Form
If + S + Past Simple, S + would/wouldn’t + Verb.
If I won the lottery, I would travel the world.
He would feel healthier if he exercised more.
Meanings
Imaginary or Unlikely Situations
We use the Second Conditional to talk about situations in the present or future that are not real, or are very unlikely. The past tense in the ‘if’ clause does not refer to past time; it signals that the situation is imaginary.
Compare with First Conditional:
First: If I have time, I will help you. (A real possibility).
Second: If I had time, I would help you. (Imaginary – I don’t have time).