Zero Conditional

The Zero Conditional is used to talk about something that is always true, or facts

If you heat water, it boils.

If I go to visit my mother, I take some flowers.

The structure is:

If clause, Result clause
If present simple, present simple.
If you heat water, it boils.

The structure can be reversed. In this case, do not use a comma.

Result clause If clause
present simple If present simple
Water boils. if you heat it.

When

We can substitute ‘if’ with ‘when’. We use ‘if’ to suggest something is possible. We use ‘when’ because something is certain to happen.

If I go to visit my mother, I take some flowers.

When I go to visit my mother, I take some flowers.

Click on these links to learn more about the Conditionals

Introduction

First Conditional

Second Conditional

Third Conditional

Mixed Conditionals

Conditionals – Alternatives to If