Zero Conditional

IF | Condition | Result |
present simple | present simple | |
If | you boil water | vapor rises. |
This is different than the other conditionals since the outcome is not questionable. The vapor rises; end of story. We are not concerned about past or future, we are referring to facts and conditions that always hold true.
IF | Condition | Result |
present simple | present simple | |
If | I run too fast | my knees hurt. |
If | you whisper | I can’t hear. |
If | you stay quiet | I can hear the water. |
If | the door closes | I won’t get on the plane. |
You can change the order of the clauses as seen below:
Result | IF | Condition |
present simple | if | present simple |
My knees hurt | if | I run too fast. |
I can’t hear | if | you whisper. |
I can hear the water | if | you stay quiet. |
I won’t get on the plane | if | the door closes. |