Conditionals: the second conditional

The form

If + Past Simple, + Would + Infinitive

Would + Infinitive + If + Past Simple (notice that there is no comma in this version)

Usage

FUTURE

1. To talk about improbable or impossible events in the future.

If I met Donald Trump, I would be shocked.

If I won the lottery, I would buy a sports car.

He would travel all over the world, if he were rich.

We always use were instead of was in the second conditional. Why? It is an exception to the rule. If the verb in the if clause is “to be,” use “were,” even if the subject of the clause is a third person singular subject (i.e., he, she, it).

If I were you, I would call the police.

If she were clever, she would pass the exam.

PRESENT

2. To talk about something that is impossible, since it isn't true at the moment of speaking.

If I had his numer, I would call him. (but I don’t have his numer)

If I were you, I would take an umbrella. (but I’m not you)

If they stopped talking, they would learn something. (but They were constantly talking)

He would be in trouble, if he missed the train. (but He caught the train)