Zero Conditional is used to express a general truththe probable future.

In the if/when-clause we usually use Present SimpleFuture Simple.

In the main clause we usually use Present SimpleFuture Simple.

In this type of conditionals, we cancannot use "when" instead of "if".

"Unless" means "if""if not".

When the main clause comes before the if-clause, we usedo not use a comma between them.

When the if-clause comes before the main clause, we usedo not use a comma between them.