Zero Conditional

The zero conditional is for stating what the speaker regards as fact, it describes what happens in general.
FORM
1 If + condition + result:
If + present simple (condition clause)     ,     present simple (result clause)
If you freeze water     ,                                     it becomes ice.
If you mix water and oil     ,                            they separate. 
2 Result + if + condition:
Present simple (result clause)     if + present simple (condition clause)
They always bring a present              if they come home.
People die                                          if they don't eat.
We can also use when/whenever instead of if
When you heat water, it boils.
Water boils when you heat it.

EXERCISES

Zero Conditional 1

Zero Conditional 2