Conditional

Third conditional structure

If + past perfect + would + have + past participle

Zero conditional structure

If + present simple + present simple or infinitive

Second conditional structure

If+past simple+ would+ infinitive

First conditional structure

If+present simple+will+infinitive

Third conditional use

It's used to describe a situation in the past that didn't happen, and to imagine the results of this situation.

First conditional use

It's used to talk about things which might happen in the future. It describes possible things which likely come true.

Zero conditional use

It's used when the result will always happen.

Second conditional use

(Imaginary future) if the situation is possible, but not necessarily probable, if it is more hypothetical we use the second conditional