Conjunctions: if, when

Introduction

We're going to have a barbecue if it's sunny.

If and when are conjunctions.

Joining two parts of a sentence

At the beginning of a sentence

I worked in Paris when I was young.

When I was young, I worked in Paris.

I'll give him your message if I see him.

If I see him, I'll give him your message.

Conjunction

Use

Examples

To talk about something that might or might not happen

We'll cancel the barbecue if it rains.

"Would you like to go out tonight?"

"Yes, if I'm not too busy."

when

To mean 'at a time'

To mean 'every time'

We were surprised when he told us about the new contract.

I always go by train when I visit my mother in the south.

I'll be late if I don't leave now.

Call me back when you have the information.

I usually take my husband to the airport when he travels on business. He calls me every day if he remembers!