drive.

The 'if' clause can be used with different present forms:
If I go to New York again, I'll buy you a souvenir from the Empire State Building. (Present Simple)
If he's feeling better, he'll come. (Present Progressive)
If she hasn't heard the bad news yet, I'll tell her. (Present Perfect)

¨The “if” clause and the “will” clause can change positions but “will” cannot be in the same clause as the “if” clause. 

Example:
If they do not pass their exam, their teacher will be sad.
Their teacher will be sad if they do not pass their exam. 

If it rains tomorrow, will you stay at home?
Will you stay at home if it rains tomorrow?

If Mary wins the lottery, she will buy a new car.
Mary will buy a new car if she wins the lottery.

Wrong:
If Mary will win the lottery, she will buy a car. X