Use of conditionals
Zero conditional
When we talk about things that are generally or always true, we can use:
If/When/Unless plus a present form PLUS present simple or imperative
If he gets there before me, ask him to wait.
When you fly budget airline, you have to pay for your drinks and snacks.
Unless you need more space, a small car is big enough for one person.
Note that we are not talking about a specific event but something which is generally true.
In the condition clause, we can use a variety of present forms. In the result clause, there can only be the present simple or imperative.
If you visit London, go on the London Eye.
If unemployment is rising, people tend to stay in their present jobs.
If you’ve done that, go and have a coffee.
When you go on holiday, take plenty of sun cream. It’ll be very hot.
When I’m concentrating, please don’t make so much noise.
When I’ve finished an article, I always ask Kate to read it through.
Notice that ‘unless’ means the same as ‘if not’.
Unless he asks you politely, refuse to do any more work on the project.
Unless prices are rising, it’s not a good investment.
Unless you’ve been there yourself, you don’t really understand how fantastic it is.
The first conditional
We use the First Conditional to talk about future events that are likely to happen.
If we take John, he’ll be really pleased.
If you give me some money, I’ll pay you back tomorrow.
If they tell us they want it, we’ll have to give it to them.
If Mary comes, she’ll want to drive.
The ‘if’ clause can be used with different present forms.
If I go to New York again, I’ll buy you a souvenir from the Empire State Building.
If he’s feeling better, he’ll come.
If she hasn’t heard the bad news yet, I’ll tell her.
The “future clause” can contain ‘going to’ or the future perfect as well as ‘will’.
 (To be continued)
