The document discusses different types of conditionals in English. It explains that conditionals express what must happen before something else. It provides examples of zero, first, and second conditionals. Zero conditionals use the present simple in both clauses to talk about things that are always true. First conditionals use the present simple and will + infinitive to talk about real possibilities. Second conditionals use the past simple and would + infinitive to talk about impossible or unlikely situations.

1. A conditional is a sentence or part
of a sentence that expresses a
condition.
It usually begins with the words
"when," "if" and "unless ".
A condition is what must happen before
something else can happen.

2. We use the zero conditional to talk about things
that are always true.
*If you heat water, it boils.
*When the sun goes down, it gets dark.
*It lights up if you push that button.
(If + present simple, ... present simple)
The present simple is used in both clauses.

3. We use the first conditional when we talk about real and possible situations.
*I’ll go shopping on the way home if I have time.
*If it’s a nice day tomorrow, we’ll go to the beach.
*If it rains tomorrow, we'll go to the cinema.
If + Simple Present, + Will + Infinitive
OR
Will + If + Simple Present
In first conditional sentences, the structure is usually if + present simple and will +
infinitive. It’s not important which clause comes first.

4. The second conditional is used to talk about ‘unreal’ or impossible
things.
*If I won a lot of money, I’d buy a big house in the country.
*Where would you live if you could live anywhere in the world?
*If you didn’t smoke so much, you’d feel a lot better.
*If I had his number, I would call him. (I don't have his number now,
so it's impossible for me to call him).
If + Simple Past, + Would + Infinitive
or
Would + infinitive + If + Simple Past