## When the water boils, add salt. When + the imperative

If and when can be confusing for non-native English speakers.

If = Something could happen.

When = it's for sure, something will happen.

Remember this example?

If you hear an alarm, leave the building immediately.

We know that an alarm could go off, and we now know what to do, just in case. We've been warned.

But look at this:

When you are finished with the test, raise your hand.

You know that you will finish. And you know what to do at that moment.

We can turn things around, too!

Call me when you get home.

I knowthat you will get home, and I want you to call me then.

Ready to give it a try?