FIRST CONDITIONAL

We use the first conditional when we talk about future situations we believe are real or possible.

Examples:

    If it doesn't rain tomorrow, we'll go to the beach.

    When I finish work, I'll call you.

STRUCTURE

IF/WHEN + Present Simple sentence, future simple sentence.

It is also common to use this structure with unless, as long as, as soon as or in case instead of if.

     I'll leave as soon as the babysitter arrives.

     I don't want to stay in London unless I get a well-paid job.

     I'll give you a key in case I'm not at home.

    You can go to the party, as long as you're back by midnight