Rule: Second and Third Conditional ShowHide

Second conditional

If + Past Simple, would + verb

An imagined situation in the present or future – not true, or not likely.

If she had your phone number, she would call you.
If I won the lottery, I would visit Canada.

For advice: If I were you, I would see a doctor. In this phrase it is were, even with I.

Third conditional

If + had + 3rd form, would have + 3rd form

An imagined past: it didn't happen, so we picture a different result – often a regret.

If Anna had got up earlier, she would have caught the bus.
If they hadn't won that match, the club would have fired the manager.

would never goes in the if-part: If I knew …, not If I would know. could or might can take its place: If I had more time, I could learn the guitar.