По 3 примеры по second и third conditional

Second:
if all ou cars used vegetable oil,we wouldnt produce so much CO2.
If I were you I would study English by all means.
If people knew their future they would make fewer mistakes.
third:If it had not rained last night we would have visited our friends

If I had known his address I would have written him at once

If we had bought that house, we would have had to rebuild the kitchen