We use the zero conditional to describe something that is generally true (a fact).

     Example: If people study, they usually pass their exams.

     A conditional like this has two clauses: a dependent clause beginning with if and the main clause (or result clause).

    We use the zero conditional to show the direct result or consequence of a particular action, given a specific condition.

    Example: When people are sad (condition), they cry. (result or consequence of being sad).

   The form of the zero conditional is:

    When / if + S + V (simple present) + O, S + V (simple present) + O

Examples: 

    – When I wake up early, I feel sleepy.

    – If my mom makes coffee, I drink a lot of it.

    As we can see, the two clauses of the conditional sentence are in the simple present form.

Practice this lesson here: ZCOND001.