If + Past Simple, ...Would + Verb
We use a past verb though are imagining the present or the future to be different.
The second clause of subject + would + verb (conditional verb) is conditional to the first clause happening (or will only happen if the first part/clause happens).
Example: If I won the lottery, I would travel around the world.
- If I didn't have a headache, I would go to the party.
- If I became President, I would reduce the salaries of all politicians. (Though it is unlikely I will become President)
Notice how we use a comma after the past tense clause.
We can also reverse the order and use: